SSM+Maven高级+MybatisPlus万字笔记

谁践踏了优雅 2023-09-29 15:23 14阅读 0赞

### SSM框架学习 ###

前言：花了一周学习了SSM(Spring+SpringMVC+Mybatis)以及Maven高级部分加MybatisPlus并且做了这个笔记，自己看黑马视频做的总结，不得不说学习还得多做笔记，做完笔记后还得在回头回忆一遍，遇到没记住的部分可以回来翻阅，很方便。仅上传作纪念，之前看JavaWeb也有记笔记，到时候有时间再放上来，仅供参考，有做的不好的地方还请多多指教！

##### 一：Spring Framework系统框架 #####

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##### 二：Spring核心概念 #####

###### 1.IoC、Bean、DI ######

###### **1.1：IoC&Bean** ######

*  IoC(Inversion of Control)控制反转
    
     *  使用对象时，由主动new产生对象转换为由**外部**提供对象，此过程中对象创建控制权转移到外部，此思想称为控制反转。
     *  Spring提供了一个容器，称为IoC容器，用来充当IoC思想中的"外部"
     *  IoC容器负责对象的创建、初始化等一系列工作，**被创建的对象**在IoC容器中被称为**Bean**。

###### **1.2：DI** ######

*  DI(Dependency Injection)依赖注入
    
     *  在容器中建立Bean与Bean之间的依赖关系的整个过程，称为依赖注入。

###### **1.3：最终效果** ######

*  充分解耦
 *  使用IoC容器管理Bean
 *  在IoC容器内将有依赖关系的Bean进行关系绑定(ID)
 *  使用对象时不仅可以直接从IoC容器中获取，并且获取到的Bean已经绑定了所有的依赖关系。

###### 2.快速入门 ######

###### 2.1：导入相关坐标 ######

``

<dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.2.21.RELEASE</version>
    </dependency>

###### 2.2：定义Spring管理的类(接口) ######

public interface BookDao {
        
        public void save();
    }
    
    public class BookDaoImpl implements BookDao {
        
        public void save() {
        
            System.out.println("book dao save ...");
        }
    }
    
    public interface BookService {
        
        public void save();
    }
    
    public class BookServiceImpl implements BookService {
        
        //5.删除业务层中使用new的方式创建的dao对象
        private BookDao bookDao;
    
        public void save() {
        
            System.out.println("book service save ...");
            bookDao.save();
        }
        //6.提供对应的set方法(容器在执行)
        public void setBookDao(BookDao bookDao) {
        
            this.bookDao = bookDao;
        }
    }

###### 2.3：创建Spring配置文件，配置对应类作为Spring管理的Bean ######

`applicationContext.xml`

<bean id="bookDao" name="dao bookDaoImpl" class="com.my.dao.impl.BookDaoImpl"/>
        <bean id="bookService" class="com.my.service.impl.BookServiceImpl">
            
            
            <property name="bookDao" ref="bookDao"/>
        </bean>

###### 2.4：初始化IoC容器(Spring核心容器/Spring容器)，通过容器获取Bean ######

public static void main(String[] args) {
        
        //3.加载配置文件得到上下文对象，也就是容器对象
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
    
        //4.获取资源
        // BookDao bookDao = (BookDao) ctx.getBean("bookDao");
        // bookDao.save();
        
        BookService bookService = (BookService) ctx.getBean("bookService");
        bookService.save();
    }

###### 3：bean的作用范围 ######

*  scope属性用于改变bean的作用范围，默认情况下scope属性为singleton，此时为单例模式，即创建出来的bean都是同一个，当scope属性为prototype时候，即为非单例模式。
 *  为什么bean默认情况下为单例模式？可以用一个bean完成多个功能，提高复用性。
 *  适合交给容器进行管理的bean：
    
     *  表现层对象(servlet)
     *  业务层对象(service)
     *  数据层对象(Dao)
     *  工具类对象
 *  不适合交给容器进行管理的bean
    
     *  封装实体的域对象

###### 4：实例化bean的四种方式 ######

###### **4.1：构造方法(常用)** ######

*  需要提供默认构造方法(无参构造方法)
 *  如果无参构造方法不存在，将抛出异常BeanCreationException

###### 4.2:静态工厂(了解) ######

*  静态工厂
    
        public class OrderDaoFactory{
              
            public static OrderDao getOrderDao(){
              
                return new OrderDaoImpl();
            }
        }
 *  配置
    
        <bean
            id="orderDao"
            class="com.my.factory.OrderDaoFactory"
            factory-method="getOrderDao"
        />

###### 4.3:实例工厂(了解) ######

![在这里插入图片描述][e8baa30fe3d04a6f9be24cac784e5cf5.png]

###### 4.4：FactoryBean(实用) ######

*  `BookDaoFactoryBean.java`

public class BookDaoFactoryBean implements FactoryBean<BookDao> {
        
        @Override
        public BookDao getObject() throws Exception {
        
            return new BookDaoImpl();
        }
    
        @Override
        public Class<?> getObjectType() {
        
            return BookDao.class;
        }
    }

*  `配置信息`

<bean id="bookDaoFac" class="com.my.factory.BookDaoFactoryBean"/>

###### 4.5：Bean生命周期 ######

*  初始化容器
    
    1.  创建对象(内存分配)
    2.  执行构造方法
    3.  执行属性注入(set操作)
    4.  执行bean初始化方法
 *  使用Bean
    
    1.  执行业务操作
 *  关闭/销毁容器
    
    1.  执行bean销毁方法
 *  bean生命周期控制
    
     *  配置
        
         *  init-method
         *  destroy-method
     *  接口(了解)
        
         *  InitializingBean
         *  DisposableBean
 *  关闭容器
    
     *  ConfigurableApplicationContext
        
         *  手工关闭容器
            
            ConfigurableApplicationContext接口close()操作
         *  注册关闭钩子，在虚拟机退出前先关闭容器再退出虚拟机
            
            ConfigurableApplicationContext接口registerShutdownHook()操作

![在这里插入图片描述][f4b06228922b4fa8a340f6625097be0e.png]

###### 5：向类传递数据 ######

###### 5.1：依赖注入方式 ######

1.  setter注入
    
     *  简单类型
     *  引用类型
2.  构造器注入
    
     *  简单类型
     *  引用类型

###### 5.2：setter注入 ######

1.  引用类型
    
     *  在bean中定义引用数据类型属性并提供可访问的set方法
        
            private UserDao userDao;
            
            public void setUserDao(UserDao userDao) {
                    
                this.userDao = userDao;
            }
     *  配置中使用**property**标签**ref**属性注入引用类型对象
        
            <bean id="userDao" class="com.my.dao.impl.UserDaoImpl"/>
            <bean id="bookService" class="com.my.service.impl.BookServiceImpl">
                
                
                <property name="userDao" ref="userDao"/>
            </bean>
2.  简单类型
    
     *  在bean中定义引用类型属性并提供可访问的set方法
        
        `BookDaoImpl`
        
            public class BookDaoImpl implements BookDao {
                    
                private int conNum;
                private String dbName;
            
                public void setConNum(int conNum) {
                    
                    this.conNum = conNum;
                }
            
                public void setDbName(String dbName) {
                    
                    this.dbName = dbName;
                }
            
                public void save() {
                    
                    System.out.println("book dao save ..."+conNum+" "+dbName);
                }
            }
     *  配置中使用**property**标签**value**属性注入简单类型数据
        
            <bean id="bookDao" class="com.my.dao.impl.BookDaoImpl">
                
                <property name="conNum" value="10"/>
                <property name="dbName" value="mysql"/>
            </bean>

###### 5.3：构造器注入 ######

1.  引用类型
    
     *  在bean中定义引用数据类型属性并提供可访问的构造方法
        
            private BookDao bookDao;
            private UserDao userDao;
            
            public BookServiceImpl(BookDao bookDao, UserDao userDao) {
                    
                this.bookDao = bookDao;
                this.userDao = userDao;
            }
     *  配置中使用**constructor-arg**标签**ref**属性注入引用类型对象
        
            <bean id="bookService" class="com.my.service.impl.BookServiceImpl">
                
                <constructor-arg name="bookDao" ref="bookDao"/>
                <constructor-arg name="userDao" ref="userDao"/>
            </bean>
2.  简单类型
    
     *  在bean中定义简单数据类型属性并提供可访问的构造方法
        
            private int conNum;
            private String dbName;
            
            public BookDaoImpl(int conNum, String dbName) {
                    
                this.conNum = conNum;
                this.dbName = dbName;
            }
     *  配置中使用**constructor-arg**标签**value**属性注入简单类型对象
        
            <bean id="bookDao" class="com.my.dao.impl.BookDaoImpl">
                <constructor-arg name="conNum" value="10"/>
                <constructor-arg name="dbName" value="mysql"/>
            </bean>
     *  配置中使用**constructor-arg**标签**type**属性设置按照形参**类型**注入
     *  配置中使用**constructor-arg**标签**index**属性设置按照形参**位置**注入

###### 5.4：依赖注入方式选择 ######

![在这里插入图片描述][48aadd2cecf847f28c52ebc04eb31faf.png]

###### 5.5：自动类型的装配 ######

1.  使用bean标签autowire属性设置自动装配的类型(byType、byName(耦合度高，不推荐))
    
        <bean id="bookDao" class="com.my.dao.impl.BookDaoImpl"/>
        <bean id="bookService" class="com.my.service.impl.BookServiceImpl" autowire="byType"/>
        <bean id="bookService" class="com.my.service.impl.BookServiceImpl" autowire="byName"/>
2.  依赖自动装配特征
    
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###### 5.6：注入集合 ######

public class BookDaoImpl implements BookDao {
        
        private int[] array;
        private List<String> list;
        private Set<String> set;
        private Map<String, String> map;
        private Properties properties;
    
        public void setArray(int[] array) {
        
            this.array = array;
        }
    
        public void setList(List<String> list) {
        
            this.list = list;
        }
    
        public void setSet(Set<String> set) {
        
            this.set = set;
        }
    
        public void setMap(Map<String, String> map) {
        
            this.map = map;
        }
    
        public void setProperties(Properties properties) {
        
            this.properties = properties;
        }
    
        public void save() {
        
            System.out.println(Arrays.toString(array));
            System.out.println(list);
            System.out.println(set);
            System.out.println(map);
            System.out.println(properties);
        }
    }

\`\`

<bean id="bookDao" class="com.my.dao.impl.BookDaoImpl">
        <property name="array">
            <array>
                <value>100</value>
                <value>200</value>
                <value>300</value>
            </array>
        </property>
    
        <property name="list">
            <list>
                <value>country</value>
                <value>aaa</value>
                <value>bbb</value>
            </list>
        </property>
    
        <property name="set">
            <set>
                <value>100</value>
                <value>aaa</value>
                
                <value>aaa</value>
                <value>bbb</value>
            </set>
        </property>
    
        <property name="map">
            <map>
                <entry key="country" value="china"/>
                <entry key="province" value="guangdong"/>
                <entry key="city" value="shenzhen"/>
            </map>
        </property>
    
        <property name="properties">
            <props>
                <prop key="country">china</prop>
                <prop key="province">guangdong</prop>
                <prop key="city">guangzhou</prop>
            </props>
        </property>
    </bean>

###### 6：数据源对象管理 ######

###### 6.1：基本配置 ######

6.1.1导入Druid坐标

<dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.16</version>
    </dependency>

6.1.2配置数据源对象作为spring管理的bean

###### 6.2：加载properties文件 ######

6.2.1.开启context名称空间

<beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:context="http://www.springframework.org/schema/context"  
           xsi:schemaLocation="
                http://www.springframework.org/schema/beans
                http://www.springframework.org/schema/beans/spring-beans.xsd
                http://www.springframework.org/schema/context  
                http://www.springframework.org/schema/context/spring-context.xsd">

6.2.2.使用context命名空间，加载指定properties文件

`<context:property-placeholder location="jdbc.properties"/>`

6.2.3.使用$\{\}读取加载的属性值

6.2.4.其他设置

![在这里插入图片描述][eb0f9de87ede4bd1bfd813301d0932f7.png]

6.2.5.加载配置文件

![在这里插入图片描述][0b4bfdf0787a46eba70f9abdea735ab5.png]

6.2.6.容器相关

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6.2.7获取bean

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###### 6.3：注解开发bean ######

6.3.1使用@Componet定义bean

@Component("bookDao")
    public class BookDaoImpl implements BookDao {
        
    }
    
    @Component
    public class BookServiceImpl implements BookService {
        
    }

6.3.2核心配置文件中通过组件扫描加载bean

<context:component-scan base-package="com.my"/>

6.3.3 Spring提供@Component注解的三个衍生注解(与Component功能一样)

@Controller  //用于表现层bean定义
    @Service  //用于业务层定义bean
    @Repository  //用于数据层bean定义

###### 7：纯注解开发: ######

###### 7.1：基本配置 ######

7.1.1：Spring3.0开启了纯注解开发模式，使用Java类替代配置文件，开启了Spring快速开发赛道

7.1.2：Java类代替Spring核心配置文件

`com.my.config.SpringConfig.java`

@Configuration   //用于设定当前类为配置类
    // @ComponentScan("com.my")  
    @ComponentScan({
        "com.my.service","com.my.dao"})  //用于设定扫描路径，只能添加一次，多个数据用数组格式
    public class SpringConfig {
        
    }

7.1.3：读取Spring核心配置文件初始化容器对象切换为读取Java配置类初始化容器对象

public static void main(String[] args) {
        
        ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);
        //获取资源 按bean名称获取
        BookDao bookDao = (BookDao) ctx.getBean("bookDao");
        System.out.println(bookDao);
    
        // 按bean类型获取
        BookService bookService = ctx.getBean(BookService.class);
        System.out.println(bookService);
    }

7.1.4：小结

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###### 7.2：作用范围及生命周期 ######

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###### 7.3：依赖注入 ######

7.3.1：注入引用类型

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7.3.2：简单数据类型

@Value("${}")
    private String name;

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7.3.3：小结

![930f5961003d4280a2d2169bcdbe3358.png][]

###### 7.4：第三方Bean的注入 ######

![在这里插入图片描述][2790ed8d5fc740409c370a75385f096b.png]

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###### 7.5：XML配置VS注解配置 ######

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###### 8：Spring整合Mybatis ######

###### 8.1：jdbcConfig ######

public class jdbcConfig {
        
        @Value("${jdbc.driver}")
        private String driver;
        @Value("${jdbc.url}")
        private String url;
        @Value("${jdbc.username}")
        private String username;
        @Value("${jdbc.password}")
        private String password;
    
        @Bean
        public DataSource dataSource(){
        
            DruidDataSource ds = new DruidDataSource();
            ds.setDriverClassName(driver);
            ds.setUrl(url);
            ds.setUsername(username);
            ds.setPassword(password);
            return ds;
        }

###### 8.2：mybatisConfig ######

public class mybatisConfig {
        
        //替换xml基本配置信息
        @Bean
        public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){
        
            SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
            sqlSessionFactoryBean.setTypeAliasesPackage("com.my.pojo");
            sqlSessionFactoryBean.setDataSource(dataSource);
            return sqlSessionFactoryBean;
        }
    
        //替换
        /*<mappers>
            <package name="com.my.dao"/>
        </mappers>*/
        @Bean
        public MapperScannerConfigurer mapperScannerConfigurer(){
        
            MapperScannerConfigurer msc = new MapperScannerConfigurer();
            msc.setBasePackage("com.my.dao");
            return msc;
        }
    }

###### 8.3：SpringConfig ######

@Configuration
    @ComponentScan("com.my")
    @PropertySource("classpath:jdbc.properties")
    @Import({
        jdbcConfig.class,mybatisConfig.class})
    public class SpringConfig {
        
    }

###### 9：Spring整合Junit ######

###### 9.1：导入坐标 ######

<dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.13</version>
        <scope>test</scope>
    </dependency>
    
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>5.2.20.RELEASE</version>
    </dependency>

###### 9.2：创建junit测试类 ######

@RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = SpringConfig.class)
    public class AccountServiceTest {
        
        @Autowired
        private AccountService accountService;
    
        @Test
        public void testFindById(){
        
            Account ac = accountService.findById(1);
            System.out.println(ac);
        }
    
        @Test
        public void testFindAll(){
        
            for (Account account : accountService.findAll()) {
        
                System.out.println(account);
            }
    
        }
    }

###### 10：AOP(面向切面编程) ######

###### 10.1：基本概念 ######

*  AOP(Aspect Oriented Programming)面向切面编程，一种编程规范，指导开发者如何组织程序结构
    
     *  OOP：面向对象编程
 *  作用：在不惊动原始设计的基础上为其进行功能增强
 *  Spring概念：无侵入式/无入侵式
 *  连接点(JoinPoint)：程序执行过程中的任意位置，粒度为执行方法、抛出异常、设置变量等
    
     *  在SpringAOP中，理解为方法的执行
 *  切入点(Pointcut)：匹配连接点的式子
    
     *  在SpringAOP中，一个切入点可以描述一个具体方法，也可以匹配多个方法
        
         *  一个具体方法：com.my.dao包下的BookDao接口中的无形参无返回值的save()方法
         *  匹配多个方法：所有的save方法，所有以get开头的方法，所有以Dao结尾的接口中的任意方法，所有带有一个参数的方法。
 *  通知(Advice)：在切入点处执行的操作，也就是共性功能
    
     *  在SpringAOP中，功能最终以方法的形式呈现
 *  通知类：定义通知的类
 *  切面(Aspect)：描述通知与切入点的对应关系

###### 10.2：入门案例 ######

10.2.1：导入aop相关坐标

<dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.9.4</version>
    </dependency>

10.2.2：实现dao接口与实现类

@Repository
    public class BookDaoImpl implements BookDao {
        
        public void save() {
        
            System.out.println(System.currentTimeMillis());
            System.out.println("book dao save ...");
        }
    
        @Override
        public void update() {
        
            System.out.println("book dao update...");
        }
    }

10.2.3：定义通知类，制作通知

10.2.4：定义切入点

10.2.5：绑定切入点与通知关系，并指定通知添加到原始连接点的具体执行位置

10.2.6：定义通知类受Spring容器管理，并定义当前类为切面类

@Component   //6.1 定义通知类受Spring容器管理
    @Aspect  //6.2 定义当前类为切面类
    public class MyAdvice {
        
        //4.定义切入点
        @Pointcut("execution(void com.my.dao.BookDao.update())")
        public void pt(){
        }
    
        //3.定义通知类
        @Before("pt()")  //5.绑定切入点与通知关系，并指定通知添加到原始连接点的具体执行位置
        public void before(){
        
            System.out.println(System.currentTimeMillis());
        }
    }

10.2.7：开启Spring对Aop注解驱动支持

@Configuration
    @ComponentScan("com.my")
    @EnableAspectJAutoProxy  //7.开启Spring对Aop注解驱动支持
    public class SpringConfig {
        
    }

10.2.8：其他代码

public class App {
        
        public static void main(String[] args) {
        
            ApplicationContext ctx = new AnnotationConfigApplicationContext(SpringConfig.class);
            BookDao bookDao = ctx.getBean(BookDao.class);
            bookDao.update();
        }
    }

###### 10.3：AOP执行流程 ######

![27013b3742f248fba5217c9bdf6468df.png][]

![f20327f343204dffadb0563591fe769b.png][]

###### 10.4：AOP切入点表达式 ######

![在这里插入图片描述][59994f26df404c268fe09cdbf4b239b8.png]

![5f060e4cbadf46dfbe3115db87d8f360.png][]

###### 10.5：AOP通知 ######

10.5.1：前置通知 **@Before**

10.5.2：后置通知 **@After**

10.5.3：环绕通知(**重点**)  
![在这里插入图片描述][55269aa4f825451bb819e821a7684c0f.png]

![63b1642edef34cb9bedd49c1111d81ea.png][]

●参数ProceedingJoinPoint参数必须放在第一位。

10.5.4：返回后通知(了解) @AfterReturning 原始切入点方法正常执行完毕后运行

10.5.5：抛出异常通知(了解) @AfterThrowing 抛出异常后执行，不抛异常不执行

###### 10.6：执行效率案例 ######

@Component
    @Aspect
    public class ProjectAdvice {
        
        @Pointcut("execution(* com.my.service.*Service.*(..))")
        private void servicePt(){
        }
    
        @Around("ProjectAdvice.servicePt()")
        public void runSpeed(ProceedingJoinPoint pjp) throws Throwable {
        
            //获取执行签名信息
            Signature signature = pjp.getSignature();
            //通过签名获取执行类型(接口名)
            String className = signature.getDeclaringTypeName();
            //通过签名获取执行操作名称(方法名)
            String methodName = signature.getName();
            long start = System.currentTimeMillis();
            for (int i = 0; i < 10000; i++) {
        
                Object ret = pjp.proceed();
            }
            long end = System.currentTimeMillis();
            System.out.println("执行"+className+"."+methodName+"万次耗时"+(end-start)+"ms");
        }
    }

###### 10.7：AOP通知获取数据 ######

10.7.1：获取参数

![9c61a2241d68488cbfb44f6223ccee38.png][]

10.7.2：获取返回值

![6dfd9186889942f89652e84da1a3eb2c.png][]

###### 11：Spring事务 ######

###### 11.1：开启事务步骤 ######

![dc3054340cca4ef19946b522e961c256.png][]  
![在这里插入图片描述][8aaa5827a9e64324bc0e2feb0fb31902.png]

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###### 11.2：事务角色 ######

![c54126d9fcf34d5cabc5e103c5998e5d.png][]

###### 11.3：事务配置&传播行为 ######

11.3.1：事务配置

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11.3.2：事务传播

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11.3.3：案例

1.  `在jdbcConfig中添加事务管理器`

//设置事务管理器
    @Bean
    public PlatformTransactionManager transactionManager(DataSource dataSource){
        
        DataSourceTransactionManager ptm = new DataSourceTransactionManager();
        ptm.setDataSource(dataSource);
        return ptm;
    }

1.  `在SpringConfig中开启事务支持`

@Configuration
    @ComponentScan("com.my")
    @PropertySource("classpath:jdbc.properties")
    @Import({
        jdbcConfig.class,mybatisConfig.class})
    @EnableAspectJAutoProxy   //开启Spring对Aop注解驱动的支持
    @EnableTransactionManagement //开启事务支持
    public class SpringConfig {
        
    }

1.  `Dao层操作`

//数据层操作
    public interface AccountDao {
        
        @Update("update tbl_account set money = money + #{money} where name = #{name}")
        void inMoney(@Param("name")String name,@Param("money")Double money);
    
        @Update("update tbl_account set money = money - #{money} where name = #{name}")
        void outMoney(@Param("name") String name,@Param("money") Double money);
    }

public interface LogDao {
        
        @Insert("insert into tbl_log(info,createDate) values(#{info},now())")
        void log(String info);
    }

1.  `Service层`

public interface AccountService {
        
        @Transactional
        public void transfer(String out,String in,Double money);
    }

public interface LogService {
        
        //propagation设置事务属性：传播行为设置为当前操作需要新事务
        @Transactional(propagation = Propagation.REQUIRES_NEW)
        void log(String out,String in,Double money);
    
    }

@Service
    public class AccountServiceImpl implements AccountService {
        
        @Autowired
        private AccountDao accountDao;
    
        @Autowired
        private LogService logService;
    
        @Override
        public void transfer(String out, String in, Double money) {
        
            try{
        
                accountDao.outMoney(out,money);
                int a = 1/0;
                accountDao.inMoney(in,money);
            }finally {
        
                logService.log(out,in,money);
            }
        }
    }

@Service
    public class LogServiceImpl implements LogService {
        
        @Autowired
        private LogDao logDao;
        @Override
        public void log(String out, String in, Double money) {
        
            logDao.log(out+"向"+in+"转账"+money+"钱");
        }
    }

1.  `Test`

@RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration(classes = SpringConfig.class)
    public class AccountServiceTest {
        
        @Autowired
        AccountService accountService;
    
        @Test
        public void transferTest(){
        
            accountService.transfer("Tom","Jerry",100D);
        }
    }

##### 三：SpringMVC #####

###### 1：概述 ######

*  SpringMVC是一种基于Java实现MVC模型的轻量级Web框架
 *  优点
    
     *  使用简单，开发便捷(相比于Servlet)
     *  灵活性强

###### 2：快速入门 ######

2.1：导入坐标

<dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
    
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.2.10.RELEASE</version>
        </dependency>
    </dependencies>

2.2：初始化SpringMVC环境

@Configuration
    @ComponentScan("com.my")   //设定SpringMVC加载对应bean
    public class SpringMVCConfig {
        
    }

2.3：创建SpringMVC控制器类(等同于Servlet功能)

@Controller
    public class UserController {
        
        @RequestMapping("/save")  //设置当前控制器方法请求访问路径
        @ResponseBody   //设置当前控制器方法响应内容为当前返回值，无需解析
        public String save(){
        
            System.out.println("user save...");
            return "{'info':'springmvc'}";
        }
    }

2.4：初始化Servlet容器，加载SpringMVC环境，并设置SpringMVC请求拦截的路径

//AbstractDispatcherServletInitializer类是SpringMVC提供的快速初始化Web3.0容器的抽象类
    public class ServletContainersInitConfig extends AbstractDispatcherServletInitializer {
        
        //初始化容器并注册返回容器到Tomcat中，以便可以访问bean
        @Override
        protected WebApplicationContext createServletApplicationContext() {
        
            AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
            ctx.register(SpringMVCConfig.class);
            return ctx;
        }
    
        //设定SpringMVC对应的请求映射路径，设置为/表示拦截所有请求，任意请求都将转入到SpringMVC进行处理
        @Override
        protected String[] getServletMappings() {
        
            return new String[]{
        "/"};
        }
    
        //如果创建Servlet容器时需要加载非SpringMVC对应的bean，使用当前方法进行，使用方式同createServletApplicationContext()
        @Override
        protected WebApplicationContext createRootApplicationContext() {
        
            return null;
        }
    }

###### 3:Controller加载控制与业务Bean加载控制 ######

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###### 4：URL传递参数 ######

*  正常情况下名称对名称
    
     *  普通参数 save(String name,int age)
     *  封装对象 save(User user)
     *  数组 save(String\[\] array)
        
        参数设置 array 10、array 20…
 *  名称对不上用@RequestParam
    
     *  集合 save(@RequestParam List list)
        
        参数设置 list 10、list 20…

###### 5：JSON数据传递参数 ######

5.1：添加JSON数据转换坐标

<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.12.6.1</version>
    </dependency>

5.2：在body中设置JSON数据并发送

5.3：开启自动转换JSON数据的支持

@Configuration
    @ComponentScan("com.my")
    @EnableWebMvc    //开启自动转换JSON数据的支持，开启SpringMVC多项辅助功能
    public class SpringMVCConfig {
        
    }

5.4：设置接收JSON数据

@Controller
    public class UserController {
        
        @ResponseBody  //将请求中请求体所包含的数据传递给请求参数，此注解一个方法只能使用一次
        @RequestMapping("/listParamForJson")
        public String listParamForJson(@RequestBody List<String> likes){
        
            System.out.println("list common(json)参数传递==>" + likes);
            return "{'info':'springmvc'}";
        }

![289ea69ca80e4698a456b73d8aceb5ad.png][]

###### 6：日期类型参数传递 ######

*  dataParam(Date date, //2020/2/12
    
    @DateTimeFormat(pattern=“yyyy-MM-dd”) Date date1, //2020-5-17
    
    @DateTimeFormat(pattern=“yyyy/MM/dd HH:mm:ss”) Date date2 //2020/02/20 20:20:20
    
    )

###### 7：响应 ######

//响应页面/跳转页面
    @RequestMapping("/toJumpPage")
    public String toJumpPage(){
        
        System.out.println("跳转页面");
        return "page.jsp";
    }
    
    //响应纯文本数据
    @RequestMapping("/toText")
    @ResponseBody
    public String toText(){
        
        System.out.println("返回纯文本数据");
        return "response text";
    }
    
    //响应POJO对象
    @RequestMapping("/toJsonPOJO")
    @ResponseBody
    public User toJsonPOJO(){
        
        System.out.println("返回json对象数据");
        User user = new User();
        user.setName("Tom");
        user.setAge(20);
        return user;
    }
    
    //响应POJO集合对象
    @RequestMapping("/toJsonList")
    @ResponseBody
    public List<User> toJsonList(){
        
        System.out.println("返回JSON集合数据");
        User user1 = new User();
        user1.setName("Tom");
        user1.setAge(15);
    
        User user2 = new User();
        user2.setName("Jerry");
        user2.setAge(18);
    
        User user3 = new User();
        user3.setName("Jack");
        user3.setAge(20);
    
        List<User> users = new ArrayList<>();
        users.add(user1);
        users.add(user2);
        users.add(user3);
        return users;
    }

###### 8：REST ######

8.1：概述

![8b79830590274f38a98dcec6e43bbc9d.png][]

![ff4166c6bf1b4eeaa4ffd66b927b242f.png][]

![8f1bbd609dd74f46a2300441a13fc702.png][]

8.2：REST风格案例

// REST/POST
    @RequestMapping(value = "/users", method = RequestMethod.POST)
    @ResponseBody
    public String save() {
        
        System.out.println("user save...");
        return "{'module':'user save'}";
    }
    
    @RequestMapping(value = "/users/{id}",method = RequestMethod.DELETE)
    @ResponseBody
    public String delete(@PathVariable Integer id) {
        
        System.out.println("user delete..."+id);
        return "{'module':'user delete'}";
    }
    
    @RequestMapping(value = "/users",method = RequestMethod.PUT)
    @ResponseBody
    public String update(@RequestBody User user){
        
        System.out.println("user update..."+user);
        return "{'module':'user update'}";
    }
    
    //查询
    @RequestMapping(value = "/users/{id}",method = RequestMethod.GET)
    @ResponseBody
    public String getById(@PathVariable Integer id){
        
        System.out.println("user getById..."+id);
        return "{'module':'user getById'}";
    }

8.3：简化

/**
     * 简化REST
     */
    @RestController("/book")
    public class BookController {
        
        // REST/POST
        @PostMapping
        public String save() {
        
            System.out.println("book save...");
            return "{'module':'book save'}";
        }
    
        @DeleteMapping("/{id}")
        public String delete(@PathVariable Integer id) {
        
            System.out.println("book delete..."+id);
            return "{'module':'book delete'}";
        }
        
        @PutMapping
        public String update(@RequestBody Book book){
        
            System.out.println("book update..."+book);
            return "{'module':'book update'}";
        }
    
        //查询
        @GetMapping("/{id}")
        public String getById(@PathVariable Integer id){
        
            System.out.println("book getById..."+id);
            return "{'module':'book getById'}";
        }
        
        @GetMapping
        public String getAll(){
        
            System.out.println("book getAll...");
            return "{'module':'book getAll'}";
        }
    }

8.4：设置对静态资源的放行

public class SpringMvcSupport extends WebMvcConfigurationSupport {
        
        @Override
        protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        
            //当访问/pages/???时候，走pages目录下的内容，防止被SpringMVC拦截
            registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
            registry.addResourceHandler("/js/**").addResourceLocations("/js/");
            registry.addResourceHandler("/css/**").addResourceLocations("/css/");
            registry.addResourceHandler("/plugins/**").addResourceLocations("/plugins/");
        }
    }

###### 9：表现层返回结果规范化处理 ######

9.1：在controller定义Result类

public class Result {
        
        private Object data;   //返回数据
        private Integer code;  //返回结果代码
        private String msg;   //消息

9.2：定义返回代码

`com.my.controller.Code.java`

public class Code {
        
        public static final Integer SAVE_OK = 20011;
        public static final Integer DELETE_OK = 20021;
        public static final Integer UPDATE_OK = 20031;
        public static final Integer GET_OK = 20041;
    
        public static final Integer SAVE_ERR = 20010;
        public static final Integer DELETE_ERR = 20020;
        public static final Integer UPDATE_ERR = 20030;
        public static final Integer GET_ERR = 20040;
    
    }

9.3：修改表现层返回类型

@GetMapping
    public Result getAll() {
        
        List<Book> bookList = bookService.getAll();
        Integer code = (bookList == null ? Code.GET_ERR:Code.GET_OK);
        String msg = (bookList == null? "数据查询失败！":"");
        return new Result(code,bookList,msg);
    }

###### 10：异常处理 ######

10.1：集中处理

`com.my.controller.ProjectExceptionAdvice.java`

@RestControllerAdvice   //将类声明为异常处理类
    public class ProjectExceptionAdvice {
        
        @ExceptionHandler(Exception.class)  //定义处理哪一种异常
        public Result doException(Exception ex){
        
            return new Result(11111,null,"捕捉到异常！");
        }
    }

10.2：异常分类

*  业务异常(BusinessException)
    
     *  规范的用户行为产生的异常
     *  不规范的用户行为操作产生的异常
 *  系统异常(SystemException)
    
     *  项目运行过程中可预计且无法避免的异常
 *  其他异常(Exception)
    
     *  编程人员未预期到的异常

10.3：异常分类处理

10.3.1：定义Result返回体

`com.my.controller.Result.java`

public class Result {
        
        private Object data;   //返回数据
        private Integer code;  //返回结果代码
        private String msg;   //消息

10.3.2：定义异常编码

package com.my.controller;
    
    public class Code {
        
        public static final Integer SAVE_OK = 20011;
        public static final Integer DELETE_OK = 20021;
        public static final Integer UPDATE_OK = 20031;
        public static final Integer GET_OK = 20041;
    
        public static final Integer SAVE_ERR = 20010;
        public static final Integer DELETE_ERR = 20020;
        public static final Integer UPDATE_ERR = 20030;
        public static final Integer GET_ERR = 20040;
    
        public static final Integer SYSTEM_ERR = 50001;
        public static final Integer SYSTEM_TIMEOUT_ERR = 50002;
        public static final Integer SYSTEM_UNKNOWN_ERR = 59999;
        public static final Integer BUSINESS_ERR = 60002;
    }

10.3.3：定义异常类

package com.my.exception;
    
    public class BusinessException extends RuntimeException{
        
        private Integer code;
    
        public Integer getCode() {
        
            return code;
        }
    
        public void setCode(Integer code) {
        
            this.code = code;
        }
    
        public BusinessException(Integer code, String message) {
        
            super(message);
            this.code = code;
        }
    
        public BusinessException(Integer code, String message, Throwable cause) {
        
            super(message, cause);
            this.code = code;
        }
    }

package com.my.exception;
    
    public class SystemException extends RuntimeException{
        
        private Integer code;
    
        public Integer getCode() {
        
            return code;
        }
    
        public void setCode(Integer code) {
        
            this.code = code;
        }
    
        public SystemException(Integer code, String message) {
        
            super(message);
            this.code = code;
        }
    
        public SystemException(Integer code, String message, Throwable cause) {
        
            super(message, cause);
            this.code = code;
        }
    }

10.3.4：定义异常处理类

package com.my.controller;
    
    import com.my.exception.BusinessException;
    import com.my.exception.SystemException;
    import org.springframework.web.bind.annotation.ExceptionHandler;
    import org.springframework.web.bind.annotation.RestControllerAdvice;
    
    /**
     * 处理异常
     */
    @RestControllerAdvice   //将类声明为异常处理类
    public class ProjectExceptionAdvice {
        
        @ExceptionHandler(SystemException.class)  //定义处理哪一种异常
        public Result doSystemException(SystemException ex){
        
            //记录日志
            //发送消息给运维
            //发送邮件给开发人员，ex对象发送给开发人员
            return new Result(ex.getCode(),null,ex.getMessage());
        }
    
        @ExceptionHandler(BusinessException.class)  //定义处理哪一种异常
        public Result doBusinessException(BusinessException ex){
        
            return new Result(ex.getCode(),null,ex.getMessage());
        }
    
        @ExceptionHandler(Exception.class)  //定义处理哪一种异常
        public Result doException(Exception ex){
        
            //记录日志
            //发送消息给运维
            //发送邮件给开发人员，ex对象发送给开发人员
            return new Result(Code.SYSTEM_UNKNOWN_ERR,null,"系统繁忙，请稍后再试!");
        }
    }

10.3.5：捕捉异常

`com.my.controller.BookController.java`

@GetMapping(value = ("/getById"))
    public Result getById(@RequestParam("id") Integer id) {
        
        if(id == 0){
        
            throw new BusinessException(Code.BUSINESS_ERR,"请规范您的操作!");
        }
        //将可能出现的异常进行包装，转换成自定义异常
        try{
        
            int i = 1/0;
        }catch (Exception e){
        
            throw new SystemException(Code.SYSTEM_TIMEOUT_ERR,"服务器访问超时，请稍后再试!",e);
        }
        Book book = bookService.getById(id);
        Integer code = (book == null? Code.GET_ERR:Code.GET_OK);
        String msg = (book == null? "数据查询失败！":"");
        return new Result(code,book,msg);
    }

###### 11：拦截器 ######

11.1：声明拦截器的bean，并实现HandlerInterceptor接口(注意：扫描加载bean)

package com.my.controller.interceptor;
    
    import org.springframework.stereotype.Component;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    @Component
    public class ProjectInterceptor implements HandlerInterceptor {
        
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        
            System.out.println("preHandle...");
            return true;
        }
    
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        
            System.out.println("postHandle...");
        }
    
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        
            System.out.println("afterCompletion...");
        }
    }

11.2：定义配置类，继承WebMvcConfigurationSupport，实现addInterceptor方法(注意：扫描加载配置)

`package com.my.config;`

@Configuration
    public class SpringMvcSupport extends WebMvcConfigurationSupport {
        
        //设置过滤静态访问资源
        @Override
        protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        
            registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
            registry.addResourceHandler("/css/**").addResourceLocations("/css/");
            registry.addResourceHandler("/js/**").addResourceLocations("/js/");
            registry.addResourceHandler("/plugins/**").addResourceLocations("/plugins/");
        }
    
        //自动装配拦截器
        @Autowired
        private ProjectInterceptor projectInterceptor;
        
        //添加拦截器
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
        
            registry.addInterceptor(projectInterceptor).addPathPatterns("/books","/books/*");  //设置具体拦截路径,可设置多个
        }
    }

11.3：添加扫描路径

@Configuration
    @ComponentScan({
        "com.my.controller","com.my.config"})
    @EnableWebMvc
    public class SpringMvcConfig {
        
    }

11.4：简化(注意：侵入式较强)

`com.my.config.SpringMvcConfig.java`

@Configuration
    @ComponentScan({
        "com.my.controller"})
    @EnableWebMvc
    public class SpringMvcConfig implements WebMvcConfigurer {
        
        //自动装配拦截器
        @Autowired
        private ProjectInterceptor projectInterceptor;
    
        //添加拦截器
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
        
            registry.addInterceptor(projectInterceptor).addPathPatterns("/books","/books/*");  //设置具体拦截路径
        }
    }

11.5：执行流程

![bbdf48bc74374326a6049e7abb0b1951.png][]

11.6：拦截器参数

![84e2d8ef19c840a8ae4584ca0f0b2a84.png][]

11.7：拦截器链

![16a5e2d7965446498ae90c9d8d317307.png][]

##### 四：Maven高级 #####

###### 1：分模块开发 ######

1.1：创建Maven模块

1.2：书写模块代码

1.3：通过Maven指令安装模块到本地仓库(install指令)

###### 2：可选依赖于排除依赖 ######

2.1：可选依赖

true

指对外隐藏当前所依赖的资源----不透明

2.2：排除依赖

指主动断开依赖的资源，被排除的资源无需指定版本-------不需要

###### 3：多环境配置与应用 ######

3.1：多环境

![1b876b01a8ab466bb4a420dbcd11347f.png][]

![34a3bdeb75ed46e8b10ad71e15c6aed8.png][]

3.2：跳过测试

![fc04925699204a16b1562a89810b89d3.png][]

![04fc714e204c4d7e811c8f4b5a520dbb.png][]

###### 4：yml文件读取 ######

![6432f2568cb6406ab25493679976aa63.png][]

![647878c9c19c402ab31bd2b77ac379d1.png][]

![95bf4cb38bf24c70803413dfc99650e4.png][]

![6c3bccfd827a47b7b63a70041206791d.png][]

##### 五：SpringBoot&MybatisPlus #####

###### 1：快速入门 ######

1.1：导入坐标

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.7.0</version>
        </parent>
        <groupId>com.my</groupId>
        <artifactId>MybatisPlus-demo1</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>MybatisPlus-demo1</name>
        <description>MybatisPlus-demo1</description>
        <properties>
            <java.version>11</java.version>
        </properties>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <optional>true</optional>
                <scope>provided</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.1.16</version>
            </dependency>
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>3.5.0</version>
            </dependency>
        </dependencies>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <configuration>
                        <excludes>
                            <exclude>
                                <groupId>org.projectlombok</groupId>
                                <artifactId>lombok</artifactId>
                            </exclude>
                        </excludes>
                    </configuration>
                </plugin>
            </plugins>
        </build>
    
    </project>

1.2：创建配置文件(注意空格)

`application.yml`

spring:
      datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://localhost:3306/ssm_db
        username: root
        password: 440983

1.3：创建Book及BookDao

@Data    //添加Lombok注解
    public class Book {
        
        private int id;
        private String type;
        private String name;
        private String description;
    }
    
    @Mapper
    public interface BookDao extends BaseMapper<Book> {
        
    }

*  说明：@Data注解为当前实体类在编译期设置对应的get/set方法，toString方法、hashCode方法、equals方法等
 *  要注意数据库中表的名称要为book

1.4：测试

@SpringBootTest
    class ApplicationTests {
        
        @Autowired
        private BookDao bookDao;
    
        @Test
        void getByIdTest() {
        
            Book book = bookDao.selectById(1);
            System.out.println(book);
        }
    
        @Test
        void updateTest(){
        
            Book book = new Book();
            book.setId(1);
            book.setDescription("操作系统从入门到入坟");
            int i = bookDao.updateById(book);
            System.out.println(i);
        }
        
        
            bookDao.selectBatchIds(List);   
        -->
    }

![b9814126c7884f0ba19417c4ea990f76.png][]

###### 2：分页查询 ######

2.1：设置分页拦截器作为Spring管理的bean

@Configuration
    public class MpConfig {
        
        @Bean
        public MybatisPlusInterceptor pageInterceptor(){
        
            MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
            interceptor.addInnerInterceptor(new PaginationInnerInterceptor());
            return interceptor;
        }
    }

2.2：执行分页查询

public void pageTest(){
        
        IPage<Book> page = new Page<Book>(1, 3);
        bookDao.selectPage(page,null);
        System.out.println("当前页码："+page.getCurrent());
        System.out.println("每页数据总量："+page.getSize());
        System.out.println("总页数："+page.getPages());
        System.out.println("数据总量："+page.getTotal());
        System.out.println("当前页数据："+page.getRecords());
    }

###### 3：条件查询 ######

//条件查询
    @Test
    public void getAllTest(){
        
        //方式一：按条件查询
        QueryWrapper<Book> qw = new QueryWrapper<Book>();
        qw.lt("id",6);    //小于
        for (Book book : bookDao.selectList(qw)) {
        
            System.out.println(book);
        }
    
        //方式二：lambda格式
        QueryWrapper<Book> qw = new QueryWrapper<Book>();
        qw.lambda().lt(Book::getId,6);
        for (Book book : bookDao.selectList(qw)) {
        
            System.out.println(book);
        }
    
        //方式三(推荐)
        LambdaQueryWrapper<Book> lqw = new LambdaQueryWrapper<Book>();
        lqw.lt(Book::getId,6);
        for (Book book : bookDao.selectList(lqw)) {
        
            System.out.println(book);
        }
    
        //多条件查询
        LambdaQueryWrapper<Book> lqw = new LambdaQueryWrapper<Book>();
        //4到10之间
        // lqw.lt(Book::getId,10).gt(Book::getId,4);
        //小于4或者大于10
        lqw.lt(Book::getId,4).or().gt(Book::getId,10);
        for (Book book : bookDao.selectList(lqw)) {
        
            System.out.println(book);
        }
        
        /*----------------------------------------NULL判定---------------------------------*/
        LambdaQueryWrapper<Book> lqw = new LambdaQueryWrapper<Book>();
        BookQuery bookQuery = new BookQuery();
        bookQuery.setId(10);
        bookQuery.setId2(5);
        //lt 小于，le 小于等于
        //gt 大于，ge 大于等于
        //链式编程
        /* 
        lqw.lt(null != bookQuery.getId(),Book::getId,bookQuery.getId())
        .gt(null != bookQuery.getId2(),Book::getId,bookQuery.getId2());
        */
        lqw.lt(null != bookQuery.getId(),Book::getId,bookQuery.getId());
        lqw.gt(null != bookQuery.getId2(),Book::getId,bookQuery.getId2());
        for (Book book : bookDao.selectList(lqw)) {
        
            System.out.println(book);
        }
        
        /*----------------------------查询投影---------------------------------*/
        //查询结果包含模型中部分属性
        LambdaQueryWrapper<Book> lqw = new LambdaQueryWrapper<Book>();
        //查询id、书名、描述
        lqw.select(Book::getId,Book::getName,Book::getDescription);
        List<Book> bookList = bookDao.selectList(lqw);
        bookList.forEach(System.out::println);
        
        
        //查询结果包含模型中未定义的属性
        QueryWrapper<Book> qw = new QueryWrapper<>();
        /* qw.select("id","name","description");
        for (Book book : bookDao.selectList(qw)) {
            System.out.println(book);
        } */
        qw.select("count(*) as nums,type");
        qw.groupBy("type");
        List<Map<String, Object>> maps = bookDao.selectMaps(qw);
        System.out.println(maps);
        
        /*-------------------------其他查询---------------------------------*/
        lqw.between(Book::getId,10,20);    //查询id在10到20之间，包含10和20
        lqw.like("计算机");			//like %计算机%
        lqw.likeLeft("计算机");		//like %计算机
        lqw.likeRigt("计算机");		//like 计算机%
    }

###### 4：映射匹配兼容性 ######

@Data    //添加Lombok注解
    @TableName("tbl_book")   //设置当前类与数据库表之间的对应关系
    public class Book {
        
        private Integer id;
        @TableField(value = "type",select = false)   //value设置数据库表段名称，select：设置是否参与查询
        private String Type;
        private String name;
        private String description;
    
        @TableField(exist = false)   //设置属性在数据库表段中是否存在，默认为true，此属性无法与value合并使用
        private Integer isON;
    }

*  全局配置
    
        mybatis-plus:
          global-config:
            db-config:
              id-type: auto    
              table-prefix: tbl_

###### 5：逻辑查询 ######

5.1：数据库添加字段用于表示是否删除(注意尽量不要用关键字作为字段名)

5.2：用yml文件全局配置

mybatis-plus:
      global-config:
        banner: false
        db-config:
          logic-delete-field: is_delete   #设置表示逻辑删除的字段
          logic-delete-value: 1        #设置表示删除的值
          logic-not-delete-value: 0    #设置表示未删除的值

5.3：pojo类添加相应属性

// @TableLogic(value = "0",delval = "1")
    private Integer is_delete;     //表示逻辑删除

5.4：执行删除操作

@Test
    void deleteTest(){
        
        bookDao.deleteById(3);
    }

\[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-ku5rodfz-1653122017080)(SSM笔记.assets/image-20220521115510938.png)\]

*  注意这时执行的是UPDATE操作  
    Book::getId,Book::getName,Book::getDescription);  
    List bookList = bookDao.selectList(lqw);  
    bookList.forEach(System.out::println);
    
    //查询结果包含模型中未定义的属性  
    QueryWrapper qw = new QueryWrapper<>();  
    /\* qw.select(“id”,“name”,“description”);  
    for (Book book : bookDao.selectList(qw)) \{  
    System.out.println(book);  
    \} */  
    qw.select("count(*) as nums,type");  
    qw.groupBy(“type”);  
    List<Map<String, Object>> maps = bookDao.selectMaps(qw);  
    System.out.println(maps);
    
    /*-------------------------其他查询---------------------------------*/  
    lqw.between(Book::getId,10,20); //查询id在10到20之间，包含10和20  
    lqw.like(“计算机”); //like %计算机%  
    lqw.likeLeft(“计算机”); //like %计算机  
    lqw.likeRigt(“计算机”); //like 计算机%  
    \}

###### 4：映射匹配兼容性
    
    ```java
    @Data    //添加Lombok注解
    @TableName("tbl_book")   //设置当前类与数据库表之间的对应关系
    public class Book {
        private Integer id;
        @TableField(value = "type",select = false)   //value设置数据库表段名称，select：设置是否参与查询
        private String Type;
        private String name;
        private String description;
    
        @TableField(exist = false)   //设置属性在数据库表段中是否存在，默认为true，此属性无法与value合并使用
        private Integer isON;
    }

###### 5：逻辑查询 ######

5.1：数据库添加字段用于表示是否删除(注意尽量不要用关键字作为字段名)

5.2：用yml文件全局配置

5.3：pojo类添加相应属性

// @TableLogic(value = "0",delval = "1")
    private Integer is_delete;     //表示逻辑删除

5.4：执行删除操作

@Test
    void deleteTest(){
        
        bookDao.deleteById(3);
    }

![\[外链图片转存中...(img-ku5rodfz-1653122017080)\]][..._img-ku5rodfz-1653122017080]

*  注意这时执行的是UPDATE操作

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