用springboot和React做一个简单的前后端的小系统

首先建库（Mysql不知道怎么建的先学）

建立一个**test**数据库，然后创一个**user**数据表：
表结构如下：

创建Springboot项目（后台）

直接下一步

添加web模块

添加数据库模块：

为你的后台模块取个名字（我的是springbootdemo3）

创建好了之后首先打开application.propertiies：

在里面加上：

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC&characterEncoding=utf8&allowMultiQueries=true
spring.datasource.username=root
spring.datasource.password=你的密码

spring.jpa.show-sql=true

在src中创建如下包结构：example/demo/user下有三个class：

User:

package com.example.demo.user;

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

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer uid;
    private String name;
    private String age;
    private String telephone;
    private String email;
    private String job;

    public Integer getUid() {
        return uid;
    }
    public void setUid(Integer uid) {
        this.uid = uid;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAge() {
        return age;
    }
    public void setAge(String age) {
        this.age = age;
    }
    public String getTelephone() {
        return telephone;
    }
    public void setTelephone(String telephone) {
        this.telephone = telephone;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getJob() {
        return job;
    }
    public void setJob(String job) {
        this.job = job;
    }
    public User(){
    }
}

UserController

package com.example.demo.user;
import org.springframework.web.bind.annotation.*;
import java.util.List;

@RestController
@RequestMapping("/api/users")
public class UserController {
    private UserRepository userRepository;
    public UserController(UserRepository userRepository) {
        this.userRepository = userRepository;
    }
    @GetMapping//查
    public List<User> getList() {
        return userRepository.findAll();
    }
    @PostMapping//改和增
    public User addUser(@RequestBody User user) {
        return userRepository.save(user);
    }
    @DeleteMapping(value = "/{uid}")//删
    public void delUser(@PathVariable("uid") Integer uid
    ) {
        userRepository.deleteById(uid);
    }
}

UserRepository(Jpa接口，有各种对数据库操作的方法)

package com.example.demo.user;
import org.springframework.data.jpa.repository.JpaRepository;
public interface UserRepository extends JpaRepository<User,Integer> {
}

后台写完

创建React项目（前端）

idea新建工程：

输入名字：

建好以后目录：

在src下创建包components,components里创建JavaScript文件UserLIst:

import React, {Component} from 'react';
import 'isomorphic-fetch';//fetch需要用node安装，没有的可以去下载一下
import {Button} from 'react-bootstrap';//同上

export default class userList extends Component {
  constructor() {
    super();
    this.state = {}
  }
  async componentDidMount() {
    let users = await (await fetch(`/api/users`)).json();//主要是从后台拿json数据
    this.setState({users});
  }
  render() {
    let {users = []} = this.state;

    return (
      <div>
        <table className='table'>
          <thead>
          <tr>
            <th>id</th>
            <th>姓名</th>
            <th>年龄</th>
            <th>电话</th>
            <th>邮箱</th>
            <th>职位</th>
            <th>编辑</th>
          </tr>
          </thead>
          <tbody>
          {users.map(({uid, name, age, telephone, job, email}) =>
            <tr key={uid}>
              <td>{uid}</td>
              <td>{name}</td>
              <td>{age}</td>
              <td>{telephone}</td>
              <td>{email}</td>
              <td>{job}</td>
              <td><Button onClick = {() => {
                this.setState({users});
              }}>配置</Button></td>
            </tr>
          )}
          </tbody>
        </table>
      </div>
    );
  }
}

再配置一下index.js

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import * as serviceWorker from './serviceWorker';
import {BrowserRouter, Route} from "react-router-dom";
import UserList from "./components/UserList";
import 'bootstrap/dist/css/bootstrap.css';//样式，可以去除

ReactDOM.render((
  
    

      
    
  
),
  document.getElementById('root'));
// If you want your app to work offline and load faster, you can change
// unregister() to register() below. Note this comes with some pitfalls.
// Learn more about service workers: https://bit.ly/CRA-PWA
serviceWorker.unregister();

准备启动

找到这个后台启动按钮，首先启动后台。

然后启动React,然后一般页面会直接弹出来，如果没弹出来，那访问http://localhost:3000/就OK了，页面如下：

就拿到后台数据啦，很方便的哈

我也是新手入门，如果有错误的地方还请大家多多批评指正！