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手动事务

@Component
@Scope("prototype") // 每个事务都是新的实例 目的解决线程安全问题 多例子
public class TransactionUtils {
    // 全局接受事务状态
    private TransactionStatus transactionStatus;
    // 获取事务源
    @Autowired
    private DataSourceTransactionManager dataSourceTransactionManager;
    // 开启事务
    public TransactionStatus begin() {
        System.out.println("开启事务");
        //DefaultTransactionAttribute定义了传播属性和隔离机制
        transactionStatus = dataSourceTransactionManager.getTransaction(new DefaultTransactionAttribute());
        return transactionStatus;
    }
    // 提交事务
    public void commit(TransactionStatus transaction) {
        System.out.println("提交事务");
        dataSourceTransactionManager.commit(transaction);
    }
    // 回滚事务
    public void rollback() {
        System.out.println("回滚事务...");
        dataSourceTransactionManager.rollback(transactionStatus);
    }
}
// 代码样例
public void add() {
        TransactionStatus transactionStatus = null;
        try {
            // 开启事务
            transactionStatus = transactionUtils.begin();
            userDao.add("test001", 20);
            System.out.println("开始报错啦!@!!");
            int i = 1 / 0;
            System.out.println("################");
            userDao.add("test002", 21);
            // 提交事务
            if (transactionStatus != null)
                transactionUtils.commit(transactionStatus);
        } catch (Exception e) {
            e.getMessage();
            // 回滚事务
            if (transactionStatus != null)
                transactionUtils.rollback(transactionStatus);
        }
    }

自定义注解事务

//自定义注解
@Target({ ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
public @interface ExtTransaction {
}
//AOP+手动事务
@Aspect
@Component
public class AopExtTransaction {
    @Autowired
    private TransactionUtils transactionUtils;
    // 使用异常通知进行 回滚事务
    @AfterThrowing("execution(* com.itmayiedu.service.*.*.*(..))")
    public void afterThrowing() {
        // TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
        transactionUtils.rollback();
    }

    // 环绕通知 在方法之前和之后处理事情
    @Around("execution(* com.itmayiedu.service.*.*.*(..))")
    public void around(ProceedingJoinPoint pjp) throws Throwable {

        // 1.获取该方法上是否加上注解
        ExtTransaction extTransaction = getMethodExtTransaction(pjp);
        TransactionStatus transactionStatus = begin(extTransaction);
        // 2.调用目标代理对象方法
        pjp.proceed();
        // 3.判断该方法上是否就上注解
        commit(transactionStatus);
    }

    private TransactionStatus begin(ExtTransaction extTransaction) {
        if (extTransaction == null) {
            return null;
        }
        return transactionUtils.begin();
    }

    private void commit(TransactionStatus transactionStatus) {
        if (transactionStatus != null) {
            transactionUtils.commit(transactionStatus);
        }
    }

    // 获取方法上是否存在事务注解
    private ExtTransaction getMethodExtTransaction(ProceedingJoinPoint pjp)
            throws NoSuchMethodException, SecurityException {
        String methodName = pjp.getSignature().getName();
        // 获取目标对象
        Class<?> classTarget = pjp.getTarget().getClass();
        // 获取目标对象类型
        Class<?>[] par = ((MethodSignature) pjp.getSignature()).getParameterTypes();
        // 获取目标对象方法
        Method objMethod = classTarget.getMethod(methodName, par);
        ExtTransaction extTransaction = objMethod.getDeclaredAnnotation(ExtTransaction.class);
        return extTransaction;
    }
}
//注解使用
@ExtTransaction
    public void add() {
        userDao.add("test001", 20);
        // int i = 1 / 0;
        System.out.println("################");
        userDao.add("test002", 21);
    }

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