springboot+mybatis实现数据增删改查

本是古典何须时尚 2023-07-03 06:27 73阅读 0赞

## 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**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70][]

**2、pom.xml文件 加入依赖mysql 等等**

<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**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 1][]

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**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 2][]

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

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 3][]

**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）**

![20200204105529187.png][]

**测试查找全部用户 注意路径和Usercontroller里面的要一致**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 4][]

**测试查找单个用户  **![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 5][]

**测试新增用户**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 6][]![20200204105944502.png][]

**测试删除用户**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 7][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 8][]

**测试修改用户**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NtMTYxMTE_size_16_color_FFFFFF_t_70 9][]![20200204110237342.png][]

工程代码已上传至Github 大家自行下载吧。。。。。。。

[https://github.com/Goodnamelzw/springboot-mybatis][https_github.com_Goodnamelzw_springboot-mybatis]

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[20200204105529187.png]: https://img-blog.csdnimg.cn/20200204105529187.png
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[20200204105944502.png]: https://img-blog.csdnimg.cn/20200204105944502.png
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[20200204110237342.png]: https://img-blog.csdnimg.cn/20200204110237342.png
[https_github.com_Goodnamelzw_springboot-mybatis]: https://github.com/Goodnamelzw/springboot-mybatis