Spring Boot应用连接数据库MySQL、及一个简单的demo

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。

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

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-8
spring.datasource.username=root
spring.datasource.password=159753
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.max-idle=10
spring.datasource.max-wait=1000
spring.datasource.min-idle=5
spring.datasource.initial-size=5
server.port=8080
server.servlet.session.timeout=10
server.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;

@Service
public class StudentService {
    @Autowired StudentDao studentDao;
    public List<Student> 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<Student> 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;
@RestController
public class StudentController {
    @Autowired
    StudentService studentService;
    @ResponseBody
    @RequestMapping("/student")
    public List<Student> 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