SpringBoot之整合MyBatis實(shí)現(xiàn)CRUD方式

更新時(shí)間：2023年08月14日 16:50:06 作者：君君要上天

這篇文章主要介紹了SpringBoot之整合MyBatis實(shí)現(xiàn)CRUD方式,具有很好的參考價(jià)值,希望對(duì)大家有所幫助,如有錯(cuò)誤或未考慮完全的地方,望不吝賜教

SpringBoot整合MyBatis實(shí)現(xiàn)CRUD

SpringBoot項(xiàng)目的持久層一般都是使用JPA或者M(jìn)yBatis，我個(gè)人是比較喜歡MyBatis。

首先我們打開pom.xml

添加上mybatis需要的一些依賴

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.3.1</version>
</dependency>
<dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>0.9.5.2</version>
</dependency>

在resources下創(chuàng)建mybatis-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <!-- 獲取數(shù)據(jù)庫自增id -->
        <setting name="useGeneratedKeys" value="true"/>
        <!-- 支持別名 -->
        <setting name="useColumnLabel" value="true" />
        <!-- 支持駝峰命名轉(zhuǎn)換，例如表字段create_time 對(duì)應(yīng)實(shí)體類的createTime屬性 -->
        <setting name="mapUnderscoreToCamelCase" value="true" />
    </settings>
</configuration>

建表

CREATE TABLE `t_user` (
  `user_id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) DEFAULT '' COMMENT '用戶名',
  `create_time` datetime DEFAULT NULL COMMENT '創(chuàng)建時(shí)間',
  `update_time` datetime DEFAULT NULL COMMENT '修改時(shí)間',
  PRIMARY KEY (`user_id`)
) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

創(chuàng)建對(duì)應(yīng)的實(shí)體類

package com.example.demo.entity;
import java.util.Date;
public class User {
    private Integer userId;
    private String username;
    private Date createTime;
    private Date updateTime;
    public Integer getUserId() {
        return userId;
    }
    public void setUserId(Integer userId) {
        this.userId = userId;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public Date getCreateTime() {
        return createTime;
    }
    public void setCreateTime(Date createTime) {
        this.createTime = createTime;
    }
    public Date getUpdateTime() {
        return updateTime;
    }
    public void setUpdateTime(Date updateTime) {
        this.updateTime = updateTime;
    }
}

創(chuàng)建Dao

package com.example.demo.dao;
import com.example.demo.entity.User;
import java.util.List;
public interface UserDao {
    List<User> getAll();
    User find(int userId);
    int insert(User user);
    int delete(int userId);
}

resources目錄下創(chuàng)建mybatis目錄，用于存放mapper文件

整體目錄結(jié)構(gòu)如下

這里寫圖片描述

在application.yml配置文件中配置數(shù)據(jù)庫連接信息和mybatis

spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true
    username: root
    password: root
mybatis:
  config-location: classpath:mybatis-config.xml
  mapper-locations: classpath:mybatis/*Mapper.xml

編寫UserMapper.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.demo.dao.UserDao">
    <select id="getAll" resultType="com.example.demo.entity.User">
        select * from t_user order by user_id desc
    </select>
    <select id="find" resultType="com.example.demo.entity.User">
        select * from t_user where user_id = #{userId}
    </select>
    <insert id="insert" useGeneratedKeys="true" keyProperty="userId" keyColumn="user_id" parameterType="com.example.demo.entity.User">
        insert into t_user(username,create_time,update_time) values(#{username},#{createTime},#{updateTime})
    </insert>
    <update id="update" parameterType="com.example.demo.entity.User">
       update t_user
       <set>
           <if test="username != null">username=#{username},</if>
           <if test="updateTime != null">update_time=#{updateTime},</if>
       </set>
        where user_id=#{userId}
    </update>
    <delete id="delete">
        delete from t_user where user_id=#{userId}
    </delete>
</mapper>

修改SpringBoot啟動(dòng)類，加上 @MapperScan 注解

package com.example.demo;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("com.example.demo.dao")
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

下面進(jìn)行測(cè)試，打開UserDao，點(diǎn)擊接口名UserDao，然后按alt+回車，點(diǎn)擊create test：

這里寫圖片描述

選中userdao中要進(jìn)行測(cè)試的方法

這里寫圖片描述

選擇確定，然后會(huì)自動(dòng)創(chuàng)建UserDaoTest，編寫測(cè)試方法然后右鍵，點(diǎn)擊run執(zhí)行測(cè)試方法

package com.example.demo.dao;
import com.example.demo.entity.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import java.util.Date;
import java.util.List;
import static org.junit.Assert.*;
@RunWith(SpringRunner.class)
@SpringBootTest
public class UserDaoTest {
    @Autowired
    private UserDao userDao;
    @Test
    public void getAll() {
        List<User> list = userDao.getAll();
        assertEquals(1,list.size());
    }
    @Test
    public void find() {
        User user = userDao.find(1);
        assertEquals("tom",user.getUsername());
    }
    @Test
    public void insert() {
        User user = new User();
        user.setUsername("jack");
        user.setCreateTime(new Date());
        int num = userDao.insert(user);
        assertEquals(1,num);
    }
    @Test
    public void delete() {
        int num = userDao.delete(1);
        assertEquals(1,num);
    }
}

注意：

要給測(cè)試類加上@RunWith 和 @SpringBootTest 注解
如果你用的是IDEA，那么在Autowired UserDao時(shí)，可能會(huì)提示錯(cuò)誤，原因是找不到對(duì)應(yīng)的bean。
UserDao是接口，找不到bean是正常的，可以不用管這個(gè)錯(cuò)誤，運(yùn)行時(shí)是不會(huì)報(bào)錯(cuò)的。
如果你想把錯(cuò)誤提示去掉，可以在setting設(shè)置中錯(cuò)誤級(jí)別從Error改為Warning，具體見下圖：

這里寫圖片描述