源碼下載
原文鏈接

一、MyBatis-Plus介紹

Mybatis-Plus是一個(gè)Mybatis框架的增強(qiáng)插件,根據(jù)官方描述,plus只做增強(qiáng)不做改變,引入它不會(huì)對(duì)現(xiàn)有mybatis工程產(chǎn)生任何影響，并且只需簡(jiǎn)單配置,即可快速進(jìn)行 CURD 操作,從而節(jié)省大量時(shí)間.代碼自動(dòng)生成,分頁(yè),從代碼結(jié)構(gòu)上更簡(jiǎn)潔、開(kāi)發(fā)效率更高了

二、開(kāi)始創(chuàng)建quick-mybatis-plus工程，pom依賴如下

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.4.RELEASE</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>quick-mybatis-plus</artifactId>


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

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.11</version>
        </dependency>

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.2.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.6</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.4</version>
        </dependency>

    </dependencies>
</project>

application.yml配置如下

# 配置端口
server:
  port: 8088
spring:
  # 配置數(shù)據(jù)源
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8
    username: root
    password: root
    type: com.alibaba.druid.pool.DruidDataSource
# mybatis-plus相關(guān)配置
mybatis-plus:
  # xml掃描，多個(gè)目錄用逗號(hào)或者分號(hào)分隔（告訴 Mapper 所對(duì)應(yīng)的 XML 文件位置）
  mapper-locations: classpath:mapper/*.xml
  # 以下配置均有默認(rèn)值,可以不設(shè)置
  global-config:
    db-config:
      #主鍵類型  auto:"數(shù)據(jù)庫(kù)ID自增" 1:"用戶輸入ID",2:"全局唯一ID (數(shù)字類型唯一ID)", 3:"全局唯一ID UUID";
      id-type: auto
      #字段策略 IGNORED:"忽略判斷"  NOT_NULL:"非 NULL 判斷")  NOT_EMPTY:"非空判斷"
      field-strategy: NOT_EMPTY
      #數(shù)據(jù)庫(kù)類型
      db-type: MYSQL
  configuration:
    # 是否開(kāi)啟自動(dòng)駝峰命名規(guī)則映射:從數(shù)據(jù)庫(kù)列名到Java屬性駝峰命名的類似映射
    map-underscore-to-camel-case: true
    # 如果查詢結(jié)果中包含空值的列，則 MyBatis 在映射的時(shí)候，不會(huì)映射這個(gè)字段
    call-setters-on-nulls: true
    # 這個(gè)配置會(huì)將執(zhí)行的sql打印出來(lái)，在開(kāi)發(fā)或測(cè)試的時(shí)候可以用
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

表結(jié)構(gòu)

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(64) DEFAULT NULL COMMENT '姓名',
  `email` varchar(64) DEFAULT NULL COMMENT '郵箱',
  PRIMARY KEY (`id`),
  UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC

數(shù)據(jù)準(zhǔn)備

insert into `test`.`user` ( `id`, `name`, `email`) values ( '1', 'bx1', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '2', 'zhangsan', 'zan@qq.com');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '3', 'xxxx', 'aaaaa');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '5', '小白菜', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '6', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '7', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '8', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '9', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '10', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '11', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '12', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '13', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '14', 'hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '15', '嗷嗷hello', 'xxxzcxz');
insert into `test`.`user` ( `id`, `name`, `email`) values ( '16', '小蘿卜', '生生世世');

三、代碼編寫(xiě)

3.1、啟動(dòng)類代碼

package com.lxd.mybatisplus;

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

/**
* @author liuxiaoding
* @Date 2019/11/19
**/
@SpringBootApplication
@MapperScan(basePackages = {"com.lxd.mybatisplus.mapper"})
public class Application {
   public static void main(String[] args) {
       SpringApplication.run(Application.class,args);
   }
}

3.2、編寫(xiě)實(shí)體類和mapper
User.java

package com.lxd.mybatisplus.entity;

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

/**
* @author liuxiaoding
* @Date 2019/11/19
**/
@Data
@TableName("user")//@TableName中的值對(duì)應(yīng)著表名稱
public class User {
   /**
    * 主鍵
    * @TableId中可以決定主鍵的類型,不寫(xiě)會(huì)采取默認(rèn)值,默認(rèn)值可以在yml中配置
    * AUTO: 數(shù)據(jù)庫(kù)ID自增
    * INPUT: 用戶輸入ID
    * ID_WORKER: 全局唯一ID，Long類型的主鍵
    * ID_WORKER_STR: 字符串全局唯一ID
    * UUID: 全局唯一ID，UUID類型的主鍵
    * NONE: 該類型為未設(shè)置主鍵類型
    */

   @TableId(type = IdType.AUTO)
   private Integer id;

   /**
    * 姓名
    */
   private String name;

   /**
    * 郵箱
    */
   private String email;
}

User.mapper

package com.lxd.mybatisplus.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.lxd.mybatisplus.entity.User;

/**
* @author liuxiaoding
* @Date 2019/11/19
**/
public interface UserMapper extends BaseMapper<User> {
}

UserService.java

  package com.lxd.mybatisplus.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.lxd.mybatisplus.entity.User;

/**
* @author liuxiaoding
* @Date 2019/11/19
**/
public interface UserService extends IService<User> {

}

  ```
  
實(shí)現(xiàn)類  UserServiceImpl.java

package com.lxd.mybatisplus.service;

import com.baomidou.mybatisplus.extension.service.IService;
import com.lxd.mybatisplus.entity.User;

/**

• @author liuxiaoding
• @Date 2019/11/19
  **/
  public interface UserService extends IService<User> {

}

3.3、編寫(xiě)mybatis配置類

package com.lxd.mybatisplus.config;

import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**

• MybatisPlus配置類

• @author liuxiaoding

• @Date 2019/11/19
  /
  @Configuration
  public class MybatisPlusConfig {
  /

  • 注意在3.2版本，mp的sql性能分析插件PerformanceInterceptor已經(jīng)被刪除了，我們可以選擇其他工具來(lái)實(shí)現(xiàn)
    */

  /**

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

}

  
# 四、mybatis-plush基礎(chǔ)curd功能演示
在上面的示例代碼中我們可以看到,service和mapper中我們沒(méi)有寫(xiě)任何方法,MyBatis-Plus官方封裝了許多基本CRUD的方法,可以直接使用來(lái)大量節(jié)約時(shí)間,MP共通方法詳見(jiàn)IService,ServiceImpl,BaseMapper源碼,寫(xiě)入操作在ServiceImpl中已有事務(wù)綁定,這里我們舉一些常用的方法演示.如下
UserInfoController

package com.lxd.mybatisplus.controller;

import com.lxd.mybatisplus.entity.User;
import com.lxd.mybatisplus.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**

• @author liuxiaoding

• @Date 2019/11/19
  **/
  @RestController
  @RequestMapping(value = "user")
  public class UserController {
  @Autowired
  private UserService userService;

  /**

  • 批量獲取用戶
  • @return
    */
    @RequestMapping("/getList")
    public List<User> getList(){
    List<User> userInfoEntityList = userService.list();
    return userInfoEntityList;
    }

  /**

  • 根據(jù)id獲取用戶信息
  • @param userId
  • @return
    */
    @RequestMapping("/getUser")
    public User getUser(Integer userId){
    return userService.getById(userId);
    }

  /**

  • 添加用戶返回主鍵
  • @param user
  • @return
    */
    @RequestMapping("/addUser")
    public String addUser(User user){
    userService.save(user);
    return "主鍵id："+user.getId();
    }

  /**

  • 刪除
  • @param userId
  • @return
    */
    @RequestMapping("/delete")
    public boolean delete(Integer userId){
    return userService.removeById(userId);
    }

  /**

  • 根據(jù)id更新
  • @param user
  • @return
    */
    @RequestMapping(value = "update")
    public boolean update(User user){
    return userService.updateById(user);
    }
    }