SpringBoot 1024行代码 - 用JPA访问MySQL

前言

访问关系型数据库是Web工程常见的需求。MySQL是当今业界应用最广泛的开源关系型数据库。Spring Boot全家桶提供了JPA，可以让开发者方便快捷地开发出访问MySQL的业务代码。

准备工作

1 安装jdk1.8
2 安装maven
3 具备Spring和SpringMVC的基础知识

具体步骤

1. 搭建一个MySQL数据库，创建一个名叫test的数据库，在test库中创建一个user表

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(45) DEFAULT NULL,
  `phone` varchar(45) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8

2. 在pom.xml中加入Spring Boot中跟MySQL相关的引用

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.8.RELEASE</version>
    </parent>

    <dependencies>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- JPA Data (We are going to use Repositories, Entities, Hibernate, etc...) -->

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <!-- Use MySQL Connector-J -->

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

3. 创建一个程序入口类

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

4. 修改application.properties文件，添加MySQL的配置

spring.jpa.hibernate.ddl-auto=none
spring.datasource.url=jdbc:mysql://localhost:3306/test?useSSL=false
spring.datasource.username=root
spring.datasource.password=

5. 添加一个user表对应的实体类User

package com.example.demo.entity;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy= GenerationType.AUTO)
    private Integer id;

    private String name;

    private String phone;

    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 String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }
}

6. 创建一个UserRepository接口

package com.example.demo.repository;

import com.example.demo.entity.User;
import org.springframework.data.repository.CrudRepository;

public interface UserRepository extends CrudRepository<User, Integer> {
}

7. 创建一个测试方法

package com.example.demo.controller;

import com.example.demo.entity.User;
import com.example.demo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class UserController {

    @Autowired
    private UserRepository userRepository;

    /**
     * add user
     * @param name
     * @param phone
     * @return
     */
    @RequestMapping(path="/user", method = RequestMethod.POST)
    @ResponseBody
    public String addNewUser (@RequestParam String name, @RequestParam String phone) {
        User n = new User();
        n.setName(name);
        n.setPhone(phone);
        userRepository.save(n);
        return "Success";
    }
}

8. 调用接口添加一条数据到mysql

curl -X POST 127.0.0.1:8080/user -d 'name=tom&phone=654321'

观察数据库user表，发现增加了一条新数据

源码

https://github.com/gzllol/spr...