1、願景
為簡化開發而生,Mybatis的好搭檔。
2、特性
- 無侵入:隻做增強不做改變,不會對現有工程産生影響
- 損耗小:啟動即會自動注入基本 CURD,性能基本無損耗,直接面向對象操作
- 強大的 CRUD 操作:内置通用 Mapper、 Service,通過少量配置即可實作單表大部分 CRUD 操作
- 支援 Lambda 形式調用:通過 Lambda 表達式,友善的編寫各類查詢條件,無需再擔心字段寫錯
- 支援主鍵自動生成:支援多達 4 種主鍵政策(内含分布式唯一 ID 生成器 - Sequence)
- 支援 ActiveRecord 模式:實體類隻需繼承 Model 類即可進行強大的 CRUD 操作
- 支援自定義全局通用操作:支援全局通用方法注入( Write once, use anywhere )
- 内置代碼生成器:采用代碼或 Maven 插件快速生成 Mapper 、 Model 、 Service 、 Controller 代碼
- 内置分頁插件
- 分頁插件支援多種資料庫
- 内置性能分析插件:可輸出 Sql 語句以及其執行時間,能快速揪出慢查詢
- 内置全局攔截插件:全表 delete 、 update 操作智能分析阻斷,也可自定義攔截規則,預防誤操作
3、快速入門
環境:idea+gradle+springboot+mybatis-plus+mysql+jdk1.8
工程:建立一個gradle建構的空的 Spring Boot 工程
(1)依賴
- build.gradle檔案
plugins {
id 'org.springframework.boot' version '2.5.2'
id 'io.spring.dependency-management' version '1.0.11.RELEASE'
id 'java'
id 'war'
}
ext {
mybatisplusVersion = '3.4.2'
swaggerFoxVersion = '2.9.2'
swaggerCoreVersion = '1.5.24'
postGisJdbcVersion = '2.5.0'
druidVersion = '1.1.9'
hutoolVersion = '5.3.8'
aspectVersion = '1.8.10'
easyExcelVersion = '2.2.6'
}
group = 'com.mybatisplus'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
configurations {
compileOnly {
extendsFrom annotationProcessor
}
}
repositories {
mavenCentral()
}
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.mybatis.spring.boot:mybatis-spring-boot-starter:2.2.0'
compileOnly 'org.projectlombok:lombok'
annotationProcessor 'org.projectlombok:lombok'
/* MyBatis-Plus */
implementation("com.baomidou:mybatis-plus-boot-starter:${mybatisplusVersion}")
/* Druid 連接配接池 */
implementation("com.alibaba:druid-spring-boot-starter:${druidVersion}")
/* PostgreSQL */
implementation 'org.postgresql:postgresql:9.4.1212.jre7'
/* PostGis-Jdbc */
implementation("net.postgis:postgis-jdbc:${postGisJdbcVersion}")
compile 'com.alibaba:druid:1.0.27'
compile group: 'org.springframework.boot', name: 'spring-boot-starter-log4j2', version: '1.4.0.RELEASE'
implementation 'junit:junit:4.12'
// 排除沖突
configurations {
mybatisGenerator
compile.exclude module: 'spring-boot-starter-logging'
}
}
test {
useJUnitPlatform()
}
(2)配置
- application.yml 配置檔案中添加資料庫的相關配置
server:
port: 9080
spring:
datasource:
driver-class-name: org.postgis.DriverWrapper
url: jdbc:postgresql_postGIS://****:*/BOOK?useUnicode=true&characterEncoding=UTF-8
username: ****
password: ****
# ??druid???
type: com.alibaba.druid.pool.DruidDataSource
filters: stat
maxActive: 20
initialSize: 1
maxWait: 60000
minIdle: 1
timeBetweenEvictionRunsMillis: 60000
minEvictableIdleTimeMillis: 300000
validationQuery: select 'x'
testWhileIdle: true
testOnBorrow: false
testOnReturn: false
poolPreparedStatements: true
maxOpenPreparedStatements: 20
(3)在 Spring Boot 啟動類中添加 @MapperScan 注解,掃描 Mapper 檔案夾
@SpringBootApplication
@MapperScan("com.mybatisplus.mapper")
public class MybatisplusApplication {
public static void main(String[] args) {
SpringApplication.run(MybatisplusApplication.class, args);
}
}
(4)編碼
- 實體類:Users.java
package com.mybatisplus.entity;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Users {
private int id;
private String name;
private int age;
private String email;
}
- Controller層:UserController.java
package com.mybatisplus.controller;
import com.mybatisplus.entity.Users;
import com.mybatisplus.mapper.UserMapper;
import lombok.RequiredArgsConstructor;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
@RequiredArgsConstructor
public class UserController {
private final UserMapper userMapper;
//查詢清單
@GetMapping("/queryallusers")
public List<Users> book() {
List<Users> userList = userMapper.selectList(null);
return userList;
}
}
- DAO層:
UserMapper extends BaseMapper <Users>
package com.mybatisplus.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.mybatisplus.entity.Users;
import org.apache.ibatis.annotations.Mapper;
@Mapper
public interface UserMapper extends BaseMapper<Users> {
}
(5)資料庫
![](https://img.laitimes.com/img/9ZDMuAjOiMmIsIjOiQnIsIyZuBnLyUzM2EzMwcTM3EzNwEjMwIzLc52YucWbp5GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.png)
4、Service層
對于service層可選擇行要與不要,如果沒有業務邏輯處理可以不要,如果需要service層,實體類與Dao層保持不變,其他具體如下:
(1)controller層
- UserController.java
package com.mybatisplus.controller;
import com.mybatisplus.entity.Users;
import com.mybatisplus.service.UsersService;
import lombok.RequiredArgsConstructor;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
@RequiredArgsConstructor
public class UserController {
private final UsersService usersService;
//查詢清單
@GetMapping("/queryallusers")
public List<Users> book() {
List<Users> userList = usersService.list();
return userList;
}
}
(2)service層
- UsersService.java
package com.mybatisplus.service;
import com.baomidou.mybatisplus.extension.service.IService;
import com.mybatisplus.entity.Users;
public interface UsersService extends IService<Users> {
}
- UsersServiceImpl.java
package com.mybatisplus.service;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.mybatisplus.entity.Users;
import com.mybatisplus.mapper.UserMapper;
import org.springframework.stereotype.Service;
@Service
public class UsersServiceImpl extends ServiceImpl<UserMapper, Users> implements UsersService {
}
5、執行結果
通路:
http://localhost:9080/queryallusers
結果: