SpringBoot整合MybatisPlus

1. SpringBoot整合MybatisPlus

1.1 准备数据库脚本

CREATE TABLE If Not Exists user
(
    id BIGINT(20) NOT NULL COMMENT '主键ID',
    name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
    age INT(11) NULL DEFAULT NULL COMMENT '年龄',
    email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',
    PRIMARY KEY (id)
);



replace into user (id,name, age, email) VALUES
(1, 'Jone', 18, 'test1@mszlu.com'),
(2, 'Jack', 20, 'test2@mszlu.com'),
(3, 'Tom', 28, 'test3@mszlu.com'),
(4, 'Sandy', 21, 'test4@mszlu.com'),
(5, 'Billie', 24, 'test5@mszlu.com');

1.2 新建SpringBoot工程

1.2.1 依赖

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.mszlu</groupId>
    <artifactId>union</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.0</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.3</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
         <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
</project>

1.2.2配置

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&serverTimeZone=UTC
#数据库 默认采用的数据源HikariDataSource

#sql脚本初始化 2.5.0
#DataSourceInitializationConfiguration 源码中得知不能写username和password，但好多文档说要写
#spring.sql.init.username=root
#spring.sql.init.password=root
spring.sql.init.schema-locations=classpath*:sql/*.sql
spring.sql.init.data-locations=classpath*:sql/data/*.sql

1.2.3 启动测试

package com.mszlu.union;

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

@SpringBootApplication
public class App {

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

1.3 MybatisPlus

1.3.1 Mapper接口

package com.mszlu.union.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.mszlu.union.pojo.User;

public interface UserMapper extends BaseMapper<User> {
}

package com.mszlu.union.config;

import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@MapperScan("com.mszlu.union.mapper")
public class MybatisPlusConfig {

    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor(){
        MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
        mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor());
        return mybatisPlusInterceptor;
    }
}

1.3.2 Service代码

package com.mszlu.union.service;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.conditions.query.LambdaQueryChainWrapper;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.mszlu.union.mapper.UserMapper;
import com.mszlu.union.pojo.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
@Slf4j
public class UserService {

    @Autowired
    private UserMapper userMapper;

    public List<User> findAll(){

        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();

        List<User> users = userMapper.selectList(queryWrapper);
        return users;
    }
	//分页
    public List<User> findPage(){

        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();
        Page page = new Page(2,2);
        Page<User> userPage = userMapper.selectPage(page,queryWrapper);
        log.info("total:{}",userPage.getTotal());
        log.info("pages:{}",userPage.getPages());
        return userPage.getRecords();
    }
}

1.3.3 测试

package com.mszlu.union.controller;

import com.mszlu.union.pojo.User;
import com.mszlu.union.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("user")
public class UserController {

    @Autowired
    private UserService userService;

    @GetMapping("findAll")
    public List<User> findAll(){
        return userService.findAll();
    }
    @GetMapping("findPage")
    public List<User> findPage(){
        return userService.findPage();
    }
}