SpringBoot Service和Dao的编写详解

create table `student` (
	`id` int(11) Not NULL AUTO_INCREMENT COMMENT '主键自增id',
	`name` varchar(250) NOT NULL DEFAULT ' ' COMMENT '姓名',
	PRIMARY KEY(`id`)
)ENGINE=INNODB DEFAULT CHARSET=utf8;

<!--    connect-->
<!--    不同版本mybatis对应boot版本不同-->
    <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>2.1.1</version>
    </dependency>
<!--    mysql版本可以不指定-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>

# mysql
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/rxguo_test?serverTimezone=UTC&characterEncoding=utf8&useSSL=false
spring.datasource.username=root
spring.datasource.password=

package com.bennyrhys.com.shop.bean;

public class Student {
  Integer id;
  String name;

  public Integer getId() {
    return id;
  }

  public void setId(Integer id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  @Override
  public String toString() {
    return "Student{" +
        "id=" + id +
        ", name='" + name + '\'' +
        '}';
  }
}

package com.bennyrhys.com.shop;

import com.bennyrhys.com.shop.bean.Student;
import com.bennyrhys.com.shop.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class StudentController {
  @Autowired
  StudentService studentService;

  @GetMapping("/student")
  public String getStudentById(@RequestParam Integer id) {
    Student student = studentService.getStudentById(id);
    return student.toString();
  }
}

package com.bennyrhys.com.shop.service;

import com.bennyrhys.com.shop.bean.Student;
import com.bennyrhys.com.shop.mapper.StudentMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class StudentService {

  @Autowired
  StudentMapper studentMapper;

  public Student getStudentById(Integer id) {
    return studentMapper.getStudentById(id);
  }
}

package com.bennyrhys.com.shop.mapper;

import com.bennyrhys.com.shop.bean.Student;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.springframework.stereotype.Repository;


@Mapper
@Repository
public interface StudentMapper {
  @Select("select * from student where id = #{id}")
  Student getStudentById(Integer id);
}