一、修改pom.xml文件

　　在项目的pom.xml文件上增加如下代码，添加依赖文件。

       
      
       mysql
        
      
       mysql-connector-java
      
     
       
      
       org.springframework.boot
        
      
       spring-boot-starter-jdbc
      
     
       
      
       org.springframework.boot
        
      
       spring-boot-starter-data-jpa
      
     

二、设置全局配置文件

　　在src/main/resources/application.properties中设置数据源和jpa配置。标红处是自己建的库

spring.datasource.url=jdbc:mysql://123.207.46.41:3306/gwfdemo?useUnicode=true&characterEncoding=utf-8spring.datasource.username=rootspring.datasource.password=159753spring.datasource.driver-class-name=com.mysql.jdbc.Driverspring.datasource.max-idle=10spring.datasource.max-wait=1000spring.datasource.min-idle=5spring.datasource.initial-size=5server.port=8080server.servlet.session.timeout=10server.tomcat.uri-encoding=UTF-8

三、分层业务逻辑

　　POJO：domain层

package com.example.demo.Domain;public class Student {    private Integer id;    private String name;    private Integer age;    private String grade;    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;    }    public Integer getAge() {        return age;    }    public void setAge(Integer age) {        this.age = age;    }    public String getGrade() {        return grade;    }    public void setGrade(String grade) {        this.grade = grade;    }}

　　service层：

package com.example.demo.Service;import com.example.demo.Dao.StudentDao;import com.example.demo.Domain.Student;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import java.util.List;@Servicepublic class StudentService {    @Autowired StudentDao studentDao;    public List
     
       getAll(){        return studentDao.getAll();    }}
     

　　dao层：

package com.example.demo.Dao;import com.example.demo.Domain.Student;import org.apache.ibatis.annotations.Select;import java.util.List;public interface StudentDao {    @Select("select * from student")    public List
     
       getAll();}
     

　　Controller层：

package com.example.demo.controller;import com.example.demo.Domain.Student;import com.example.demo.Service.StudentService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.bind.annotation.RestController;import java.util.List;@RestControllerpublic class StudentController {    @Autowired    StudentService studentService;    @ResponseBody    @RequestMapping("/student")    public List
     
       getStudents(){        return studentService.getAll();    }}
     

　　然后运行，即可查出数据，很简单的一个demo，但是代码结构大部分如此