1.首先自定义一个事务注解(类似于@Transactional)
package com.itmayiedu.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
//事务注解 设置传播行为
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExtTransaction {
}
3.编写切面类AopExtTransaction.java
package com.itmayiedu.aop;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.interceptor.TransactionAspectSupport;
import com.itmayiedu.annotation.ExtTransaction;
import com.itmayiedu.transaction.TransactionUtils;
@Component
@Aspect//自定义事务注解具体实现
public class AopExtTransaction {
@Autowired// 一个事务实例 针对一个事务,所以要在TransactionUtils上加Scope(value="prototype")
private TransactionUtils transactionUtils;
@AfterThrowing("execution(* com.itmayiedu.service.*.*.*(..))")
public void afterThrowing(){
// 获取当前事务进行回滚
TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
}
@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();
commit(transactionStatus);
}
private void commit(TransactionStatus transactionStatus) {
// 5.如果存在注解,提交事务
if(transactionStatus!=null){
transactionUtils.commit(transactionStatus);
}
}
private TransactionStatus begin(ExtTransaction extTransaction) {
if(extTransaction==null){
return null;
}
// 2.如果存在事务注解,开启事务
return transactionUtils.begin();
}
// 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);
Annotation[] declaredAnnotations = objMethod.getDeclaredAnnotations();
ExtTransaction extTransaction=(ExtTransaction) declaredAnnotations[0];
return extTransaction;
}
}
3.UserServiceImpl.java
package com.itmayiedu.service.impl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.interceptor.TransactionAspectSupport;
import com.itmayiedu.annotation.ExtTransaction;
import com.itmayiedu.dao.UserDao;
import com.itmayiedu.service.UserService;
import com.itmayiedu.transaction.TransactionUtils;
@Service
public class UserServiceImpl implements UserService{
@Autowired
private UserDao userDao;
@Autowired
private TransactionUtils transactionUtils;
@ExtTransaction
public void add() {
// 调用接口的时候 接口失败 需要回滚,但是日志记录不需要回滚。
//logService.addLog(); // 后面程序发生错误,不能影响到我的回滚### 正常当addLog方法执行完毕,就应该提交事务
userDao.add("test001", 20);
int i = 1 / 0;
System.out.println("################");
userDao.add("test002", 21);
}
}
4.编写测试类Test01.java
package com.itmayiedu.service;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test01 {
public static void main(String[] args) {
ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring.xml");
UserService userService = (UserService) applicationContext.getBean("userServiceImpl");
userService.add();
}
}
解析:在走useService.add()之前被aop拦截,先走环绕通知(开启事务,提交事务),如果useService.add()里面有异常就走异常通知(回滚事务)