个人项目总结(一)

╰半橙微兮° 2022-02-25 00:04 205阅读 0赞

# SpringDataJp #

## 1. 集成Spring+SpringDataJpa ##

1）引入相关jar包(项目所有包)

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
            <modelVersion>4.0.0</modelVersion>
        
            <groupId>cn.itsource</groupId>
            <artifactId>springdatajpa</artifactId>
            <version>1.0-SNAPSHOT</version>
        
            <properties>
                <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
                <org.springframework.version>4.2.5.RELEASE</org.springframework.version>
                <org.hibernate.version>4.3.8.Final</org.hibernate.version>
                <spring-data-jpa.version>1.9.0.RELEASE</spring-data-jpa.version>
                <com.fasterxml.jackson.version>2.5.0</com.fasterxml.jackson.version>
            </properties>
            <dependencies>
                
                <dependency>
                   <groupId>org.springframework</groupId>
                   <artifactId>spring-core</artifactId>
                   <version>${org.springframework.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-context</artifactId>
                    <version>4.2.5.RELEASE</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-tx</artifactId>
                    <version>${org.springframework.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-jdbc</artifactId>
                    <version>${org.springframework.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-orm</artifactId>
                    <version>${org.springframework.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-aop</artifactId>
                    <version>${org.springframework.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-test</artifactId>
                    <version>${org.springframework.version}</version>
                    <scope>test</scope>
                </dependency>
                
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-web</artifactId>
                    <version>${org.springframework.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.springframework</groupId>
                    <artifactId>spring-webmvc</artifactId>
                    <version>${org.springframework.version}</version>
                </dependency>
                
                <dependency>
                    <groupId>org.apache.commons</groupId>
                    <artifactId>commons-io</artifactId>
                    <version>1.3.2</version>
                </dependency>
                
                <dependency>
                    <groupId>commons-fileupload</groupId>
                    <artifactId>commons-fileupload</artifactId>
                    <version>1.2.2</version>
                </dependency>
                
                <dependency>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-core</artifactId>
                    <version>${com.fasterxml.jackson.version}</version>
                </dependency>
                <dependency>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-annotations</artifactId>
                    <version>${com.fasterxml.jackson.version}</version>
                </dependency>
                <dependency>
                    <groupId>com.fasterxml.jackson.core</groupId>
                    <artifactId>jackson-databind</artifactId>
                    <version>${com.fasterxml.jackson.version}</version>
                </dependency>
                
                <dependency>
                    <groupId>org.hibernate</groupId>
                    <artifactId>hibernate-core</artifactId>
                    <version>${org.hibernate.version}</version>
                </dependency>
                <dependency>
                    <groupId>org.hibernate</groupId>
                    <artifactId>hibernate-entitymanager</artifactId>
                    <version>${org.hibernate.version}</version>
                </dependency>
                
                <dependency>
                    <groupId>org.springframework.data</groupId>
                    <artifactId>spring-data-jpa</artifactId>
                    <version>${spring-data-jpa.version}</version>
                </dependency>
                
                <dependency>
                    <groupId>com.github.wenhao</groupId>
                    <artifactId>jpa-spec</artifactId>
                    <version>3.1.1</version>
                    
                    <exclusions>
                        <exclusion>
                            <groupId>*</groupId>
                            <artifactId>*</artifactId>
                        </exclusion>
                    </exclusions>
                </dependency>
        
                <dependency>
                    <groupId>commons-dbcp</groupId>
                    <artifactId>commons-dbcp</artifactId>
                    <version>1.2.2</version>
                </dependency>
        
                <dependency>
                    <groupId>mysql</groupId>
                    <artifactId>mysql-connector-java</artifactId>
                    <version>5.1.6</version>
                </dependency>
        
                <dependency>
                    <groupId>org.apache.commons</groupId>
                    <artifactId>commons-lang3</artifactId>
                    <version>3.5</version>
                </dependency>
                
                <dependency>
                    <groupId>junit</groupId>
                    <artifactId>junit</artifactId>
                    <version>4.12</version>
                    <scope>test</scope>
                </dependency>
                <dependency>
                    <groupId>javax.servlet</groupId>
                    <artifactId>javax.servlet-api</artifactId>
                    <version>3.1.0</version>
                    
                    <scope>provided</scope>
                </dependency>
            </dependencies>
        </project>

2）配置applicationContext.xml

<context:component-scan base-package="cn.itsource.aisell.service" />
         <context:property-placeholder location="classpath:jdbc.properties" />
         
         <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
     destroy-method="close">
             
             <property name="driverClassName" value="${jdbc.driverClassName}" />
             <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
             <property name="password" value="${jdbc.password}" />
             
             <property name="maxActive" value="150" />
             
             <property name="minIdle" value="5" />
             
             <property name="maxIdle" value="20" />
    
             <property name="initialSize" value="30" />
             
             
             <property name="logAbandoned" value="true" />
             
             <property name="removeAbandoned" value="true" />
             
    <property name="removeAbandonedTimeout" value="10" />
             
             <property name="maxWait" value="1000" />
             
             <property name="timeBetweenEvictionRunsMillis" value="10000" />
             
             <property name="numTestsPerEvictionRun" value="10" />
             
             <property name="minEvictableIdleTimeMillis" value="10000" />
             <property name="validationQuery" value="SELECT NOW() FROM DUAL" />
         </bean>
         
         <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
             <property name="dataSource" ref="dataSource" />
             
             <property name="packagesToScan" value="cn.itsource.aisell.domain" />
            
             
             <property name="jpaVendorAdapter">
                 <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                     
                     
                     <property name="showSql" value="true" />
                     
                     <property name="generateDdl" value="false" />
                     
                     <property name="databasePlatform" value="org.hibernate.dialect.MySQLDialect" />
                 </bean>
             </property>
         </bean>
         
         <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
             <property name="entityManagerFactory" ref="entityManagerFactory" />
         </bean>
         
         <tx:annotation-driven />
     
         
         
    <jpa:repositories base-package="cn.itsource.pss.repository" transaction-manager-ref="transactionManager"
                           entity-manager-factory-ref="entityManagerFactory" /><beans>

3）准备Domain

@Entity
    			@Table(name="employee")
    			public class Employee extends  BaseDomain {
    		    private String username;
    		    private String password;
    		    private String email; 
    		    private Integer age;
    		   //省略getter,setter与toString(注意:Alt+Insert可以自动生成) 			}

4）完成Repository的功能

package cn.itsource.pss.repository;
    
    import cn.itsource.pss.domain.Employee; import org.springframework.data.jpa.repository.JpaRepository;
    
    /**  * 必需继续JpaRepository<1v,2v>  *     1v:代表你要操作的是哪一个domain对象  *     2v:这个domain对象的主键的类型  */
    public interface EmployeeRepository extends JpaRepository<Employee, Long> { }

## 2. SpringDataJpa认识使用 ##

1） SpringDataJpa是JPA规范的再次封装底层还是使用了Hibernate的JPA技术实现，引用JPQL的查询语句  
2） 简化创建 JPA 数据访问层和跨存储的持久层功能  
3）ORM框架：对象关系映射(JPA)  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70]4) SimpleJpaRepository类实现了JpaRepository接口和JpaSpecificationExecutor接口，  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 1]  
而SpringDataJpa自动创建了一个代理类proxy，实现了我们自己写的EmployeeRepository接口，同时继承了SimpleJpaRepository类

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 2]

## 3. JpaRepository基本功能 ##

1）分页：

Pageable  page = new PageRequest(page,size); 			
    employeeRepository.findAll(page);

2）排序：

Sort   sort   = new   Sort(Sort.Direction.DESC,"age"); 			
    employeeRepository.findAll(sort);

3）分页排序：

Pageable  page = new PageRequest(page,size,sort); 			
    employeeRepository.findAll(sort);

4)高级查询(继承了JpaRepository的接口中)：

① List  findByUsername(String username); //根据用户名Username查询 			 
    ② List  findByUsernameLike(String username);//根据用户名模糊查询 			
    ③ List  findByUsernameLikeAndEmailLike(String username,String email);//多条件模糊查询

之所以可以用以上方法查询，是因为SpringDataJpa准备的一套规范  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 3]![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 4]  
5) 复杂的查询SpringDataJpa规范无法使用，需要自己写sql

@Query("select o from Employee o where o.username like ?1") 		
     List<Employee> query01(String username); //按参数位置赋值 
     @Query("select o from cn.itsource.pss.domain.Employee o where  o.username like :username and o.email like :email") 			 		
     List<Employee> query03(@Param("username") String username,@Param("email")  String email);//按名称赋值

## 4. JpaSpecificationExecutor接口的认识 ##

1）jpa使用paSpecificationExecutor技术完成了Criteria标准(一种比JQPL,HQL更面向对象的语言)，  
2）使用  
Root：查询哪个表（定位到表和字段-> 用于拿到表中的字段）  
\* 可以查询和操作的实体的根  
\* Root 相当于 from Employee  
\* Root 相当于 from Product  
CriteriaQuery：查询哪些字段，排序是什么(主要是把多个查询的条件连系起来)  
CriteriaBuilder：字段之间是什么关系，如何生成一个查询条件，每一个查询条件都是什么方式  
\* 主要判断关系（和这个字段是相等，大于，小于like等）  
Predicate（Expression）：单独每一条查询条件的详细描述 整个 where xxx=xx and yyy=yy …

① 单个条件

List<Employee> emps = employeeRepository.findAll(
                    new Specification<Employee>() {
                        @Override
                        public Predicate toPredicate(Root<Employee> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
                            Path path = root.get("username");//拿到要做查询的字段
                            Predicate p = cb.like(path, "%1%");//like代表做模糊查询，后面就是它的条件值
                            return p;
                        }
                    }
            );
            for (Employee emp : emps) {
                System.out.println(emp);
            } }

②多个条件

public void testFind02() {
        Specification spec = new Specification<Employee>() {
            @Override
            public Predicate toPredicate(Root root, CriteriaQuery query, CriteriaBuilder cb) {
                //加上第一个条件: username like '%1%'
                Path path1 = root.get("username");
                Predicate p1 = cb.like(path1, "%1%");
                //加上第二个条件: email like '%2%'
                Path path2 = root.get("email");
                Predicate p2 = cb.like(path2,"%2%");
                //加上第二个条件: age < 20
                Path path3 = root.get("age");
                Predicate p3 = cb.lt(path3, 20);
               //下面是加上or的条件的方案
               //Predicate p3 = cb.or(p1,p2);
    
                //把两个查询条件放到query对象中去(条件使用where)
                CriteriaQuery where = query.where(p1, p2, p3);//同样可以使用：cb.add(p1,p2,p3)
                //返回查询条件
                return where.getRestriction();
            }
        };
    
        List<Employee> emps = employeeRepository.findAll(spec);
        for (Employee emp : emps) {
            System.out.println(emp);
        }
    }

③ 既分页有排序

Sort sort = new Sort(Sort.Direction.DESC,"age");
    	Pageable page = new  PageRequest(page,size,sort);
    	employeeRepository.findAll(p,page);//p 为Predicate类型值

## 5. jpa-spec插件 ##

1）主要是用于简化JpaSpecificationExecutor  
2) 插件地址:([https://github.com/wenhao/jpa-spec][https_github.com_wenhao_jpa-spec])  
3) Maven导包

<dependency>
        <groupId>com.github.wenhao</groupId>
        <artifactId>jpa-spec</artifactId>
        <version>3.2.3</version>
    </dependency>

1.  使用

>     public void testSpecFind01() {
>      	                Specification<Employee> spec = Specifications.<Employee>and()
>          					.like("username", "%1%")
>         					.build();
>     	                List<Employee> emps = employeeRepository.findAll(spec);
>      }

## 6. query查询条件 ##

1）准备一个对象Query接受前台传来的查询数据，  
2）代码

public void testSpecFindByQuery() {
        //创建模块一个Query对象
        EmployeeQuery baseQuery = new EmployeeQuery();
    //下面的都是测试的条件，可以任何放开进行测试
        //baseQuery.setUsername("1");
        //baseQuery.setAge(20);
        //baseQuery.setEmail("2");
        //baseQuery.setOrderByName("username");
        //baseQuery.setOrderByType("DESC");
        //baseQuery.setCurrentPage(2);
        //baseQuery.setPageSize(5);
    
    	//like(条件boolean值,字段,值)
    	//StringUtils.isNotBlank(baseQuery.getUsername()):判断参数不为空且不为空字符串
        Specification<Employee> spec = Specifications.<Employee>and()
                .like(StringUtils.isNotBlank(baseQuery.getUsername()), "username","%"+baseQuery.getUsername()+"%")
                .like(StringUtils.isNotBlank(baseQuery.getEmail()), "email","%"+baseQuery.getEmail()+"%")
                .lt(baseQuery.getAge()!=null, "age",baseQuery.getAge())
                .build()；
        //这里确定是否需要排序
        Sort sort = null;
        if(baseQuery.getOrderByName()!=null){
            Sort.Direction desc = "DESC".equals(baseQuery.getOrderByType())?Sort.Direction.DESC:Sort.Direction.ASC;
            sort = new Sort(desc,baseQuery.getOrderByName());
        }
        Pageable pageable = new PageRequest(baseQuery.getJpaPage(), baseQuery.getPageSize(),sort);
    
        Page<Employee> page = employeeRepository.findAll(spec, pageable);
        for (Employee emp : page) {
            System.out.println(emp);
        }
    }

## 7.SpringDataJpa扩展 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 5]

1）创建一个BaseRepository接口，继承JpaSpectfifcationExecutor,JpaRepository接口。接口中可以定义自己的方法。  
SimpleJpaRepository类实现了JpaSpectfifcationExecutor,JpaRepository接口，SpringDataJpa自动创建的实现类继承  
SimpleJpaRepository类和EmployeeRepository接口，而BaseRepository中的方法没有实现，所以应该创建一个BaseRepostoryImpl  
来实现BaseRepository接口并继承SimpleJpaRepository

2）代码  
BaseRepository：

@NoRepositoryBean
    public abstract interface BaseRepository<T,ID extends Serializable> 
            extends JpaRepository<T,ID>,JpaSpecificationExecutor<T> {
        //根据Query拿到分页对象(分页)
        Page findPageByQuery(BaseQuery baseQuery);
    
        //根据Query拿到对应的所有数据(不分页)
        List<T> findByQuery(BaseQuery baseQuery);
    
        //根据jpql与对应的参数拿到数据
        List findByJpql(String jpql, Object... values);
    
    }

BaseRepositoryImpl：

public class BaseRepositoryImpl<T,ID extends Serializable> extends SimpleJpaRepository<T,ID> implements BaseRepository<T,ID> {
        private final EntityManager entityManager;
        //必需要实现父类的这个构造器
        public BaseRepositoryImpl(Class<T> domainClass, EntityManager em) {
            super(domainClass, em);
            this.entityManager = em;
        }
        @Override
        public Page findPageByQuery(BaseQuery baseQuery) {
            //第一步：拿到所有高级查询条件
            Specification spec = baseQuery.specification();
            //第二步:拿到排序的值
            Sort sort = baseQuery.sort();
            //第三步:根据条件查询分页数据并且返回
            Pageable pageable = new PageRequest(baseQuery.getNewcurrentPage(), baseQuery.getPageSize(),sort);
            Page<T> page = super.findAll(spec, pageable);
            return page;
        }
        @Override
        public List<T> findByQuery(BaseQuery baseQuery) {
            //第一步：拿到所有高级查询条件
            Specification spec = baseQuery.specification();
            //第二步:拿到排序的值
            Sort sort = baseQuery.sort();
            //第三步:拿到数据返回
            return findAll(spec, sort);
        }
        @Override
        public List findByJpql(String jpql, Object... values) {
            //第一步:创建Query对象
            Query query = entityManager.createQuery(jpql);
            //第二步:把值设置到Query对象中去
            if (values!=null) {
                for (int i = 0; i < values.length; i++) {
                    query.setParameter(i + 1, values[i]);
                }
            }
            //第三步：返回数据
            return query.getResultList();
        }
    }

同时还要告诉SpringDataJpa在创建对象是不使用SimpleJpaRepository，而使用自己写的BaseRepositoryImpl  
① 先创建一个BaseRepositoryFactoryBean类

public class BaseRepositoryFactoryBean<T extends Repository<S, ID>, S, ID extends Serializable> extends JpaRepositoryFactoryBean<T,S,ID> {
        @Override
        protected RepositoryFactorySupport createRepositoryFactory(EntityManager entityManager) {
            return new MyRepositoryFactory<T,ID>(entityManager); //注：这里创建是我们的自定义类
        }
    
        //继承JpaRepositoryFactory后，把返回的对象修改成我们自己的实现
        private static  class MyRepositoryFactory<T,ID extends Serializable>   extends JpaRepositoryFactory {
            private final EntityManager entityManager;
            /**
             * Creates a new {@link JpaRepositoryFactory}.
             *
             * @param entityManager must not be {@literal null}
             */
            public MyRepositoryFactory(EntityManager entityManager) {
                super(entityManager);
                this.entityManager = entityManager;
            }
            //这里返回最后的功能对象
            @Override
            protected Object getTargetRepository(RepositoryInformation information) {
                return new BaseRepositoryImpl<T,ID>((Class<T>)information.getDomainType(),entityManager);
            }
            //确定功能对象的类型
            @Override
            protected Class<?> getRepositoryBaseClass(RepositoryMetadata metadata) {
                return BaseRepositoryImpl.class;
            }
        }
    }

② 在applicationContext.xml中配置  
![在这里插入图片描述][20190331011230586.png]  
③ EmployeeRepository继承BaseRepositoryImpl

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/2019033021142440.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 4]: /images/20220225/4673a2caf6da47ca8c00841307dbd68f.png
[https_github.com_wenhao_jpa-spec]: https://github.com/wenhao/jpa-spec
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0p1bmVfRmx5aW5nRnJvc3Q_size_16_color_FFFFFF_t_70 5]: /images/20220225/9900448296a94fbd8d4e0b2b848b61cb.png
[20190331011230586.png]: /images/20220225/90adebe98c2b42daa17b951bef8bb321.png