Spring自定义注解实现事务

首先spring中事务有两种方式：编程事务、声明事务

编程事务：

获取项目中事务管理器 DataSourceTransactionManager

采用事务管理提交回滚操作

@Component
public class TransactionUtils {
    @Autowired
    private DataSourceTransactionManager dataSourceTransactionManager;
    //获取当前事务
    public TransactionStatus begin(){
        //采用默认传播行为
        TransactionStatus transaction = dataSourceTransactionManager.getTransaction(new DefaultTransactionAttribute());
        return transaction;
    }
    //提交
    public void commit(TransactionStatus transaction){
        dataSourceTransactionManager.commit(transaction);
    }
    public void rollback(TransactionStatus transaction){
        dataSourceTransactionManager.rollback(transaction);
    }
}

业务层

@RestController
public class TxServiceImpl {
    @Autowired
    private TransactionUtils transactionUtils;
    //采取事务
    @GetMapping("/tx")
    public String insertUser(User user){
        TransactionStatus begin == null;
        //begin开启事务，若不提交相当于对数据使用行锁
        try {
            begin = transactionUtils.begin();
            String res = userMapper.insert(user)>0?"成功":"失败";
            int j = 1/user.getUserId();
            transactionUtils.commit(begin);
            return res;
        }catch (Exception e){
            if (begin != null){
                transactionUtils.rollback(begin);
                return "系统错误";
            }

        }
    }
}

代码重复性强，扩展性好

声明事务：

只需要加入注解 @Transactional

当方法执行完，aop采取拦截，判断成功还是异常采取对应的操作

失效问题：

当方法中用try捕获异常，异常不会抛到aop，则不会回滚，

需要手动回滚在catch中使用

TransactionAspectSupport.currentTransactionStatus().set
RollbackOnly();

自定义注解

创建注解

//作用范围
@Target({ElementType.METHOD,ElementType.TYPE})
//通过反射机制获取注解
@Retention(RetentionPolicy.RUNTIME)
@Inherited
//注释文档
@Documented
public @interface MyTransactional {
}

定义aop拦截方法

@Component
@Aspect
public class ExtTransactionalAop {
    @Autowired
    private TransactionUtils transactionUtils;
    //拦截方法上有自定义注解 走环绕通知
    @Around(value = "@annotation(com.lzq.aop.MyTransactional)")
    public Object around(ProceedingJoinPoint joinPoint){
        TransactionStatus begin = null;
        try {
            begin = transactionUtils.begin();
            //获取目标方法
            Object res = joinPoint.proceed();
            transactionUtils.commit(begin);
            return res;
        } catch (Throwable throwable) {
            throwable.printStackTrace();
            if (begin != null){
                transactionUtils.rollback(begin);
            }
            return "系统错误";
        }
    }
}

此时将自定义注解加在方法上即可

Spring自定义注解实现事务

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