How SpringBoot integrates mybatis+mybatis-plus

Preparation work

1. Prepare the following data table

CREATE TABLE `student` (
  `id` varchar(32) NOT NULL,
  `gender` varchar(32) DEFAULT NULL,
  `age` int(12) DEFAULT NULL,
  `nick_name` varchar(32) DEFAULT NULL,
  `name` varchar(32) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2. Insert several pieces of test data

Integration steps

The complete package structure of the project is shown in the figure

1. Import maven dependencies

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <mysql-connector-java.version>8.0.11</mysql-connector-java.version>
        <commons-lang3.version>3.7</commons-lang3.version>
        <fastjson.version>1.2.47</fastjson.version>
        <mybatis-plus-boot-starter.version>3.3.0</mybatis-plus-boot-starter.version>
        <mybatis-plus-generator.version>3.3.0</mybatis-plus-generator.version>
        <druid.version>1.1.14</druid.version>
        <lombok.version>1.18.0</lombok.version>
        <dubbo-spring-boot-starter.version>2.0.0</dubbo-spring-boot-starter.version>
        <swagger.version>2.9.2</swagger.version>
        <swagger-bootstrap-ui.version>1.9.6</swagger-bootstrap-ui.version>
    </properties>
 
    <dependencies>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.4</version>
        </dependency>
 
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
 
        <!--mysql依赖-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql-connector-java.version}</version>
        </dependency>
 
        <!--阿里巴巴fastjosn依赖-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>${fastjson.version}</version>
        </dependency>
 
        <!--阿里巴巴数据库连接池依赖-->
        <!-- Druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>${druid.version}</version>
        </dependency>
 
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>
 
        <!-- MyBatis增强工具-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatis-plus-boot-starter.version}</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-generator</artifactId>
            <version>${mybatis-plus-generator.version}</version>
        </dependency>
 
        <!-- lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>${lombok.version}</version>
        </dependency>
 
        <!--swagger-ui-->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>${swagger.version}</version>
        </dependency>
 
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>${swagger.version}</version>
        </dependency>
 
        <dependency>
            <groupId>com.github.xiaoymin</groupId>
            <artifactId>swagger-bootstrap-ui</artifactId>
            <version>${swagger-bootstrap-ui.version}</version>
        </dependency>
 
    </dependencies>

2. Configuration file application.yml

server:
  port: 8083
logging:
  config: classpath:logback-spring.xml  #日志
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://IP:3306/school?autoReconnect=true&useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false
    username: root
    password: root
    druid:
      max-active: 100
      initial-size: 10
      max-wait: 60000
      min-idle: 5
  #设置单个文件最大上传大小
  servlet:
    multipart:
      max-file-size: 20MB
mybatis-plus:
  mapper-locations: classpath*:mapper/*.xml
  global-config:
    db-column-underline: true  #开启驼峰转换
    db-config:
      id-type: uuid
      field-strategy: not_null
    refresh: true
  configuration:
    map-underscore-to-camel-case: true
    #log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #打印sql语句便于调试

3. In order to facilitate the debugging interface later, add a swagger configuration

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
 
/**
 * swagger文档，项目启动后，浏览器访问:http://localhost:8083/swagger-ui.html
 */
@Configuration
@EnableSwagger2
public class ApiSwagger2 {
 
    @Bean
    public Docket createRestBmbsApi() {
        return new Docket(DocumentationType.SWAGGER_2)
                .groupName("users")
                .apiInfo(apiInfo())
                .select()
                .apis(RequestHandlerSelectors.basePackage("com.congge.controller"))
                .paths(PathSelectors.any())
                .build();
    }
 
    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()
                .title("后端相关API")
                .version("1.0")
                .build();
    }
 
}

4. Entity class

import com.baomidou.mybatisplus.annotation.TableField;
import lombok.Data;
 
@Data
public class Student {
 
    @TableField("id")
    private String id;
 
    @TableField("name")
    private String name;
 
    @TableField("gender")
    private String gender;
 
    @TableField("age")
    private int age;
 
    @TableField("nick_name")
    private String nickName;
 
}

5. Dao interface, add a method to query all data

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.congge.entity.Student;
import org.apache.ibatis.annotations.Mapper;
 
import java.util.List;
 
@Mapper
public interface StudentMapper extends BaseMapper<Student> {
 
    List<Student> queryAll();
 
}

6. Mybatis layer, write sql files

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.congge.dao.StudentMapper">
 
    <select id="queryAll" resultType="com.congge.entity.Student">
		select * from student
	</select>
 
</mapper>

7. Business implementation class

In this business implementation, you can use the mybatis method and mybatis- Plus method, choose based on your own needs when using it specifically;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.congge.dao.StudentMapper;
import com.congge.entity.Student;
import com.congge.service.StudentService;
import org.springframework.stereotype.Service;
 
import javax.annotation.Resource;
import java.util.List;
 
@Service
public class StudentServiceImpl implements StudentService {
 
    @Resource
    private StudentMapper studentMapper;
 
    @Override
    public List<Student> queryAllStudent() {
        QueryWrapper<Student> queryWrapper = new QueryWrapper();
        List<Student> students = studentMapper.selectList(queryWrapper);
        return students;
        //return studentMapper.queryAll();
    }
 
    @Override
    public List<Student> getByName(String name) {
        QueryWrapper<Student> queryWrapper = new QueryWrapper();
        queryWrapper.like("name",name);
        return studentMapper.selectList(queryWrapper);
    }
 
    public Student getById(String id) {
        QueryWrapper<Student> queryWrapper = new QueryWrapper();
        queryWrapper.like("id",id);
        return studentMapper.selectOne(queryWrapper);
    }
}

8. Add a test interface

@RestController
public class StudentController {
 
    @Autowired
    private StudentService studentService;
 
    @GetMapping("/getAll")
    public List<Student> getAll(){
        return studentService.queryAllStudent();
    }
 
    @GetMapping("/getByName")
    public List<Student> getByName(@RequestParam String name){
        return studentService.getByName(name);
    }
 
    @GetMapping("/getById")
    public Student getById(@RequestParam String id){
        return studentService.getById(id);
    }
}

9. Start the class

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);
    }
 
}

Next, Run the project and test it

10. After starting, open the swagger interface

You might as well test two randomly Let’s use an interface and test it to get the data interface of all students

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