Mybatis-Plus 在springboot中的使用

首先是項目結構

pom文件：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://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>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.gbx</groupId>
    <artifactId>mp-demo01</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mp-demo01</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <!--mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.0.5</version>
        </dependency>

        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.13</version>
        </dependency>
        <!--lombok用來簡化實體類-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

application.properties文件：

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=black123

server.port=8080

spring.profiles.active=dev


#mybatis日誌
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
#全局設置主鍵生成策略
mybatis-plus.global-config.db-config.id-type=auto

#設置邏輯刪除對應值（此處 1 爲刪除，可以使用默認）
mybatis-plus.global-config.db-config.logic-delete-value=1
mybatis-plus.global-config.db-config.logic-not-delete-value=0

實體類 entity：

BaseEntity：

package com.gbx.mpdemo01.entity;

import com.baomidou.mybatisplus.annotation.FieldFill;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableLogic;
import com.baomidou.mybatisplus.annotation.Version;
import lombok.Data;

import java.util.Date;

@Data
public class BaseEntity {
    @TableField(fill = FieldFill.INSERT)
    private Date createTime;

    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Date updateTime;

    @Version //樂觀鎖
    @TableField(fill = FieldFill.INSERT)
    private Integer version;

    @TableLogic //邏輯刪除字段設定
    @TableField(fill = FieldFill.INSERT)
    private Integer deleted;
}

UserEntity：

package com.gbx.mpdemo01.entity;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import lombok.Data;

@Data
public class User extends BaseEntity{
    @TableId(type = IdType.ID_WORKER)
    //@TableId(type = IdType.ID_WORKER_STR) 字符串類型自增長
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

mapper接口集成BaseMapper<T> 就可以了，泛型選擇自己的entity類型：

package com.gbx.mpdemo01.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.gbx.mpdemo01.entity.User;

public interface UserMapper extends BaseMapper<User> {
}

配置handler：

package com.gbx.mpdemo01.handler;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.util.Date;

@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
    @Override
    public void insertFill(MetaObject metaObject) {
        this.setFieldValByName("createTime",new Date(),metaObject);
        this.setFieldValByName("updateTime",new Date(),metaObject);
        this.setFieldValByName("version",1,metaObject);//樂觀鎖初始化
        this.setFieldValByName("deleted",0,metaObject);//邏輯刪除初始化
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        this.setFieldValByName("updateTime",new Date(),metaObject);
    }
}

添加配置類：

package com.gbx.mpdemo01.config;

import com.baomidou.mybatisplus.core.injector.ISqlInjector;
import com.baomidou.mybatisplus.extension.injector.LogicSqlInjector;
import com.baomidou.mybatisplus.extension.plugins.OptimisticLockerInterceptor;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.plugins.PerformanceInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;

@Configuration
@MapperScan("com.gbx.mpdemo01.mapper") //也可以放置在啓動類上
public class MpConfig {

    /**
     * 樂觀鎖插件配置
     */
    @Bean
    public OptimisticLockerInterceptor optimisticLockerInterceptor() {
        return new OptimisticLockerInterceptor();
    }

    /**
     * 分頁插件
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        return new PaginationInterceptor();
    }

    /**
     * 邏輯刪除插件
     */
    @Bean
    public ISqlInjector sqlInjector() {
        return new LogicSqlInjector();
    }

    /**
     * SQL 執行性能分析插件
     * 開發環境使用，線上不推薦。 maxTime 指的是 sql 最大執行時長
     */
    @Bean
    @Profile({"dev","test"})// 設置 dev test 環境開啓
    public PerformanceInterceptor performanceInterceptor() {
        PerformanceInterceptor performanceInterceptor = new PerformanceInterceptor();
        performanceInterceptor.setMaxTime(200);//ms，超過此處設置的ms則sql不執行
        performanceInterceptor.setFormat(true);
        return performanceInterceptor;
    }
}

啓動類：

package com.gbx.mpdemo01;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MpDemo01Application {

    public static void main(String[] args) {
        SpringApplication.run(MpDemo01Application.class, args);
    }

}

測試類：

package com.gbx.mpdemo01;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.gbx.mpdemo01.entity.User;
import com.gbx.mpdemo01.mapper.UserMapper;
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.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@RunWith(SpringRunner.class)
@SpringBootTest
public class MpDemo01ApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void findAll() {
        List<User> userList = userMapper.selectList(null);
        System.out.println(userList);
    }

    @Test
    public void addUser(){
        User user = new User();
        user.setName("yule");
        user.setAge(30);
        user.setEmail("[email protected]");

        int insert = userMapper.insert(user);
        System.out.println("insert:"+ insert);
    }

    @Test
    public void updateUser(){
        User user = new User();
        user.setId(1258250492107075585L);
        user.setAge(120);
        int row = userMapper.updateById(user);

        System.out.println("row:"+ row + ",user:"+ user);
    }

    @Test
    public void testOptimisticLock(){
        User user = userMapper.selectById(1258272800230092802L);
        user.setAge(666);
        int row = userMapper.updateById(user);
        System.out.println("row:"+ row + ",user:"+ user);
    }

    @Test
    public void findById(){
        User user = userMapper.selectById(1l);
        System.out.println(user);
    }

    @Test
    public void findByIdList(){
        List<User> userList = userMapper.selectBatchIds(Arrays.asList(1l, 2L, 3L));
        userList.forEach(System.out::println);
    }

    @Test
    public void findByMap(){
        Map<String,Object> map = new HashMap<>();
        map.put("name","石光榮");
        map.put("age",46);
        List<User> userList = userMapper.selectByMap(map);

        userList.forEach(System.out::println);
    }

    @Test
    public void findByPage(){
        Page<User> userPage = new Page<>(1,3);
        userMapper.selectPage(userPage,null);

        userPage.getRecords().forEach(System.out::println);
        System.out.println("currentPage:" + userPage.getCurrent());
        System.out.println("size:" + userPage.getSize());
        System.out.println("total:" + userPage.getTotal());
        System.out.println("pages:" + userPage.getPages());

        System.out.println(userPage.hasNext());
        System.out.println(userPage.hasPrevious());
    }

    @Test
    public void deleteById(){
        int result = userMapper.deleteById(1258285643637731329l);
        System.out.println(result);
    }

    @Test
    public void findByWrapper(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();

        //ge,gt,le,lt
        queryWrapper.ge("age",20);
        //select
        queryWrapper.select("id","name");

        List<User> userList = userMapper.selectList(queryWrapper);
        
        userList.forEach(System.out::println);
    }

}

擴展（可以下載爲知筆記版wrapper，已共享，詳見資源鏈接）：