Mybatis-plus插件的学习与使用

本文是基于Windows 10系统环境，利用mybatis-plus实现数据库表的CRUD

Windows 10
IntelliJ

一、构建过程（简单入门）

(1) 打开IntelliJ，创建一个新项目

(2) 选择“maven”工程，然后点击“next”

(3) 填写公司ID等信息，然后点击“next”

(4) 填写项目名称等信息，然后点击“finish”

(5) 点击“pom.xml”文件，然后填写各种依赖的坐标

<code>
<project>         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelversion>4.0.0/<modelversion>

    <parent>
        <groupid>org.springframework.boot/<groupid>
        <artifactid>spring-boot-starter-parent/<artifactid>
        <version>2.1.4.RELEASE/<version>
    /<parent>

    <groupid>com.inspur.intellid/<groupid>
    <artifactid>mybatis-plus-demo/<artifactid>
    <version>1.0-SNAPSHOT/<version>

    <dependencies>
        <dependency>
            <groupid>org.springframework.boot/<groupid>
            <artifactid>spring-boot-starter/<artifactid>
            <exclusions>
                <exclusion>
                    <groupid>org.springframework.boot/<groupid>
                    <artifactid>spring-boot-starter-logging/<artifactid>
                /<exclusion>
            /<exclusions>
        /<dependency>
        <dependency>
            <groupid>org.springframework.boot/<groupid>
            <artifactid>spring-boot-starter-test/<artifactid>
\t\t\t<scope>test/<scope>
        /<dependency>
        
        <dependency>
            <groupid>com.baomidou/<groupid>
            <artifactid>mybatis-plus-boot-starter/<artifactid>
            <version>3.1.1/<version>
        /<dependency>
        
        <dependency>
            <groupid>mysql/<groupid>
            <artifactid>mysql-connector-java/<artifactid> 

            <version>5.1.47/<version>
        /<dependency>
        <dependency>
            <groupid>org.projectlombok/<groupid>
            <artifactid>lombok/<artifactid>
            <optional>true/<optional>
        /<dependency>
    /<dependencies>

    <build>
        <plugins>
            <plugin>
                <groupid>org.springframework.boot/<groupid>
                <artifactid>spring-boot-maven-plugin/<artifactid>
            /<plugin>
        /<plugins>
    /<build>
/<project>/<code>

(6) 创建一个User类，然后生成相应的属性和方法

<code>package com.inspur.intellid.mybatisplus.pojo;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("user")
public class User { 

    private String id;
    private String username;
    private String nickname;
    private String type;
    private String password;

}/<code>

(7) 创建一个UserMapper类

<code>package com.inspur.intellid.mybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.inspur.intellid.mybatisplus.pojo.User;
import org.apache.ibatis.annotations.Mapper;

@Mapper 

public interface UserMapper extends BaseMapper<user> {
}/<user>/<code>

(8) 创建一个MybatisPlusApplication启动类

<code>package com.inspur.intellid.mybatisplus;

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

@MapperScan("com.inspur.intellid.mybatisplus.mapper")
@SpringBootApplication
public class MybatisPlusApplication {
    public static void main(String[] args) {
        SpringApplication.run(MybatisPlusApplication.class, args);
    } 

}/<code>

(9) 创建一个主配置文件Application.properties

(10) 创建一个UserMapper类

<code>package com.inspur.intellid.mybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.inspur.intellid.mybatisplus.pojo.User;
import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface UserMapper extends BaseMapper<user> {
}
/<user>/<code>

(11) 写一个测试类，测试CRUD结果

<code>
package com.inspur.intellid.mybatisplus.mapper;

import com.inspur.intellid.mybatisplus.pojo.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.SpringJUnit4ClassRunner;

import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
public class UserMapperTest {
    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelect(){
        List<user> users = this.userMapper.selectList(null);
        for(User user : users){
            System.out.println(user);
        }
    }
}/<user>/<code>