Spring 事务注意点

 

先看代码

package com.benx.data;

import javax.annotation.Resource;

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

@Service("personService1")
public class PersonServiceImpl1 implements PersonService {

    @Resource
    private PersonDao personDao;

    @Resource(name = "personService1")
    PersonService personService1;

    @Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.NOT_SUPPORTED)
    public void test() {

        personService1.test1();
        test2();
        personService1.test3();
    }

    @Override
    @Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRES_NEW)
    public void test1() {
        personDao.insert(101, "nam101");
    }

    @Override
    @Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
    public void test2() {
        personDao.insert(102, "nam102");
    }

    @Override
    @Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
    public void test3() {
        personDao.insert(103, "nam103");

    }

    @Override
    @Transactional(isolation = Isolation.READ_COMMITTED, propagation = Propagation.REQUIRED)
    public void test4() {
        personDao.insert(104, "nam104");
    }

}

 

测试代码

package com.benx.data;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {

    public static void main(String[] args) {
        
        
        ApplicationContext context = new ClassPathXmlApplicationContext("com/benx/data/spring-data.xml");
        
        
        PersonService service1 = (PersonService) context.getBean("personService1");
        
        
        service1.test();
        
    }
}

 

在 PersonServiceImpl1.test方法中有

personService1.test1();  和 this.test2(); 方法调用，且test1和test2都有@Transactional配置，但是使用personService1.test1()的事务会生效但是this.test()的事务无效，原因是前者会使用到代理但是后者没有。

 

那么为什么一个使用代理一个没有呢？   Spring对于接口的代理默认使用JdkDynamicAopProxy，该类实现InvocationHandler，当调用方法时实际会执行该类的invoke方法，invoke方法会执行拦截方法和target.method方法执行；最后结论就是：

personService1.test1();  相当于JdkDynamicAopProxy.invoke();  invoke内部会执行拦截功能和执行target.test1

this.test2()；相当于target.test();