1.writeFile

//server.js

var http = require("http");
var writefile = require("./writefile");

http.createServer(function(res, res){
res.writeHead(200, {"Content-Type":"text/html; charset=uf-8"});
if (res.url!=="/favicon.ico") {
console.log('begin visit');
res.write('hello world');
writefile.writefile('./test.txt', 'gaoxiong'); //如果文件路径存在则添加数据，如果不存在则新建文件并且添加数据
res.end('end');
}
}).listen(8000);
console.log('Server running at http://127.0.0.1:8000/');

//writefile.js
var fs = require("fs");
module.exports = {
//异步方式
writefile:function(path, data){
fs.writeFile(path, data, function(err){
if (err) {
throw(err)
} else{
console.log('saved success');
}
})
},
//同步方式
writefileSync:function(path, data){
fs.writeFileSync(path, data);
console.log('同步写文件完成')
}
}