events模块

/**
 * Created by Administrator on 2016/8/3.
 */
var http = require("http");
//Node 导入文件系统模块
var fs = require("fs");
//引入events模块
var events = require("events");
//创建eventEmitter对象
var eventEmitter = new events.EventEmitter(); //注意大小写
//绑定事件以及事件的处理程序
eventEmitter.on("oneEvent",function(){
    //异步读取文件内容的函数: readFile()
    fs.readFile("index.txt", "utf-8", function(err, data){
        if(err){
            console.log(err);
        }else{
            console.log(data);
        }
    });
    console.log("end异步");
});
//触发事件
eventEmitter.emit("oneEvent");
function start(req, res){
    res.writeHead(200, {"Content-Type": "text/plain"});
    res.write("异步读取文件和同步读取文件的对比！");
    res.end("over");
}
//创建一个http服务器，并监听端口号为3001，host为127.1.1.1
var server = http.createServer(start).listen("3002","127.1.1.1",function(){
    var port = server.address().port;
    var host = server.address().address;
    console.log("应用实例，访问地址为 http://%s:%s", host, port);
});

//引入events模块
var events = require("events");

//创建eventEmitter对象
var eventEmitter = new events.EventEmitter(); //注意大小写

//绑定事件以及事件的处理程序
eventEmitter.on("eventName",function(){
    console.log("事件处理代码。");
});
//触发事件
eventEmitter.emit("eventName");