JPA service里面的两个文件

package com.hunqing.user.service;

import com.hunqing.user.entity.User;

/**
* 用户操作接口
*
* @author
*
*

Modification History:

Date Author Description

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}package com.hunqing.user.service;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

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

import com.hunqing.user.entity.User;

@Service @Transactional
public class UserService implements IUserService {

@PersistenceContext
EntityManager em;

public void delete(String userName) { //throws XXX //抛出的例外叫用户例外，客户端捕获
//运行期的异常叫运行期例外 spring会捕获运行期例外，自动回滚事物
//客户例外不会回滚事物

em.remove(em.getReference(User.class, userName));
}

public User find(String userName) {
return em.find(User.class,userName);
}

public void save(User user) {

em.persist(user);
}

public void update(User user) {
em.merge(user);

}

}