express get和post方法

把之前学习的一个小例子贴出来：

前提：需安装nodejs，可以在终端中输入node -v检查是否安装成功，安装成功后才可执行下面的步骤。

1、新建一个名称为“node”文件夹

2、进入node目录下，运行npm init 生成package.json

npm init

3、安装express框架

npm install --save express

4、在node目录下新建一个app.js文件，并对app.js进行编辑

const express = require('express'); // 引入express
const app = express();

//设置允许跨域访问该服务
app.all('*', function (req, res, next) {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Headers', 'Content-Type');
  res.header('Access-Control-Allow-Methods', '*');
  res.header('Content-Type', 'application/json;charset=utf-8');
  next();
});

let allUserInfo = [{
  userId: 1,
  userName: '小明',
  age: '18',
  address: '浙江杭州'
}, {
  userId: 2,
  userName: '张三',
  age: '20',
  address: '浙江宁波'
}, {
  userId: 3,
  userName: '李四',
  age: '21',
  address: '浙江温州'
}];

app.get('/getUserInfo', (req, res) => {
  let getId = parseInt(req.query.userId); // 将userId变成Number类型
  let sendValue;
  // 根据传过来的userId，获取用户的info，并返回给客户端
  for (let i = 0, len = allUserInfo.length; i < len; i++) {
    if (allUserInfo[i].userId === getId) {
      sendValue = allUserInfo[i];
    }
  }
  res.send(sendValue);
});

app.post('/addUser', (req, res) => {
  let query = req.body;
  allUserInfo.push({
    userId: allUserInfo[allUserInfo.length - 1].userId + 1,
    userName: query.userName,
    age: query.age,
    address: query.address
  });
  res.send('OK');
});

const server = app.listen(3000, function () {
  console.log('Express app server listening on port %d', server.address().port);
});

5、启动服务，在node目录下，运行node app.js

node app.js

6、这时候就可以在浏览器地址栏中输入：http://localhost:3000/getUserInfo?userId=1

7、也可以在index.html用ajax请求向3000端口服务请求数据

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>express-get-post</title>
  <style>
  </style>
</head>
<body>
  <script>
    function serialize (data) {
      if (!data) {
        return '';
      }
      
      var paris = [];
      for (var key in data) {
        if (!data.hasOwnProperty(key) || typeof data[key] === 'function') {
          continue;
        }
        var name = encodeURIComponent(key);
        var value = encodeURIComponent(data[key].toString());
        paris.push(name + '=' + value);
      }
      return paris.join('&');
    }

    function request (method, url, options, callback) {
      var req;
      if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
      } else if (window.ActiveXObject) { // 兼容IE7及以下版本
        req = new ActiveXObject();
      }
      
      req.onreadystatechange = function () {
        if (req.readyState === 4) {
          if (req.status === 200) {
            console.log('请求成功');
            callback(req.response);
          }
        } else {
          console.log('请求中...');
        }
      }
      
      url = method === 'get' && serialize(options) !== '' ?  url + '?' + serialize(options) : url;
      let sendParams = method === 'get' ? null : serialize(options);
      
      req.open(method, url);
      req.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
      req.send(sendParams);
    }

    // 获取用户信息
    request('get', 'http://localhost:3000/getUserInfo', {userId: 4}, (res) => {
      console.log(res);
    });

    // 增加用户
    request('post', 'http://localhost:3000/addUser', {userName: 'liming', age: '23', address: '浙江绍兴'}, (res) => {
      console.log(res);
    });
  </script>
</body>
</html>

express get和post方法

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