var express = require("express");//网络请求模块var request = require("request");//引入nodejs文件系统模块const fs = require('fs');//引入body-parser//包含在请求正文中提交的键/值对数据。 //默认情况下，它是未定义的，并在使用body-parser中间件时填充。var bodyParser = require('body-parser');var app = express();//解析 application/x-www-form-urlencoded，limit:'20mb'用于设置请求的大小//解决nodejs Error: request entity too large问题app.use(bodyParser.urlencoded({ limit:'20mb',extended: true })); //设置跨域访问app.all('*', function(req, res, next) {  res.header("Access-Control-Allow-Origin", "*");  res.header("Access-Control-Allow-Headers", "X-Requested-With");  res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");  res.header("Content-Type", "application/json;charset=utf-8");  next();});//上传图片app.post('/upload',function(req,res){  var imgData = req.body.url;  var base64Data = imgData.replace(/^data:image///w+;base64,/, "");  var dataBuffer = new Buffer(base64Data, 'base64');  fs.writeFile("image.png", dataBuffer, function(err) {    if(err){      res.send(err);    }else{      res.send("保存成功！");    }  });})var server = app.listen(4444, function() {  console.log('监听端口 4444');});

 //上传图片 /* *   let data = { *    size: '125422', *    type: 'image/jpeg', *    name: 'test.jpg', *    url: base64 *   }; *获取图片的base64码可以通过FileReader获取 */ uploadImage(data) {  return new Promise((resolve, reject) => {   let headers = new Headers({    'Content-Type': 'application/x-www-form-urlencoded'   });   let options = new RequestOptions({    headers: headers   });   this.http.post("http://localhost:4444/upload", this.toQueryString(data),options)    .map(res => res.json())    .subscribe(data => { resolve(data), error => { reject(error) } })  }) }// JSON参数序列化  private toQueryString(obj) {   let result = [];   for (let key in obj) {    key = encodeURIComponent(key);    let values = obj[key];    if (values && values.constructor == Array) {     let queryValues = [];     for (let i = 0, len = values.length, value; i < len; i++) {      value = values[i];      queryValues.push(this.toQueryPair(key, value));     }     result = result.concat(queryValues);    } else {     result.push(this.toQueryPair(key, values));    }  }   return result.join('&');  }  private toQueryPair(key, value) {   if (typeof value == 'undefined') {    return key;   }   return key + '=' + encodeURIComponent(value === null ? '' : String(value));  }