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springboot+mybatis实现数据增删改查

2020-02-04 11:37:38 作者：互联网

springboot+mybatis实现数据增删改查

上一篇讲到使用idea创建springboot项目那么下面我们来讲讲使用mybatis实现增删改查(curd)吧。

1、数据库创建

2、pom.xml文件加入依赖mysql 等等

 <!--mysql依赖-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

3、在配置文件（application.yml）中加入数据库的配置 注意用户名、密码、库名、包名路径改成自己的

server:
  port: 8111
  servlet:
    context-path: /

spring:
  datasource:
    username: root
    password: '*******'
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/lzw?serverTimezone=UTC&useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&failOverReadOnly=false

mybatis:
  mapper-locations: classpath:./mapper/*Mapper.xml
  type-aliases-package: com.example.bys.entity

4、在src文件夹下新建UserEntity类与数据库的字段对应

package com.example.bys.entity;

public class UserEntity {
    private int userid;
    private String username;
    private String password;
    private String email;

    public UserEntity(String username, String password, String email) {
        this.userid = userid;
        this.username = username;
        this.password = password;
        this.email = email;
    }

    public UserEntity() {
    }

    public int getUserid() {
        return userid;
    }

    public void setUserid(int userid) {
        this.userid = userid;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

5、新建mapper文件夹并新建UserMapper接口

package com.example.bys.mapper;

import com.example.bys.entity.UserEntity;
import org.apache.catalina.User;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface UserMapper {
    /**
     *
     * @return 查询所有用户
     */
    List<UserEntity> selectAllUser();

    /**
     *
     * @param id 用户id
     * @return 查询单个用户
     */
    UserEntity selectOneUser(int id);

    /**
     *
     * @param userEntity 插入用户
     * @return 插入的用户
     */
    void insertUser(UserEntity userEntity);

    /**
     *
     * @param id 删除用户的id
     */
    void deleteUser(int id);

    /**
     *
     * @param userEntity 更新用户的数据
     */
    void updateUser(UserEntity userEntity);
}

6、新建service文件夹并新建UserServiceImpl类去实现上面的mapper接口

package com.example.bys.service;


import com.example.bys.entity.UserEntity;
import com.example.bys.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl {

    @Autowired
    UserMapper userMapper;

    public List<UserEntity> selectAllUser() {
        return userMapper.selectAllUser();
    }

    public UserEntity selectOneUser(int id) {
        return userMapper.selectOneUser(id);
    }
    public void insertUser(UserEntity userEntity){
        userMapper.insertUser(userEntity);
    }
    public void deleteUser(int id){
        userMapper.deleteUser(id);
    }
    public void updateUser(UserEntity userEntity){
        userMapper.updateUser(userEntity);
    }


}

7、在controller文件夹下新建UserController类在里面写对应的逻辑

package com.example.bys.controller;

import com.example.bys.entity.UserEntity;
import com.example.bys.service.UserServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserServiceImpl userService;

    @RequestMapping("/selectAllUser")
    public List<UserEntity> selectAllUser(){
        return userService.selectAllUser();
    }

    @RequestMapping("/selectOneUser")
    public UserEntity selectOneUser(int id){
        return userService.selectOneUser(id);
    }

    @PostMapping("/insertUser")
    public void insertUser(@RequestBody UserEntity userEntity){
         userService.insertUser(userEntity);
         System.out.println("insert成功");
    }

    @RequestMapping("/deleteUser")
    public void deleteUser(int id){
        userService.deleteUser(id);
        System.out.println("delete成功");
    }

    @PostMapping("/updateUser")
    public void updateUser(@RequestBody UserEntity userEntity){
        userService.updateUser(userEntity);
        System.out.println("update成功");
    }




}

8、在resource文件夹下新建mapper文件夹并新建映射Usermapper.xml文件在里面写相应的数据库操作语句

<?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.bys.mapper.UserMapper">


    <select id="selectAllUser" resultType="com.example.bys.entity.UserEntity">
        select * from user
    </select>

    <select id="selectOneUser" resultType="com.example.bys.entity.UserEntity">
        select * from user where userid = #{id}
    </select>

    <insert id="insertUser" parameterType="com.example.bys.entity.UserEntity">
        insert into user (username,password,email) values (#{username},#{password},#{email})
    </insert>

    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from user where userid = #{id}
    </delete>

    <update id="updateUser" parameterType="com.example.bys.entity.UserEntity">
        update user set username=#{username},password=#{password},email=#{email} where userid=#{userid}
    </update>


</mapper>

9、最后在启动类中加上一句扫描mapper包的位置然后直接run起来就好了

@MapperScan("com.example.bys.mapper")  //扫描mapper包

10、好啦到这里已经基本完成啦。。。下面用postman测试工具来测试（蛮好用的工具大家可以下载一个来玩一下）

测试查找全部用户注意路径和Usercontroller里面的要一致

测试查找单个用户

测试新增用户

测试删除用户

测试修改用户

工程代码已上传至Github 大家自行下载吧。。。。。。。

https://github.com/Goodnamelzw/springboot-mybatis

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标签：springboot,void,改查,UserEntity,id,mybatis,import,password,public
来源： https://blog.csdn.net/sm16111/article/details/104159281