一、修改server.js

var http = require("http");var url = require("url"); //导入内置url模块function start(route){    function onRequest(request, response){        var pathname = url.parse(request.url).pathname; //提取url        console.log("Request received.");        console.log("Request for " + pathname + " received.")        route(pathname) //路由        response.writeHead(200, {"Content-Type": "text/plain"});        response.write("Hello,World,Node.js");        response.end();    }    http.createServer(onRequest).listen(8888);    console.log("Server has started.")}exports.start = start

二、增加router.js

内容如下，

function route(pathname){    console.log("About to route a request for" + pathname);}exports.route = route

三、修改index.js

var server = require("./server")var router = require("./router")server.start(router.route)