用spring目标对象处理Transaction rolled back because it has been marked as rollback-only

      在使用spring做事务管理时，很多人都会遇到这样一段异常：

org.springframework.transaction.UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only 
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:718) 
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:475) 
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:270) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94) 
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96) 
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260) 
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94) 

 

 

出现上面问题的场景类似下面代码这样：

ITestAService：

 

package com.gigamore.platform.ac.service;
import com.onlyou.framework.exception.BusinessException;
public interface ITestAService {	
	void testA() throws BusinessException;
}

 

 

TestAService：

 

package com.gigamore.platform.ac.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.gigamore.platform.base.service.impl.BaseServiceImpl;
import com.onlyou.framework.exception.BusinessException;
@Service
public class TestAService extends BaseServiceImpl implements ITestAService{
	@Autowired
	private TestBService testBService;
	@Transactional
	public void testA(){
		try{
			testBService.testB();
		}catch(BusinessException e){
		    logger.info(e.getMessage());
		}catch(Exception e){
		    logger.info(e.getMessage());
		}
	}
}

 

 

TestBService：

 

package com.gigamore.platform.ac.service;

import java.util.Date;

import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import com.gigamore.platform.ac.entity.LoanProjectEntity;
import com.gigamore.platform.base.service.impl.BaseServiceImpl;
import com.onlyou.framework.exception.BusinessException;
@Service
public class TestBService extends BaseServiceImpl{
	@Transactional
	public void testB(){
		LoanProjectEntity project = this.selectByPrimaryKey(LoanProjectEntity.class, "2c9483e748321d4601485e1714d31412");
		project.setUpdDataTm(new Date());
		this.update(project);
		throw new BusinessException("抛异常");
	}
}

  测试用例：

 

 

@Autowired
	private ITestAService testAService;
	@Test
	public void testA() {
		testAService.testA();
	}

 

 

     testAService调用testBService的testB()方法，testB()方法里抛了一个BusinessException异常，但是testAService用try{}catch{}捕获异常并不往上层抛了。

     看起来好像没什么问题，异常被捕获了。其实不然，在testAService调用testBService的testB()方法时，会经过一次spring事务控制切面，事务切面里本身会对testBService的testB()方法进行异常捕获： TransactionAspectSupport.invokeWithinTransaction

 

if (txAttr == null || !(tm instanceof CallbackPreferringPlatformTransactionManager)) {
			// Standard transaction demarcation with getTransaction and commit/rollback calls.
			TransactionInfo txInfo = createTransactionIfNecessary(tm, txAttr, joinpointIdentification);
			Object retVal = null;
			try {
				// This is an around advice: Invoke the next interceptor in the chain.
				// This will normally result in a target object being invoked.
				retVal = invocation.proceedWithInvocation();
			}
			catch (Throwable ex) {
				// target invocation exception
				completeTransactionAfterThrowing(txInfo, ex);
				throw ex;
			}
			finally {
				cleanupTransactionInfo(txInfo);
			}
			commitTransactionAfterReturning(txInfo);
			return retVal;
		}

     completeTransactionAfterThrowing(txInfo, ex)里面做了txInfo.getTransactionManager().rollback(txInfo.getTransactionStatus())，事务管理器做rollback, 把事务设置成rollback-only。 以上是testBService外层包装的事务切面做的事情。当testAService的testA()方法执行完，此时执行到testAService外层包装的事务切面，由于testA()方法执行过程没有抛出异常，所以事务正常提交，即执行的是commitTransactionAfterReturning(txInfo)，事务对象txInfo对应的事务管理器进行提交事务，但事务已被设置为rollback-only，故spring对外抛出了Transaction rolled back because it has been marked as rollback-only异常。

    此时如果把testBService的testB方法写在testAService内部，即testA方法里用this.testB()调用，则不会出现以上的问题。因为testAService内方法testA调用方法testB，不会经过spring的事务切面。 由此引发出我用获得目标对象从而绕开spring事务切面的方法来避免该方法。

修改完之后的testAService的testA()：

@Transactional
	public void testA(){
		try{
			//testBService.testB();
			AopTargetUtils.getTarget(testBService).testB();
		}catch(BusinessException e){
		    logger.info(e.getMessage());
		}catch(Exception e){
		    logger.info(e.getMessage());
		}
	}

  AopTargetUtils：根据spring代理对象获取目标对象，spring没有提供相应的工具类，以下代码是网上找的，我加上了泛型约束，用反射获得代理类内部的目标对象。

package com.gigamore.platform.ac.service;

import java.lang.reflect.Field;
import org.springframework.aop.support.AopUtils;
import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopProxy;

public class AopTargetUtils {  
	  
    
    /** 
     * 获取 目标对象 
     * @param proxy 代理对象 
     * @return  
     * @throws Exception 
     */  
    public static <T> T getTarget(T proxy) throws Exception {  
          
        if(!AopUtils.isAopProxy(proxy)) {  
            return proxy;//不是代理对象  
        }  
          
        if(AopUtils.isJdkDynamicProxy(proxy)) {  
            return (T)getJdkDynamicProxyTargetObject(proxy);  
        } else { //cglib  
            return (T)getCglibProxyTargetObject(proxy);  
        }  
          
          
          
    }  
  
  
    private static Object getCglibProxyTargetObject(Object proxy) throws Exception {  
        Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");  
        h.setAccessible(true);  
        Object dynamicAdvisedInterceptor = h.get(proxy);  
          
        Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");  
        advised.setAccessible(true);  
          
        Object target = ((AdvisedSupport)advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();  
          
        return target;  
    }  
  
  
    private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {  
        Field h = proxy.getClass().getSuperclass().getDeclaredField("h");  
        h.setAccessible(true);  
        AopProxy aopProxy = (AopProxy) h.get(proxy);  
          
        Field advised = aopProxy.getClass().getDeclaredField("advised");  
        advised.setAccessible(true);  
          
        Object target = ((AdvisedSupport)advised.get(aopProxy)).getTargetSource().getTarget();  
          
        return target;  
    }  
      
}  

    这样，testAService调用testBService时，则类似Service内部的方法调用，不会经过spring事务切面，且此时testAService和testBService都在同一个事务里面，testBService的操作不会被回滚。

    不过，这样会引发一个问题，我们不仅绕过了spring的事务切面，也绕过了spring的其他的AOP切面，如果有用spring做日志记录之类的AOP处理，在执行testBService的testB()方法时，则不会做日志记录的处理。

    看了下评论里哥们说的用嵌套事务去处理这种情况，把TestBService
 的testB()方法的事务注解改成@Transactional(propagation = Propagation.NESTED)，确实可以达到避免异常的效果。推荐用嵌套事务这种方法。本文中的方法有很大的局限性，仅仅可作为解决问题的一个思路。