第九讲 整合MyBatis

一、步骤

1. 导入相关jar包

           <dependency>

                <groupId>org.springframework</groupId>

                <artifactId>spring-webmvc</artifactId>

                <version>4.2.1.RELEASE</version>

           </dependency>

           <dependency>

                <groupId>org.aspectj</groupId>

                <artifactId>aspectjweaver</artifactId>

                <version>1.8.10</version>

           </dependency>

           <dependency>

                <groupId>mysql</groupId>

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

                <version>5.1.38</version>

           </dependency>

           <dependency>

                <groupId>org.mybatis</groupId>

                <artifactId>mybatis</artifactId>

                <version>3.4.1</version>

           </dependency>

           <dependency>

                <groupId>org.mybatis</groupId>

                <artifactId>mybatis-spring</artifactId>

                <version>1.3.1</version>

           </dependency>

           <dependency>

                <groupId>org.springframework</groupId>

                <artifactId>spring-jdbc</artifactId>

                <version>4.2.1.RELEASE</version>

           </dependency>

切记：spring系列的包，一定要版本相符。不然会出现类找不到的问题（即使这个类在spring的包中能找到）。就比如这里之前    spring-jdbc的版本是4.3.7.RELEASE，但是spring-webmvc的版本是4.2.1.RELEASE要低于spring-jdbc的版本。所以测试结果会    出现找不到类的情况。

只要是出现 java.lang.NoSuchMethodError，          java.lang.ClassNotFoundException，          Cannot find class ，    这些类型的异常，都可以更换jar包的版本来看看。

2. 编写配置文件

          spring的配置文件（beans.xml）：

<?xmlversion="1.0"encoding="UTF-8"?>

<beansxmlns="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">

     

     <!-- 配置数据源 -->

     <beanid="dataSource"class="org.springframework.jdbc.datasource.DriverManagerDataSource">

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

           <propertyname="url"value="jdbc:mysql://localhost:3306/test"></property>

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

           <propertyname="password"value="123456"></property>

     </bean>

     

     <!-- 配置sqlSessionFactory -->

     <beanid="sqlSessionFactory"class="org.mybatis.spring.SqlSessionFactoryBean">

           <propertyname="dataSource"ref="dataSource"></property>

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

     </bean>

     

     <beanid="sqlSessionTemplate"class="org.mybatis.spring.SqlSessionTemplate">

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

     </bean>

     

     <beanid="userDao"class="com.liujie.dao.impl.UserDaoImpl">

           <propertyname="sqlSession"ref="sqlSessionTemplate"></property>

     </bean>

     

</beans>

          mybatis的配置文件（mybatis-config.xml）：

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEconfiguration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

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

<configuration>

     <typeAliases>

           <packagename="com.liujie.model"/>

     </typeAliases>

     

     <mappers>

           <mapperresource="com/liujie/model/user.mapper.xml"/>

     </mappers>

</configuration>

          user.mapper.xml：

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEmapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

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

<mappernamespace="com.liujie.model.UserMapper">

     <selectid="selectUser"resultType="User">

           select * from user

     </select>

     

     <selectid="selectUserById"resultType="User">

           select * from user where id = #{id}

     </select>

</mapper>

3. 实现

          Dao的实现：

publicclass UserDaoImpl implementsUserDao {

     privateSqlSessionTemplatesqlSession;

     

     publicvoid setSqlSession(SqlSessionTemplatesqlSession) {

           this.sqlSession= sqlSession;

     }

     publicList<User> selectUser() {

           returnsqlSession.selectList("com.liujie.model.UserMapper.selectUser");

     }

     publicUser selectUserById(intid) {

           returnsqlSession.selectOne("com.liujie.model.UserMapper.selectUserById",id);

     }

}

          测试：

publicclass Test {

     publicstatic void main(String[]args) {

           ApplicationContextcontext = newClassPathXmlApplicationContext("beans.xml");

           

           UserDaouserDao = (UserDao)context.getBean("userDao");

           System.out.println(userDao.selectUser().size());

     }

}

二、声明式事务管理

1. 使用声明式事务之前

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEmapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

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

<mappernamespace="com.liujie.model.UserMapper">

     <selectid="selectUser"resultType="User">

           select * from user

     </select>

     

     <selectid="selectUserById"resultType="User">

           select * from user where id = #{id}

     </select>

     <insertid="addUser"parameterType="User"useGeneratedKeys="true">

           insert into user(name, pwd) values(#{name}, #{pwd})

     </insert>

     

     <deleteid="remove">

           <!-- 这里故意写错，执行时就会报错 -->

           deletes from user where id = #{id}

     </delete>

     

</mapper>

publicclass UserDaoImpl implementsUserDao {

     privateSqlSessionTemplate sqlSession;

     

     publicvoid setSqlSession(SqlSessionTemplate sqlSession) {

           this.sqlSession= sqlSession;

     }

     publicList<User> selectUser() {

           Useruser = newUser();

           user.setName("大虾");

           user.setPwd("666");

          sqlSession.insert("com.liujie.model.UserMapper.addUser",user);

           //执行delete时会报错

          sqlSession.delete("com.liujie.model.UserMapper.remove", 20);

           returnsqlSession.selectList("com.liujie.model.UserMapper.selectUser");

     }

     publicUser selectUserById(intid) {

           returnsqlSession.selectOne("com.liujie.model.UserMapper.selectUserById",id);

     }

}

运行结果：虽然在执行delete的时候报错了，但是insert还是执行成功了。

2. 使用声明式事务以后

<?xmlversion="1.0"encoding="UTF-8"?>

<beansxmlns="http://www.springframework.org/schema/beans"

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

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

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

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

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

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

     http://www.springframework.org/schema/tx/spring-tx.xsd

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

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

     

     <!-- 配置数据源 -->

     <beanid="dataSource"class="org.springframework.jdbc.datasource.DriverManagerDataSource">

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

           <propertyname="url"value="jdbc:mysql://localhost:3306/test"></property>

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

           <propertyname="password"value="123456"></property>

     </bean>

     

     <!-- 声明式事务配置 -->

     <!-- 配置事务管理器 -->

     <beanid="txManager"

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

           <propertyname="dataSource"ref="dataSource"/>

     </bean>

     <!-- 配置事务通知 -->

     <tx:adviceid="txAdvice"transaction-manager="txManager">

           <tx:attributes>

                <!-- 配置哪些方法使用什么样的事务，配置事务的传播特性 -->

                <tx:methodname="add"propagation="REQUIRED"/>

                <tx:methodname="insert"propagation="REQUIRED"/>

                <tx:methodname="update"propagation="REQUIRED"/>

                <tx:methodname="delete"propagation="REQUIRED"/>

                <tx:methodname="remove*"propagation="REQUIRED"/>

                <tx:methodname="get"read-only="true"/>

                <tx:methodname="*"propagation="REQUIRED"/>

           </tx:attributes>

     </tx:advice>

     <aop:config>

           <!-- 切入点应该是service.impl下的所有类的所有方法，这里为了方便测试所以直接用了dao.impl -->

           <aop:pointcutexpression="execution(* com.liujie.dao.impl.*.*(..))"id="pointcut"/>

           <aop:advisoradvice-ref="txAdvice"pointcut-ref="pointcut"/>

     </aop:config>

     <!-- 声明式事务配置结束 -->

     

     <!-- 配置sqlSessionFactory -->

     <beanid="sqlSessionFactory"class="org.mybatis.spring.SqlSessionFactoryBean">

           <propertyname="dataSource"ref="dataSource"></property>

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

     </bean>

     

     <beanid="sqlSessionTemplate"class="org.mybatis.spring.SqlSessionTemplate">

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

     </bean>

     

     <beanid="userDao"class="com.liujie.dao.impl.UserDaoImpl">

           <propertyname="sqlSession"ref="sqlSessionTemplate"></property>

     </bean>

     

</beans>

Spring事务类型详解：    PROPAGATION_REQUIRED--支持当前事务，如果当前没有事务，就新建一个事务。这是最常见的选择。    PROPAGATION_SUPPORTS--支持当前事务，如果当前没有事务，就以非事务方式执行。    PROPAGATION_MANDATORY--支持当前事务，如果当前没有事务，就抛出异常。    PROPAGATION_REQUIRES_NEW--新建事务，如果当前存在事务，把当前事务挂起。    PROPAGATION_NOT_SUPPORTED--以非事务方式执行操作，如果当前存在事务，就把当前事务挂起。    PROPAGATION_NEVER--以非事务方式执行，如果当前存在事务，则抛出异常。    PROPAGATION_NESTED--如果当前存在事务，则在嵌套事务内执行。如果当前没有事务，则进行与PROPAGATION_REQUIRED类似的    操作。

<tx:methodname="get"read-only="true"/>就是说名为get的函数里面只能有select等读取操作，不能有insert等写入操作。否则就     会报异常。

运行结果：publicList<User> selectUser()里面的所有对数据库的操作都不会成功。（一旦其中一个出错，其他的都会回滚）

三、使用最新的mybatis-spring（这里用的是1.3.1）整合。在spring配置文件中，不需要管理sqlSessionTemplate。在Dao的实现中，需要

     继承SqlSessionDaoSupport。

现在的写法：（第二中方式）      <!-- 配置sqlSessionFactory -->      <beanid="sqlSessionFactory"class="org.mybatis.spring.SqlSessionFactoryBean">            <propertyname="dataSource"ref="dataSource"></property>            <propertyname="configLocation"value="classpath:mybatis-config.xml"></property>      </bean>      <beanid="userDao"class="com.liujie.dao.impl.UserDaoImpl">            <propertyname="sqlSessionFactory"ref="sqlSessionFactory"></property>      </bean> publicclass UserDaoImpl extendsSqlSessionDaoSupportimplementsUserDao {      publicList<User> selectUser() {            returngetSqlSession().selectList("com.liujie.model.UserMapper.selectUser");      }      publicUser selectUserById(intid) {            returngetSqlSession().selectOne("com.liujie.model.UserMapper.selectUserById",id);      } }

以前的写法：（第一种方式）      <!-- 配置sqlSessionFactory -->      <beanid="sqlSessionFactory"class="org.mybatis.spring.SqlSessionFactoryBean">            <propertyname="dataSource"ref="dataSource"></property>            <propertyname="configLocation"value="classpath:mybatis-config.xml"></property>      </bean>            <beanid="sqlSessionTemplate"class="org.mybatis.spring.SqlSessionTemplate">            <constructor-argindex="0"ref="sqlSessionFactory"></constructor-arg>      </bean>            <beanid="userDao"class="com.liujie.dao.impl.UserDaoImpl">            <propertyname="sqlSession"ref="sqlSessionTemplate"></property>      </bean> publicclass UserDaoImpl implementsUserDao {            privateSqlSessionTemplate sqlSession;            publicvoid setSqlSession(SqlSessionTemplatesqlSession) {            this.sqlSession= sqlSession;      }            publicList<User> selectUser() {            returnsqlSession.selectList("com.liujie.model.UserMapper.selectUser");      }            publicUser selectUserById(intid) {            returnsqlSession.selectOne("com.liujie.model.UserMapper.selectUserById",id);      }       }

明显是简洁了不少。

四、spring整合mybatis第三种方式

     mybatis使用注解（不需要配置user.mapper.xml文件）：

publicinterfaceUserMapper {

     

     @Select("select * from user")

     publicList<User> selectUser();

     

}

publicinterfaceUserService {

     

     publicList<User> selectUser();

     

}

publicclass UserServiceImpl implementsUserService {

     privateUserMapper userMapper;

     

     publicvoid setUserMapper(UserMapperuserMapper) {

           this.userMapper= userMapper;

     }

     publicList<User> selectUser() {

           returnuserMapper.selectUser();

     }

}

     <!-- 配置sqlSessionFactory -->

     <beanid="sqlSessionFactory"class="org.mybatis.spring.SqlSessionFactoryBean">

           <propertyname="dataSource"ref="dataSource"></property>

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

     </bean>

     <beanid="userMapper"class="org.mybatis.spring.mapper.MapperFactoryBean">

           <propertyname="mapperInterface"value="com.liujie.mapper.UserMapper"></property>

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

     </bean>

     

     <beanid="userService"class="com.liujie.service.impl.UserServiceImpl">

           <propertyname="userMapper"ref="userMapper"></property>

     </bean>

五、spring整合mybatis第四种方式（不需要配置mybatis-config.xml文件）

<propertyname="mapperLocations"value="classpath:com/liujie/model/*.mapper.xml"></property>只是改了这里。

     <!-- 配置sqlSessionFactory -->

     <beanid="sqlSessionFactory"class="org.mybatis.spring.SqlSessionFactoryBean">

           <propertyname="dataSource"ref="dataSource"></property>

           <propertyname="mapperLocations"value="classpath:com/liujie/model/*.mapper.xml"></property>

     </bean>

     <beanid="userDao"class="com.liujie.dao.impl.UserDaoImpl">

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

     </bean>

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEmapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

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

<mappernamespace="com.liujie.model.UserMapper">

     <selectid="selectUser"resultType="com.liujie.model.User">

           select * from user

     </select>

     

     <selectid="selectUserById"resultType="com.liujie.model.User">

           select * from user where id = #{id}

     </select>

     <insertid="addUser"parameterType="com.liujie.model.User"useGeneratedKeys="true">

           insert into user(name, pwd) values(#{name}, #{pwd})

     </insert>

     

     <deleteid="remove">

           <!-- 这里故意写错，执行时就会报错 -->

           deletes from user where id = #{id}

     </delete>

     

</mapper>

没有了mybatis-config.xml文件，就不能用别名了，    resultType="com.liujie.model.User"和parameterType="com.liujie.model.User"都要使用类名的全称。

publicclass UserDaoImpl extendsSqlSessionDaoSupport implements UserDao {

     publicList<User> selectUser() {

           returngetSqlSession().selectList("com.liujie.model.UserMapper.selectUser");

     }

     publicUser selectUserById(intid) {

           returngetSqlSession().selectOne("com.liujie.model.UserMapper.selectUserById",id);

     }

}