.UserDao">
<update id="updateBalance">
update t_user set balance=balance+#{money} where id=#{id}
</update>
</mapper>
（4）service
package com.ddd.service.impl;
import com.ddd.dao.UserDao;
import com.ddd.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
@Service
public class UserServieImpl implements UserService {
@Autowired
private UserDao userDao;
@Transactional //该方法交于spring的事务来管理了---默认spring不识别该注解
public void zhuanzhang(int id, int uid, double money) {
//1.扣钱
userDao.updateBalance(id,-money);
//int c=10/0;
//2.收钱
userDao.updateBalance(uid,money);
}
}
(5)测试:
public class Test {
public static void main(String[] args) {
ApplicationContext app=new ClassPathXmlApplicationContext("classpath:spring.xml");
UserService userServieImpl = (UserService) app.getBean("userServieImpl");
userServieImpl.zhuanzhang(7,6,400);
}
}