@Target(value = { ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
public @interface AddAnnotation {int userId() default 0;String userName() default "默认名称";String[]arrays();
}
反射读取注解信息public static void main(String[] args) throws ClassNotFoundException {Class classInfo = Class.forName("com.entity.User");// 获取到所有方法Method[] methods = classInfo.getDeclaredMethods();for (Method method : methods) {System.out.println(method);　　　　　　　　//查看该方法是否存在注解AddAnnotation declaredAnnotation = method.getDeclaredAnnotation(AddAnnotation.class);if (declaredAnnotation == null) {// 结束本次循环continue;}// 获取userIdint userId = declaredAnnotation.userId();System.out.println("userId:" + userId);// 获取userNameString userName = declaredAnnotation.userName();System.out.println("userName:" + userName);// 获取arraysString[] arrays = declaredAnnotation.arrays();for (String str : arrays) {System.out.println("str:" + str);}}}

//编程事务（需要手动begin 手动回滚  手都提交）
@Component()
@Scope("prototype") // 设置成原型解决线程安全
public class TransactionUtils {private TransactionStatus transactionStatus;// 获取事务源
    @Autowiredprivate DataSourceTransactionManager dataSourceTransactionManager;// 开启事务public TransactionStatus begin() {transactionStatus = dataSourceTransactionManager.getTransaction(new DefaultTransactionAttribute());return transactionStatus;}// 提交事务public void commit(TransactionStatus transaction) {dataSourceTransactionManager.commit(transaction);}// 回滚事务public void rollback() {System.out.println("rollback");dataSourceTransactionManager.rollback(transactionStatus);}}注解类@Autowiredprivate TransactionUtils transactionUtils;@AfterThrowing("execution(* com.itmayiedu.service.*.*.*(..))")public void afterThrowing() throws NoSuchMethodException, SecurityException {// isRollback(proceedingJoinPoint);System.out.println("程序发生异常");// TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();// TransactionStatus currentTransactionStatus =// TransactionAspectSupport.currentTransactionStatus();// System.out.println("currentTransactionStatus:" +// currentTransactionStatus);
        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 proceedingJoinPoint) throws Throwable {// 调用方法之前执行TransactionStatus transactionStatus = begin(proceedingJoinPoint);proceedingJoinPoint.proceed();// 代理调用方法 注意点： 如果调用方法抛出异常不会执行后面代码// 调用方法之后执行
        commit(transactionStatus);}public TransactionStatus begin(ProceedingJoinPoint pjp) throws NoSuchMethodException, SecurityException {// // 判断是否有自定义事务注解ExtTransaction declaredAnnotation = getExtTransaction(pjp);if (declaredAnnotation == null) {return null;}// 如果有自定义事务注解，开启事务System.out.println("开启事务");TransactionStatus transactionStatu = transactionUtils.begin();return transactionStatu;}public void commit(TransactionStatus transactionStatu) {if (transactionStatu != null) {// 提交事务System.out.println("提交事务");transactionUtils.commit(transactionStatu);}}public ExtTransaction getExtTransaction(ProceedingJoinPoint pjp) throws NoSuchMethodException, SecurityException {// 获取方法名称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);// // 判断是否有自定义事务注解ExtTransaction declaredAnnotation = objMethod.getDeclaredAnnotation(ExtTransaction.class);if (declaredAnnotation == null) {System.out.println("您的方法上,没有加入注解!");return null;}return declaredAnnotation;}// 回滚事务public void isRollback(ProceedingJoinPoint pjp) throws NoSuchMethodException, SecurityException {// // 判断是否有自定义事务注解ExtTransaction declaredAnnotation = getExtTransaction(pjp);if (declaredAnnotation != null) {System.out.println("已经开始回滚事务");// 获取当前事务 直接回滚
            TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();return;}}使用自定义注解@ExtTransaction
public void add() {
userDao.add("test001", 20);
int i = 1 / 0;
System.out.println("################");
userDao.add("test002", 21);
}