第四天：实现简单的更新用户信息功能

开发环境

• 64位的Windows系统
• Server version: 5.5.58
• MySQL Community Server (GPL)
• java version “1.8.0_211”
• SQLyog
• IDEA
• Apache Maven 3.6.0

具体实现

.java文件

//UserDao.java
package com.ldb.dao;

import com.ldb.bean.User;

import java.util.List;

//UserDao -- 数据库交互层
public interface UserDao {
   
   

    //查询全部; ListUser user = new ArrayList<>()
    List<User> findAllUser();

    //添加用户
    int save(User user);
    
    //删除用户
    int delete(User user);
	
    //更新用户
    int update(User user);
}

//UserService.java
package com.ldb.service;

import com.ldb.bean.User;

import java.util.List;

//业务逻辑层
public interface UserService {
   
   
    // 查询全部
    List<User> findAllUser();

    //添加用户
    int save(User user);
    
    //删除用户
    int delete(User user);
    
    //更新用户
    int update(User user);
}

//UserServiceImpl.java
package com.ldb.service.impl;

import com.ldb.bean.User;
import com.ldb.dao.UserDao;
import com.ldb.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
//Spring通过扫描注解来控制每个层，告诉Spring这里是service层
public class UserServiceImpl implements UserService {
   
   

    @Autowired
    //自动注入注解
    private UserDao userDao;

    @Override
    //查询全部
    public List<User> findAllUser() {
   
   
        return userDao.findAllUser();
    }

    @Override
    //添加用户
    public int save(User user) {
   
   
        return userDao.save(user);
    }

    //删除用户
    public int delete(User user){
   
   
        return userDao.delete(user);
    }
    
    //更新用户
    public int update(User user){
   
   
        return userDao.update(user);
    }
}

//UserController.java
package com.ldb.controller;


import com.ldb.bean.User;
import com.ldb.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import or