spring 事务注意事项 -- 事务注解一定写到service最外层

事务采用的是注解方式。

持久层用的是MyBatis，简单配置如下：

 <!--数据源配置, 使用 Druid 数据库连接池--><bean id="mysqlDataSource" class="com.alibaba.druid.pool.DruidDataSource"  destroy-method="close">    <qualifier value="dataSource"/>    <!-- 基本属性 url、user、password -->    <property name="url" value="${mysql.database.url}"/>    <property name="username" value="${mysql.database.user}"/>    <property name="password" value="${mysql.database.password}"/>    <!-- 配置初始化大小、最小、最大 -->    <property name="initialSize" value="5"/>    <property name="minIdle" value="${mysql.database.minIdle}"/>    <property name="maxActive" value="${mysql.database.maxActive}"/>    <!-- 配置获取连接等待超时的时间 -->    <property name="maxWait" value="60000"/>    <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->    <property name="timeBetweenEvictionRunsMillis" value="60000"/>    <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->    <property name="minEvictableIdleTimeMillis" value="300000"/>    <property name="validationQuery" value="SELECT 1 FROM DUAL" />    <property name="testWhileIdle" value="true"/>    <property name="testOnBorrow" value="false"/>    <property name="testOnReturn" value="false"/>    <!-- 配置监控统计拦截的filters -->    <property name="filters" value="stat"/></bean>

<!-- mybatis文件配置，扫描所有mapper文件 --><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">    <property name="dataSource" ref="mysqlDataSource"/>    <property name="typeAliasesPackage" value="com.xxxxx.model"/>    <property name="configLocation" value="classpath:/conf/mybatis/mybatis-config.xml"/>    <!-- 自动扫描映射文件 -->    <property name="mapperLocations">        <list>            <value>classpath:/mappers/*.xml</value>        </list>    </property></bean><!-- spring与mybatis整合配置，扫描所有dao --><!-- 扫描basePackage下所有以@MyBatisRepository注解的接口--><bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">    <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>    <property name="basePackage" value="com.xxxxx.dao"/></bean>
 <!-- mysqlServer事务，注意 使用此事务时需要显示写明Transaction(value="txMysqlManager")-->   <bean id="txMysqlManager"  class="org.springframework.jdbc.datasource.DataSourceTransactionManager">       <property name="dataSource" ref="mysqlDataSource" />   </bean>   <!-- 事务控制   --> <!-- mysqlServer事务，注意 使用此事务时需要显示写明Transaction(value="txMysqlManager")--><tx:annotation-driven transaction-manager="txMysqlManager" proxy-target-class="true" order="50"/>

controller代码如下：

@RequestMapping(value="/testTransaction", method={RequestMethod.GET, RequestMethod.POST})public  void  testTransaction() {   try {      ybsTrainingService.commitTransactionBase();   } catch (Exception e) {      logger.info("测试内容失败", e);   }}

servce代码如下：

@Transactional(value = "txMysqlManager", rollbackFor = Exception.class)public void commitTransactionBase() {    commitTransaction();}private void commitTransaction() {    TrainingState trainingState = new TrainingState();
    trainingState.setTrainingId(220);
    trainingState.setTrainingState(1);   //数据库上是3    trainingMapper.updateTrainingState(ybsTrainingState);    CourseState ybsCourseState = new CourseState();    courseState.setCourseState(1);       //数据库上是2        courseState.setId(9348172);    courseMapper.updateCourseState(ybsCourseState);   //如下两行是异常测试 ，会报空指针异常

    ybsCourseState = null;    ybsCourseState.setCourseState(1);}

注意：如果将 “@Transactional(value ="txMysqlManager", rollbackFor = Exception.class)” 放到子方法commitTransaction()上边，如下，则事务不会起作用。

public void commitTransactionBase() {    commitTransaction();}

@Transactional(value = "txMysqlManager", rollbackFor = Exception.class)private void commitTransaction() {   
    TrainingState trainingState = new TrainingState();
    trainingState.setTrainingId(220);
    trainingState.setTrainingState(1);   //数据库上是3
    trainingMapper.updateTrainingState(ybsTrainingState);
    CourseState ybsCourseState = new CourseState();
    courseState.setCourseState(1);       //数据库上是2  
    courseState.setId(9348172);    
    courseMapper.updateCourseState(ybsCourseState);   
    //如下两行是异常测试 ，会报空指针异常
    ybsCourseState = null;    ybsCourseState.setCourseState(1);
}

补充，最外层service方法，在这里边是commitTransactionBase() 方法，就是被controller直接调用的。所以肯定是public 修饰，如果是私有private修饰 ，则事务也不会生效，当然正常情况下，controller也不会调用到其他类的private方法。