创建tcp服务器

//  使用createServer()var net = require('net')const PORT = 9999const HOST = '127.0.0.1'var clientHandler = function(socket){    console.log('建立连接')    socket.on('data',function(data){        console.log(socket.remoteAddress,socket.remotePort,'send',data.toString())        socket.write('server receiver\n')    })    socket.on('close',function(){        consloe.log(socket.remoteAddress,socket.remotePort,'disconnected')    })}var app = net.createServer(clientHandler);app.listen(PORT,HOST)

// 使用核心模块net 创建socket   var net = require('net')var tcpClient = net.Socket()tcpClient.connect(9999,'127.0.0.1',function(){    console.log('connect success.')    tcpClient.write('tcpClient')})tcpClient.on('data',function(data){    console.log(data.toString())})