【SpringBoot】Service和Dao的编写

效果图

配置环境

创建数据库

数据库中文编码

建表

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;

pom依赖和配置

mybatis 和 mysql

<!--        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>

application.properties

# 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=

java

bean

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 + '\'' +
                '}';
    }
}

Controller

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();
    }
}

Service

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);
    }
}

Mapper接口

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);
}