buffer正确的拼接方式

var chunks = [];

var size = 0;

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

chunks.push(chunk);

size+= chunk.length;

});

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

var buf = Buffer.concat(chunks,size);

var str= iconv.decode(buf,'utf8'); //引入iconv-lite

console.log(str);

});