spring Aop 切面编程完成转账事务处理

1. 封装 around 方法 注意参数:ProceedingJoinPoint point

@Component
public class TransciationUtil {

    @Autowired
    private ConnectionHolder connectionHolder;

    public void start() throws SQLException {
        connectionHolder.getConnection().setAutoCommit(false);
    }

    public void commit() throws SQLException {
        connectionHolder.getConnection().commit();
    }

    public void rollback()  {
        try {
            connectionHolder.getConnection().rollback();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void close(){
        try {
            connectionHolder.getConnection().close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

//参数ProceedingJoinPoint: 代表调用对象方法本身
// point.proceed()方法代表执行原本代理方法, 可以在此方法前后进行自己需要的操作
    public void around(ProceedingJoinPoint point){
        try {
            start();
            point.proceed();
            commit();
        } catch (Throwable throwable) {
            rollback();
            throwable.printStackTrace();
        }finally {
            close();
        }
    }

}

2. 配置 pom.xml 文件: 导入 spring-aop 包和 aspecj 切面编程的三方包

      <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aop</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>
        <!--
          逻辑织入功能模块
         第三方提供了
         -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.4</version>
        </dependency>

3. 配置全局配置文件:

    <aop:config>
// ref 指向配置织入方法的文件
        <aop:aspect id="t" ref="transciationUtil">
// aop:around  配置文件中织入的方法名,  以及切入点execution(* com.lily.service..*.*(..))"
            <aop:around method="around" pointcut="execution(* com.lily.service..*.*(..))" />
        </aop:aspect>

    </aop:config>

execution(* com.lily.service...(..)) 通配符: (..)代表任何一个方法

4. AccountServiceImpl

@Component("accountService")
public class AccountServiceImpl implements AccountService {

    @Resource
    private AccountDao accountDao;

    @Override
    public void transfer(String fromUser, String toUser, double money) {
        accountDao.update(fromUser, -money);
        int i = 4/0;
        accountDao.update(toUser, money);
    }
}

5. 测试

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class MyTest01 {


    @Autowired
    private AccountService accountService;

    @Test
    public void testTransfer2(){
        accountService.transfer("小明","小李",100);
    }
}

数据库金额未发生非同步变化

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使用注解开发时:
注解配置文件需要配置: @EnableAspectJAutoProxy //开启使用切面编程
提供直接的切面类 @Aspect
方法: @Around("xx") xx为切入点, 例如:execution(* com.lily.service...(..))"

@Component
@Aspect
public class TransciationUtil {

   @Around("execution(* com.lily.service..*.*(..))")
   public void around(ProceedingJoinPoint point){
       try {
           start();
           point.proceed();
           commit();
       } catch (Throwable throwable) {
           rollback();
           throwable.printStackTrace();
       }finally {
           close();
       }
   }
}