nodejs文件流

1.输入输出流三种方式：

(1)  读取图片

varfs=require('fs');

varcontentText=fs.readFileSync('444.jpg','base64');  //文本用utf8

vardataBuffer= newBuffer(contentText,'base64');//把base64码转成buffer对象，

fs.writeFile('999.jpg',dataBuffer,function(err) {

if(err){

console.log('eerr');

return;

}

console.log("ok");

})

(2)没有回调函数的

functioncreateFileName(){

vardate=newDate().valueOf();//将时间转换成毫秒

varrandom=Math.random();

returndate+''+random;

}

varfs=require('fs');

varreadStream=fs.createReadStream('kk.txt');

// readStream.setEncoding('utf8');

varwriteStream=fs.createWriteStream(createFileName()+'.txt');

readStream.pipe(writeStream);

(3)用监听读取文件流

var fs=require('fs');

var readStream=fs.createReadStream('8.png');

// readStream.setEncoding('utf8');

varwriteStream=fs.createWriteStream(createFileName()+'.png');

varcontent='';

readStream.on('data',function(chunk){

content=chunk;

});

readStream.on('end',function(){

console.log(content.toString());

writeStream.write(content,'utf8');

writeStream.end();});

readStream.on('error',function(err){

console.log(err.message);

});