{
 "css": "text/css",
 "gif": "image/gif",
 "html": "text/html",
 "ico": "image/x-icon",
 "jpeg": "image/jpeg",
 "jpg": "image/jpeg",
 "js": "text/javascript",
 "json": "application/json",
 "pdf": "application/pdf",
 "png": "image/png",
 "svg": "image/svg+xml",
 "swf": "application/x-shockwave-flash",
 "tiff": "image/tiff",
 "txt": "text/plain",
 "wav": "audio/x-wav",
 "wma": "audio/x-ms-wma",
 "wmv": "video/x-ms-wmv",
 "xml": "text/xml"
}

//设置请求的返回头type,content的type类型列表见上面
response.setHeader("Content-Type", contentType);
//格式必须为 binary 否则会出错
var content = fs.readFileSync(url,"binary"); 
response.writeHead(200, "Ok");
response.write(content,"binary"); //格式必须为 binary，否则会出错
response.end();

response.set( 'content-type', mimeType );//设置返回类型
var stream = fs.createReadStream( imageFilePath );
var responseData = [];//存储文件流
if (stream) {//判断状态
 stream.on( 'data', function( chunk ) {
  responseData.push( chunk );
 });
 stream.on( 'end', function() {
  var finalData = Buffer.concat( responseData );
  response.write( finalData );
  response.end();
 });
}