Spring 从入门到精通系列 07 —— 基于XML与注解方式的IOC案例编写

刺骨的言语ヽ痛彻心扉 2023-10-11 15:46 42阅读 0赞

本文使用 XML 方式和注解方式实现单表的 CRUD操作，连带巩固 IOC 配置过程。

![在这里插入图片描述][20210531194346342.png_pic_center]

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#### 文章目录 ####

*   *  一、基于 XML 的 IOC 的案例
     *   *  1.1 导入依赖
         *  1.2 账户实体类
         *  1.3 业务层接口及实现类
         *  1.4 持久层接口及实现类
         *  1.5 bean.xml ★
         *  1.6 测试方法
     *  二、基于注解配置的 IOC 案例
     *   *  2.1 业务层接口实现类
         *  2.2 持久层接口实现类
         *  2.3 bean.xml ★

--------------------

### 一、基于 XML 的 IOC 的案例 ###

**工程目录：**  
![在这里插入图片描述][20210601223328851.png_pic_left]

--------------------

#### 1.1 导入依赖 ####

<dependencies>
    	<dependency>
    	    <groupId>org.springframework</groupId>
    	    <artifactId>spring-context</artifactId>
    	    <version>5.0.2.RELEASE</version>
    	</dependency>
    	<dependency>
    	    <groupId>commons-dbutils</groupId>
    	    <artifactId>commons-dbutils</artifactId>
    	    <version>1.4</version>
    	</dependency>
    	<dependency>
    	    <groupId>org.springframework</groupId>
    	    <artifactId>spring-test</artifactId>
    	    <version>5.0.2.RELEASE</version>
    	</dependency>
    	<dependency>
    	    <groupId>mysql</groupId>
    	    <artifactId>mysql-connector-java</artifactId>
    	    <version>5.1.6</version>
    	</dependency>
    	<dependency>
    	    <groupId>c3p0</groupId>
    	    <artifactId>c3p0</artifactId>
    	    <version>0.9.1.2</version>
    	</dependency>
    	<dependency>
    	    <groupId>junit</groupId>
    	    <artifactId>junit</artifactId>
    	    <version>4.12</version>
    	</dependency>
    </dependencies>

--------------------

#### 1.2 账户实体类 ####

/**
     * 账户的实体类
     */
    public class Account implements Serializable {
        
        private Integer id;
        private String name;
        private Float money;
    
        public Integer getId() {
        
            return id;
        }
    
        public void setId(Integer id) {
        
            this.id = id;
        }
    
        public String getName() {
        
            return name;
        }
    
        public void setName(String name) {
        
            this.name = name;
        }
    
        public Float getMoney() {
        
            return money;
        }
    
        public void setMoney(Float money) {
        
            this.money = money;
        }
    
        @Override
        public String toString() {
        
            return "Account{" +
                    "id=" + id +
                    ", name='" + name + '\'' +
                    ", money=" + money +
                    '}';
        }
    }

--------------------

#### 1.3 业务层接口及实现类 ####

/**
     * 账户的业务层接口
     */
    public interface IAccountService {
        
    
        /**
         * 查询所有
         * @return
         */
        List<Account> findAllAccount();
    
        /**
         * 查询一个
         * @return
         */
        Account findAccountById(Integer id);
    
        /**
         * 添加账户
         * @param account
         */
        void insertAccount(Account account);
    
        /**
         * 更新账户
         * @param account
         */
        void updateAccount(Account account);
    
        /**
         * 删除
         * @param id
         */
        void deleteAccount(Integer id);
    }

/**
     * 账户的业务层实现类
     */
    public class AccountServiceImpl implements IAccountService {
        
    
        private IAccountDao accountDao;
    
        public void setAccountDao(IAccountDao accountDao) {
        
            this.accountDao = accountDao;
        }
    
        public List<Account> findAllAccount() {
        
            return accountDao.findAllAccount();
        }
    
        public Account findAccountById(Integer id) {
        
            return accountDao.findAccountById(id);
        }
    
        public void insertAccount(Account account) {
        
            accountDao.insertAccount(account);
        }
    
        public void updateAccount(Account account) {
        
            accountDao.updateAccount(account);
        }
    
        public void deleteAccount(Integer id) {
        
            accountDao.deleteAccount(id);
        }
    }

--------------------

#### 1.4 持久层接口及实现类 ####

/**
     * 账户的持久层接口
     */
    public interface IAccountDao {
        
    
        /**
         * 查询所有
         * @return
         */
        List<Account> findAllAccount();
    
        /**
         * 查询一个
         * @return
         */
        Account findAccountById(Integer id);
    
        /**
         * 添加账户
         * @param account
         */
        void insertAccount(Account account);
    
        /**
         * 更新账户
         * @param account
         */
        void updateAccount(Account account);
    
        /**
         * 删除
         * @param id
         */
        void deleteAccount(Integer id);
    }

/**
     * 账户的持久层实现类
     */
    public class AccountDaoImpl implements IAccountDao {
        
    
        private QueryRunner runner;
    
        public void setRunner(QueryRunner runner) {
        
            this.runner = runner;
        }
    
        public List<Account> findAllAccount() {
        
            try {
        
                return runner.query("select * from account", new BeanListHandler<Account>(Account.class));
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public Account findAccountById(Integer id) {
        
            try {
        
                return runner.query("select * from account where id = ?", new BeanHandler<Account>(Account.class), id);
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public void insertAccount(Account account) {
        
            try {
        
                runner.update("insert into account(name, money) values(?,?)", account.getName(), account.getMoney());
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public void updateAccount(Account account) {
        
            try {
        
                runner.update("update account set name = ?, money = ? where id = ?", account.getName(), account.getMoney(), account.getId());
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public void deleteAccount(Integer id) {
        
            try {
        
                runner.update("delete from account where id = ?", id);
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    }

> **注意：** 这里使用 dbutils 工具类的 QueryRunner 对象与数据库进行交互，也将对象的创建也交给 Spring，因此生成 get、set 方法。

--------------------

#### 1.5 bean.xml ★ ####

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans.xsd">
    
        
        <bean id="accountService" class="com.itheima.service.impl.AccountServiceImpl">
            
            <property name="accountDao" ref="accountDao"></property>
        </bean>
    
        
        <bean id="accountDao" class="com.itheima.dao.impl.AccountDaoImpl">
            
            <property name="runner" ref="runner"></property>
        </bean>
    
        
        <bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype">
            
            <constructor-arg name="ds" ref="dataSource"></constructor-arg>
        </bean>
    
        
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
            
            <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
            <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/springdb"></property>
            <property name="user" value="root"></property>
            <property name="password" value="000000"></property>
        </bean>
    
    </beans>

> **注意：**  
>  1. 在配置对象间的依赖关系，首先配置 service 业务层对象，因为业务层对象中含有 dao 对象，所以就需要依赖注入的方式注入 dao 对象，这时候还没有 dao 对象所以还需要配置 dao 对象 … 以此类推。  
>  2. QueryRunner 的数据源是通过调用带参构造函数构造的。  
>  3. QueryRunner 默认是单例对象，为了防止线程干扰，可以使用 scope=“prototype” 让其变为多例对象。

--------------------

#### 1.6 测试方法 ####

public class AccountServiceTest {
        
    
        private ApplicationContext ac;
        private IAccountService as;
    
        @Before
        public void init(){
        
            ac = new ClassPathXmlApplicationContext("bean.xml");
            as = (IAccountService) ac.getBean("accountService");
        }
    
    
        @Test
        public void testFindAll(){
        
            List<Account> accounts = as.findAllAccount();
            for(Account account:accounts){
        
                System.out.println(account);
            }
        }
    
        @Test
        public void testFindOne(){
        
            Account account = as.findAccountById(2);
            System.out.println(account);
        }
        @Test
        public void testInsert(){
        
            Account account = new Account();
            account.setName("test");
            account.setMoney(5000f);
            as.insertAccount(account);
        }
        @Test
        public void testUpdate(){
        
            Account account = as.findAccountById(4);
            account.setName("test");
            account.setMoney(6000f);
            as.updateAccount(account);
        }
        @Test
        public void testDelete(){
        
            as.deleteAccount(4);
        }
    }

--------------------

### 二、基于注解配置的 IOC 案例 ###

**工程目录：**  
![在这里插入图片描述][20210601232305237.png_pic_left]  
除了以下内容与 xml 案例中的不同，其余部分都相同。

--------------------

#### 2.1 业务层接口实现类 ####

/**
     * 账户的业务层实现类
     */
    @Service("accountService")
    public class AccountServiceImpl implements IAccountService {
        
    
        @Autowired
        private IAccountDao accountDao;
    
        public List<Account> findAllAccount() {
        
            return accountDao.findAllAccount();
        }
    
        public Account findAccountById(Integer id) {
        
            return accountDao.findAccountById(id);
        }
    
        public void insertAccount(Account account) {
        
            accountDao.insertAccount(account);
        }
    
        public void updateAccount(Account account) {
        
            accountDao.updateAccount(account);
        }
    
        public void deleteAccount(Integer id) {
        
            accountDao.deleteAccount(id);
        }
    }

**注意：**

1.  当使用 Autowired 自动按照类型注入时，set 方法也就不是必须的了。
2.  @Component、@Controller、@Service、@Repository 四个注解的作用是相同的，但是为清晰，还是按照标准来。

--------------------

#### 2.2 持久层接口实现类 ####

/**
     * 账户的持久层实现类
     */
    @Repository("accountDao")
    public class AccountDaoImpl implements IAccountDao {
        
    
        @Autowired
        private QueryRunner runner;
    
        public List<Account> findAllAccount() {
        
            try {
        
                return runner.query("select * from account", new BeanListHandler<Account>(Account.class));
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public Account findAccountById(Integer id) {
        
            try {
        
                return runner.query("select * from account where id = ?", new BeanHandler<Account>(Account.class), id);
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public void insertAccount(Account account) {
        
            try {
        
                runner.update("insert into account(name, money) values(?,?)", account.getName(), account.getMoney());
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public void updateAccount(Account account) {
        
            try {
        
                runner.update("update account set name = ?, money = ? where id = ?", account.getName(), account.getMoney(), account.getId());
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    
        public void deleteAccount(Integer id) {
        
            try {
        
                runner.update("delete from account where id = ?", id);
            } catch (SQLException e) {
        
                throw new RuntimeException(e);
            }
        }
    }

--------------------

#### 2.3 bean.xml ★ ####

当使用注解形式开发时需使用如下配置来告知spring在创建容器时，需要扫描的包。

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

<?xml version="1.0" encoding="UTF-8"?>
    <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">
    
    	
        <context:component-scan base-package="com.itheima"></context:component-scan>
    
        
        <bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype">
            
            <constructor-arg  name="ds" ref="dataSource"></constructor-arg>
        </bean>
    
        
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
            
            <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
            <property name="jdbcUrl" value="jdbc:mysql://localhost:3306/springdb"></property>
            <property name="user" value="root"></property>
            <property name="password" value="000000"></property>
        </bean>
    
    </beans>

**注意：** 由于 QueryRunner 是 dbutils 下的一个类，因此无法在 QueryRunner 类上加入注解，所以 QueryRunner 目前只能在 bean.xml 中配置。在下一篇文章中，会介绍如何用纯注解的方式编写 IOC。

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本文使用 XML 方式和注解方式实现单表的 CRUD操作，如果大家对文章内容还存在一些疑问，欢迎大家在评论区留言哦~

[20210531194346342.png_pic_center]: https://img-blog.csdnimg.cn/20210531194346342.png#pic_center
[20210601223328851.png_pic_left]: https://img-blog.csdnimg.cn/20210601223328851.png#pic_left
[20210601232305237.png_pic_left]: https://img-blog.csdnimg.cn/20210601232305237.png#pic_left