nodejs 网上下载图片到本地，并判断图片路径是否存在

var http = require("http");
var fs = require("fs");

var server = http.createServer(function(req, res){}).listen(50082);
var url = "http://s0.hao123img.com/res/img/logo/logonew.png";

//随机获取名称
function getName(){
	var timer = new Date();
	var arr = JSON.stringify(timer).replace(/:|-|"/g ,'').split('.');
	var str = arr.join('');
	console.log(str);
	return str;
}

load(url);
function load(url){
	http.get(url, function(res){
    var imgData = "";
    res.setEncoding("binary"); //一定要设置response的编码为binary否则会下载下来的图片打不开
    res.on("data", function(chunk){
        imgData+=chunk;
    });
    res.on("end", function(){
    	if(imgData){
    		console.log('下载成功!');
    		var path = "./image/"+getName()+".png";
    		console.log(path);
    		fs.writeFile(path, imgData, "binary", function(err){
	            if(err){
	                console.log("down fail");
	            }
	            console.log("down success");
	        });
    	}else{
    		console.log('下载失败！,图片路径不存在！');
    	}

    });
});
}