整合Mybatis

1. 导入相关jar包
   • junit
   • Mybatis
   • Mysql数据库
   • Spring
   • Aop织入
   • Mybatis-Spring [new]
2. 编写配置文件
3. 测试

环境搭建

• 新建Maven模块spring-10-mybatis

• 导包

  <dependency>

  <groupId>mysql</groupId>

  <artifactId>mysql-connector-java</artifactId>

  <version>5.1.46</version>

  </dependency>

  <dependency>

  <groupId>org.mybatis</groupId>

  <artifactId>mybatis</artifactId>

  <version>3.5.2</version>

  </dependency>

  <dependency>

  <groupId>org.springframework</groupId>

  <artifactId>spring-webmvc</artifactId>

  <version>5.2.0.RELEASE</version>

  </dependency>

  <dependency>

  <groupId>org.springframework</groupId>

  <artifactId>spring-jdbc</artifactId>

  <version>5.1.9.RELEASE</version>

  </dependency>

  <dependency>

  <groupId>org.mybatis</groupId>

  <artifactId>mybatis-spring</artifactId>

  <version>2.0.2</version>

  </dependency>

回忆Mybatis

1. 编写实体类

2. 编写核心配置文件

   <?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>

   <environments default="development">

   <environment id="development">

   <transactionManager type="JDBC"/>

   <dataSource type="POOLED">

   <property name="driver" value="com.mysql.jdbc.Driver"/>

   <property name="url" value="jdbc:mysql://localhost:3306/test?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>

   <property name="username" value="root"/>

   <property name="password" value="root"/>

   </dataSource>

   </environment>

   </environments>

   <mappers>

   <mapper resource="com/bsx/mapper/UserMapper.xml"/>

   </mappers>

   </configuration>

3. 编写接口

   public interface UserMapper {

   public List<User> queryUser();

   }

4. 编写Mapper.xml

   <?xml version="1.0" encoding="UTF-8" ?>

   <!DOCTYPE mapper

   PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

   "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

   <mapper namespace="com.bsx.mapper.UserMapper">

   <select id="queryUser" resultType="com.bsx.pojo.User">

   SELECT * FROM USER;

   </select>

   </mapper>

5. 解决找不到Mapper.xml文件的问题 在pom.xml中添加

   <build>

   <resources>

   <resource>

   <directory>src/main/resources</directory>

   <includes>

   <include>**/*.properties</include>

   <include>**/*.xml</include>

   </includes>

   <filtering>true</filtering>

   </resource>

   <resource>

   <directory>src/main/java</directory>

   <includes>

   <include>**/*.properties</include>

   <include>**/*.xml</include>

   </includes>

   <filtering>true</filtering>

   </resource>

   </resources>

   </build>

6. 测试

   @Test

   public void testMybatis() throws IOException {

   InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");

   SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

   SqlSession sqlSession = sqlSessionFactory.openSession();

   try {

   UserMapper mapper = sqlSession.getMapper(UserMapper.class);

   List<User> users = mapper.queryUser();

   for (User user : users) {

   System.out.println(user);

   }

   } catch (Exception e) {

   e.printStackTrace();

   } finally {

   sqlSession.close();

   }

   }

1. Spring整合Mybatis

1.1 Mybatis-Spring

什么是Mybatis-Spring

帮助将Mybatis代码无缝的整合到Spring中。它允许Mybatis参与到Spring的事务管理中，创建映射其Mapper和sqlSession并注入到bean中，以及将Mybatis的异常转换为Spring的DataAccessException。最终可以做到代码不依赖于Mybatis、Spring或Mybatis-Spring

1.1.1 导包

在环境搭建部分导过了

1.1.2 整合方式一 [重要]

• Spring容器 -> 新建spring-dao.xml 注册以下东西

  • sqlSessionFactory （可以实现一切mybatis核心配置文件的功能）
    • 指定数据源DataSource
    • 绑定Mybatis配置文件
    • 绑定mapper.xml文件
  • DataSource
    • 使用Spring数据源替换Mybatis的配置 （还可用c3p0 druid） DriverManagerDataSource类
    • 删除Mybatis核心配置文件中关于连接数据库的配置
  • SqlSessionTemplate (代替SqlSession)
    • 构造器注入，要求传入一个sqlSessionFactory
  <beans xmlns="http://www.springframework.org/schema/beans"

  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  xmlns:aop="http://www.springframework.org/schema/aop"

  xsi:schemaLocation="http://www.springframework.org/schema/beans

  https://www.springframework.org/schema/beans/spring-beans.xsd

  http://www.springframework.org/schema/aop

  https://www.springframework.org/schema/aop/spring-aop.xsd">

  <!-- DataSource 来自导入的包spring jdbc -->

  <bean id="datasource"

  class="org.springframework.jdbc.datasource.DriverManagerDataSource">

  <property name="driverClassName" value="com.mysql.jdbc.Driver"/>

  <property name="url" value="jdbc:mysql://localhost:3306/test?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>

  <property name="username" value="root"/>

  <property name="password" value="root"/>

  </bean>

  <!--sqlSessionFactory-->

  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

  <property name="dataSource" ref="datasource"/>

  <property name="configLocation" value="classpath:mybatis-config.xml"/>

  <property name="mapperLocations" value="classpath:com/bsx/mapper/*.xml"/>

  </bean>

  </beans>

• Mapper实现类MapperImpl 所有操作使用sqlSessionTemplate来执行

  public class UserMapperImpl implements UserMapper{

  private SqlSessionTemplate sqlSession;

  //用来让Spring注入

  public void setSqlSession(SqlSessionTemplate sqlSession) {

  this.sqlSession = sqlSession;

  }

  public List<User> queryUser() {

  UserMapper mapper = sqlSession.getMapper(UserMapper.class);

  List<User> users = mapper.queryUser();

  return users;

  }

  }

  把实现类注册到Spring容器

  <!-- DataSource 来自导入的包spring jdbc -->

  <bean id="datasource"

  class="org.springframework.jdbc.datasource.DriverManagerDataSource">

  <property name="driverClassName" value="com.mysql.jdbc.Driver"/>

  <property name="url" value="jdbc:mysql://localhost:3306/test?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>

  <property name="username" value="root"/>

  <property name="password" value="root"/>

  </bean>

  <!--sqlSessionFactory-->

  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

  <property name="dataSource" ref="datasource"/>

  <property name="configLocation" value="classpath:mybatis-config.xml"/>

  <property name="mapperLocations" value="classpath:com/bsx/mapper/*.xml"/>

  </bean>

  <!-- sqlSessionTemplate 构造器注入一个sqlSessionFactory-->

  <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">

  <constructor-arg index="0" ref="sqlSessionFactory"/>

  </bean>

  <!-- userMapperImpl-->

  <bean id="userMapper" class="com.bsx.mapper.UserMapperImpl">

  <property name="sqlSession" ref="sqlSession"/>

  </bean>
  • 新建一个applicationContext.xml引入上面的spring-dao.xml
    <beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xmlns:aop="http://www.springframework.org/schema/aop"

    xsi:schemaLocation="http://www.springframework.org/schema/beans

    https://www.springframework.org/schema/beans/spring-beans.xsd

    http://www.springframework.org/schema/aop

    https://www.springframework.org/schema/aop/spring-aop.xsd">

    <import resource="spring-dao.xml"/>

    </beans>

• 测试

  @Test

  public void testSpringMybatis(){

  ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

  UserMapper userMapper = context.getBean("userMapper", UserMapper.class);

  List<User> users = userMapper.queryUser();

  for (User user : users) {

  System.out.println(user);

  }

  }

步骤

1. 编写数据源配置
2. 用sqlSessionFactoryBean 创建 sqlSessionFactory
3. 创建sqlSessionTemplate
4. 需要给mapper接口加实现类 [新]
5. 将编写的实现类注册到Spring容器，提供set方法让spring注入
6. 编写测试，直接从Spring容器拿Mapper实现类对象，调用方法

1.1.3 整合方式二

这种方式继承sqlSessionDaoSupport类，然后直接使用它的getSqlSession方法获得sqlSessionFactoryTemplate对象，这种方式不需要在Spring中注册一个sqlSessionFactoryTemplate

这种方式要求在将实现类注册到Spring容器时传入一个sqlSessionFactory对象，因为sqlSessionDaoSupport需要它来实例化sqlSessionTemplate

• mapper实现类

  public class UserMapperImpl2 extends SqlSessionDaoSupport implements UserMapper {

  public List<User> queryUser() {

  return getSqlSession().getMapper(UserMapper.class).queryUser();

  }

  }

• 注册到Spring

  <bean id="userMapper2" class="com.bsx.mapper.UserMapperImpl2">

  <property name="sqlSessionFactory" ref="sqlSessionFactory"/>

  </bean>

• 测试

  @Test

  public void testSpringMybatis(){

  ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");

  UserMapper userMapper = context.getBean("userMapper2", UserMapper.class);

  List<User> users = userMapper.queryUser();

  for (User user : users) {

  System.out.println(user);

  }

  }