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springboot 使用mybatis查询的示例代码

2024-04-02 19:55

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springboot 使用mybatis查询的示例代码

示例1

项目结构

代码controller中 UserController.java

package com.example.demo1110.controller;

import com.example.demo1110.entity.User;
import com.example.demo1110.service.UserService;
import org.apache.ibatis.annotations.Param;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/user")
@CrossOrigin //解决跨域名获取
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping("/all")
    public List<User> getListUser(){
        return userService.listUser();
    }

    @GetMapping("/getId/id={id}")
    private User getId(@PathVariable("id") Integer id){
        return userService.queryById(id);
    }

    @PostMapping("/EditUser")
    private Map<String,Object> editUser(@RequestBody User user){
        System.out.println(user);
        HashMap<String,Object> map = new HashMap<>();
        try {
            userService.editUser(user);
            map.put("success",true);
            map.put("msg","修改员工成功");
        }catch (Exception e){
            e.printStackTrace();
            map.put("success",false);
            map.put("msg","修改员工失败");
        }
        return map;
    }

    @GetMapping("/getName")
    public List<User> getName(@Param("name") String name){
        return userService.queryByName(name);
    }

    @PostMapping("/addUser")
    public Map<String,Object> addUser(@RequestBody User user){
        HashMap<String,Object> map = new HashMap<>();
        try {
            userService.addUser(user);
            map.put("success",true);
            map.put("msg","添加员工成功");
        }catch (Exception e){
            e.printStackTrace();
            map.put("success",false);
            map.put("msg","添加用户失败");
        }
        return map;
    }

    @GetMapping("/deletUser/{id}")
    public  Map<String,Object> deletUser(@PathVariable("id") Integer id){
        System.out.println(id);
        HashMap<String,Object> map = new HashMap<>();
        try {
            userService.deleteUserById(id);
            map.put("success",true);
            map.put("msg","删除员工成功");
        }catch (Exception e){
            e.printStackTrace();
            map.put("success",false);
            map.put("msg","删除用户失败");
        }
        return map;
    }
}

entity中 User.java

package com.example.demo1110.entity;
import lombok.Data;
@Data
public class User {
    private int id;
    private String name;
    private int age;
    private String city;
}

mapper中 UserDao.java

package com.example.demo1110.mapper;
import com.example.demo1110.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;
@Mapper
@Repository
public interface UserDao {
    //查询所有记录
    public List<User> listUser();
    //按id查询
    public User queryById(Integer id);
    //按姓名模糊查询
    public List<User> queryByName(String name);

    //保存用户
    public int addUser(User user);
    //根据员工id删除
    public int deleteUserById(Integer id);
    //修改员工信息
    public int editUser(User user);
}

service中 UserService.java

package com.example.demo1110.service;

import com.example.demo1110.entity.User;

import java.util.List;

public interface UserService {
    //查询所有记录
    public List<User> listUser();
    //按id查询
    public User queryById(Integer id);
    //按姓名模糊查询
    public List<User> queryByName(String name);

    //保存用户
    public boolean addUser(User user);

    //根据员工id删除
    public boolean deleteUserById(Integer id);

    //修改员工信息
    public boolean editUser(User user);
}

service impl中 UserServiceImpl.java

package com.example.demo1110.service.impl;

import com.example.demo1110.entity.User;
import com.example.demo1110.mapper.UserDao;
import com.example.demo1110.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserDao userDao;

    @Override
    public List<User> listUser() {
        return userDao.listUser();
    }

    @Override
    public User queryById(Integer id) {
        return userDao.queryById(id);
    }

    @Override
    public List<User> queryByName(String name) {
        return userDao.queryByName(name);
    }

    @Override
    public boolean addUser(User user) {
        int i = userDao.addUser(user);
        if(i > 0){
            return true;
        }else {
            return false;
        }
    }

    @Override
    public boolean deleteUserById(Integer id) {
        int i = userDao.deleteUserById(id);
        if(i > 0){
            return true;
        }else {
            return false;
        }
    }

    @Override
    public boolean editUser(User user) {
        int i = userDao.editUser(user);
        if(i > 0){
            return true;
        }else {
            return false;
        }
    }
    
}

主java文件 Demo1110Application.java

package com.example.demo1110;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@MapperScan("com.example.demo1110.mapper")
@SpringBootApplication
public class Demo1110Application {

    public static void main(String[] args) {
        SpringApplication.run(Demo1110Application.class, args);
    }

}

UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.demo1110.mapper.UserDao">
    <select id="listUser" resultType="com.example.demo1110.entity.User">
        select * from user
    </select>

    <select id="queryById" parameterType="int" resultType="com.example.demo1110.entity.User">
        select * from user
        where id = #{id}
    </select>

    <select id="queryByName" parameterType="String" resultType="com.example.demo1110.entity.User">
        select * from user
        where username = #{name}
    </select>

    <insert id="addUser" parameterType="com.example.demo1110.entity.User">
        insert  into user values (#{id},#{username},#{age},#{city})
    </insert>

    <delete id="deleteEmployeeById" parameterType="int">
        delete from user where id = #{id}
    </delete>

    <update id="editEmployee" parameterType="com.example.demo1110.entity.User">
        update user
        set username = #{name},age = #{age},city = #{city}
        where id = #{id}
    </update>
</mapper>

application.yml

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/mybatisdemo?characterEncoding=utf-8&useSSL=false
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  mapper-locations: classpath*:mapper/查询所有记录
    public List<User> listUser();
    //按id查询
    public User queryById(Integer id);
    //按姓名模糊查询
    public List<User> queryByName(String name);

    //保存用户
    public int addUser(User user);
    //根据员工id删除
    public int deleteUserById(Integer id);
    //修改员工信息
    public int editUser(User user);*/
    
    List<User> findAllUser();


    
    User findUser(Integer id);


    
    void insertUser(User user);


    
    void deleteUser(Integer id);


    
    void updateUser(User user);
    

    void deleteUserByList(Integer[] ids);
}

service -> UserService.java

package com.example.demo1110.service;
import com.example.demo1110.entity.User;
import java.util.List;
public interface UserService {
    
    
    List<User> findAll();
    
    User findUserById(Integer id);
    
    void  insertUser(User user);
    
    void updateUser(User user);
    
    void deleteUser(Integer id);
    void deleteUserByList(Integer[] ids);
}

service impl ->UserServiceImpl.java

package com.example.demo1110.service.impl;
import com.example.demo1110.entity.User;
import com.example.demo1110.mapper.UserMapper;
import com.example.demo1110.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class UserServiceImpl implements UserService {
    
    @Autowired
    private UserMapper userMapper;
    @Override
    public User findUserById(Integer id) {
        return userMapper.findUser(id);
    }
    @Override
    public List<User> findAll() {
        return userMapper.findAllUser();
    }
    @Override
    public void insertUser(User user) {
        userMapper.insertUser(user);
    }
    @Override
    public void updateUser(User user) {
        userMapper.updateUser(user);
    }
    @Override
    public void deleteUser(Integer id) {
        userMapper.deleteUser(id);
    }
    @Override
    public void deleteUserByList(Integer[] ids) {
        userMapper.deleteUserByList(ids);
    }
}

controller ->UserController.java

package com.example.demo1110.controller;

import com.example.demo1110.entity.User;
import com.example.demo1110.service.UserService;
import org.apache.ibatis.annotations.Param;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/user")
@CrossOrigin //解决跨域名获取
public class UserController {
    
    @Autowired
    private UserService userService;

    @GetMapping("/{id}")
    public User findUserByid(@PathVariable("id") Integer id){
        return userService.findUserById(id);
    }

    @GetMapping("/findAll")
    public List<User> findAll(){
        return userService.findAll();
    }

    @PostMapping("/add")
    // // post转实体对象   只能用raw   application/json格式传参   key-value跟实体对应 controller用@RequestBody
    public void insertUser(@RequestBody  User user){
        userService.insertUser(user);
    }

    @PutMapping("/update")
    public void updateUser(@RequestBody  User user){
        userService.updateUser(user);
    }

    @DeleteMapping("/delete/{id}")
    public void deleteUser(@PathVariable("id") Integer id){
        userService.deleteUser(id);
    }

    @DeleteMapping("/deleteBatch")
    public void deleteBatch(@RequestBody Integer[] ids){
        userService.deleteUserByList(ids);
    }
}

controller ->IndexController.java

package com.example.demo1110.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController

public class IndexController {
    @RequestMapping ("/")
    String home () {
        return "hello world!!";
    }
}

resources mapper -> UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--<mapper namespace="com.example.demo1110.mapper.UserMapper">
    <select id="listUser" resultType="com.example.demo1110.entity.User">
        select * from user
    </select>

    <select id="queryById" parameterType="int" resultType="com.example.demo1110.entity.User">
        select * from user
        where id = #{id}
    </select>

    <select id="queryByName" parameterType="String" resultType="com.example.demo1110.entity.User">
        select * from user
        where username = #{name}
    </select>

    <insert id="addUser" parameterType="com.example.demo1110.entity.User">
        insert  into user values (#{id},#{username},#{age},#{city})
    </insert>

    <delete id="deleteEmployeeById" parameterType="int">
        delete from user where id = #{id}
    </delete>

    <update id="editEmployee" parameterType="com.example.demo1110.entity.User">
        update user
        set username = #{name},age = #{age},city = #{city}
        where id = #{id}
    </update>
</mapper>-->
<mapper namespace="com.example.demo1110.mapper.UserMapper">
    <resultMap id="user" type="com.example.demo1110.entity.User">
        <id column="id" property="id"/>
        <result column="age" property="age"/>
        <result column="name" property="name"/>
    </resultMap>
    <select id="findUser" parameterType="int" resultMap="user">
        select * from user
        <where>
            <if test="_parameter!=null">
                and id = #{id}
            </if>
        </where>
    </select>

    <select id="findAllUser" resultMap="user">
        select * from user
    </select>

    <sql id="key">
        <trim suffixOverrides=",">
            <if test="id!=null">
                id,</if>
            <if test="name!=null">
                name,
            </if>

            <if test="age!=null">
                age,
            </if>
        </trim>
    </sql>
    <sql id="value">
        <trim suffixOverrides=",">
            <if test="id!=null">
                #{id},
            </if>
            <if test="name!=null">
                #{name},
            </if>
            <if test="age!=null">
                #{age},
            </if>
        </trim>
    </sql>

    <insert id="insertUser" parameterType="user">
        insert into user(<include refid="key"/>) values (<include refid="value"/>)
    </insert>

    <update id="updateUser" parameterType="user">
        UPDATE user
        <trim prefix="set" suffixOverrides=",">
            <if test="age!=null">age=#{age},</if>
            <if test="name!=null and name !=''">name=#{name},</if>
        </trim>
        WHERE id=#{id}

    </update>
    <delete id="deleteUser" parameterType="Integer">
        delete  from user where id = #{id}
    </delete>

    <delete id="deleteUserByList">
        delete  from user where id in
        <foreach collection="array" open="(" close=")" separator="," item="id">
            #{id}
        </foreach>
    </delete>

</mapper>

测试运行项目

http://127.0.0.1:8080/user/findAll

返回数据

[{"id":1,"name":"小明","age":18,"city":"深圳"},{"id":2,"name":"小明1","age":18,"city":"深圳"}]

源代码

链接: https://pan.baidu.com/s/11CVG6FyWrm67HR_ONVnVYw

提取码: tdfr

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