Spring和MyBatis整合

MyBatis-Spring官方文档

MyBatis-Spring 会帮助你将 MyBatis 代码无缝地整合到 Spring 中。它将允许 MyBatis 参与到 Spring 的事务管理之中，创建映射器 mapper 和 SqlSession 并注入到 bean 中，以及将 Mybatis 的异常转换为 Spring 的 DataAccessException。 最终，可以做到应用代码不依赖于 MyBatis，Spring 或 MyBatis-Spring。

1. 所需依赖

  • Junit
  • MyBatis
  • MySQL
  • Spring-core
  • Spring-context
  • Spring-beans
  • Spring-aop
  • aspectjweaver
  • MyBatis-Spring【new】
  • Spring-JDBC【new】
<dependencies>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.3.9</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.3.9</version>
  </dependency>
  <!-- https://mvnrep
        ository.com/artifact/org.springframework/spring-beans -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>5.3.9</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>5.3.9</version>
  </dependency>
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.13.2</version>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.9.8.M1</version>
  </dependency>
  <dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.5.7</version>
  </dependency>
  <dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>2.0.6</version>
  </dependency>
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.25</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>5.2.16.RELEASE</version>
  </dependency>
</dependencies>

2. 配置MyBatis环境

参考

3. 整合MyBatis

3.1. 方式一

此方式主要是将MyBatis中的配置迁移到Spring配置文件中，需要配置Mapper，同时需要多一个Mapper接口的实现类。

本案例在上述环境中做出更改

  1. 配置Spring的xml配置文件

    将数据源导入到Spring中（相当于把db.properties导入）

    在配置文件中配置SqlSessionFactory

    配置SqlSession

    <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--configuration核心配置文件-->
<configuration>
    <typeAliases>
        <typeAlias type="org.gs.pojo.User" alias="user"/>
    </typeAliases>
    <mappers>
        <mapper resource="org/gs/mapper/UserMapper.xml" />
    </mappers>
</configuration>

    <?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <!--从db.properties获取db配置信息-->
    <context:property-placeholder location="db.properties"/>
    <!--将db配置信息配置到spring的数据源中-->
    <!-- 这里也可以选择其他数据源，如 c3p0 dbcp druid-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
    </bean>

    <!--配置SqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!--将数据源内容注入-->
        <property name="dataSource" ref="dataSource"/>
        <!--可以携带mybatis原有的配置文件，一般用来指定别名-->
        <property name="configLocation" value="classpath:mybatis-config.xml" />
        <!--此处也可以映射文件-->
        <!--其实mybatis配置文件中的配置都可以在这里完成-->
        <property name="mapperLocations" value="classpath:org/gs/mapper/UserMapper.xml"/>
    </bean>

    <!--配置SqlSession-->
    <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
        <!--将SqlSessionFactory通过构造器注入，实际上也只有这一种注入方法-->
        <constructor-arg index="0" ref="sqlSessionFactory"/>
    </bean>

      <!--这里需要多一个实现类，Spring需要进行依赖注入-->
    <!--配置mapper实现类，注入SqlSession-->
    <bean id="userMapper" class="org.gs.mapper.UserMapperImpl">
        <property name="sqlSessionTemplate" ref="sqlSessionTemplate"/>
    </bean>
</beans>

  2. UserMapper接口实现类

    package org.gs.mapper;

import org.gs.pojo.User;
import org.mybatis.spring.SqlSessionTemplate;

import java.util.List;

/**
 * @author admin
 * @date 2021/9/13 7:23 下午
 */
public class UserMapperImpl implements UserMapper{
    // Spring管理的MyBatis需要注入，需要有一个具体实现
    private SqlSessionTemplate sqlSessionTemplate;

    // 默认setter注入
    public void setSqlSessionTemplate(SqlSessionTemplate sqlSessionTemplate) {
        this.sqlSessionTemplate = sqlSessionTemplate;
    }

    @Override
    public List<User> getUsers() {
        UserMapper mapper = sqlSessionTemplate.getMapper(UserMapper.class);
        return mapper.getUsers();
    }
}

  3. 测试方法

    @Test
public void test() {
  ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
  UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
  userMapper.getUsers().forEach(System.out::println);
}

3.2. 方式二

接口实现类继承SqlSessionDaoSupport类，可以不用在xml配置文件中配置SqlSessionTemplate

  1. 配置文件

    <?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--configuration核心配置文件-->
<configuration>
    <typeAliases>
        <typeAlias type="org.gs.pojo.User" alias="user"/>
    </typeAliases>
    <mappers>
        <mapper resource="org/gs/mapper/UserMapper.xml" />
    </mappers>
</configuration>

    <?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="db.properties"/>
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml" />
    </bean>

    <!--配置mapper实现类，注入SqlSessionFactory-->
    <bean id="userMapper" class="org.gs.mapper.UserMapperImpl">
        <property name="sqlSessionFactory" ref="sqlSessionFactory"/>
    </bean>
</beans>

  2. 实现类，继承SqlSessionDaoSupport类

    package org.gs.mapper;

import org.gs.pojo.User;
import org.mybatis.spring.support.SqlSessionDaoSupport;

import java.util.List;

/**
 * @author admin
 * @date 2021/9/13 7:23 下午
 */
public class UserMapperImpl extends SqlSessionDaoSupport implements UserMapper{

    @Override
    public List<User> getUsers() {
        return getSqlSession().getMapper(UserMapper.class).getUsers();
    }
}

  3. 测试类

    import org.gs.mapper.UserMapper;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author admin
 * @date 2021/9/13 6:10 下午
 */
public class UserDaoTest {
    @Test
    public void test() {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        UserMapper userMapper = context.getBean("userMapper", UserMapper.class);
        userMapper.getUsers().forEach(System.out::println);
    }
}

3.3. 方式三

动态实现Dao接口，无需编写Dao接口实现类

  1. 配置文件

    <?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
        https://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        https://www.springframework.org/schema/context/spring-context.xsd">

    <context:property-placeholder location="db.properties"/>
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml" />
    </bean>

      <!--配置mapper接口扫描包，动态的实现mapper接口可以注入到Spring容器中-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
          <!--注入SqlSessionFactory-->
      <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
      <!--要扫描的dao包-->
      <property name="basePackage" value="org.gs.mapper" />
      </bean>
</beans>
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