如何判断浏览器的请求头是不是结束

\r\n\r\n好像是结束符package com.maple.detail3;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class TcpServer3 {
public static void main(String[] args) throws Exception {

ServerSocket serverSocket=new ServerSocket(10000);
Thread t=null;
while(true)
{
Socket socket=serverSocket.accept();
t=new Thread(new ReadPic(socket));
t.start();
}
}

}

class ReadPic implements Runnable
{
Socket socket=null;

public ReadPic(Socket socket) {
this.socket=socket;
}

@Override
public void run() {
try {
OutputStream outputStream=socket.getOutputStream();
InputStream inputStream=new FileInputStream("c:/2.png");

InputStream socketInputStream=socket.getInputStream();

byte[] buf=new byte[1024];
int len=0;

while((len=socketInputStream.read(buf))!=-1)
{
String line=new String(buf,0,len);
System.out.println(line.length()+" "+line);
if(line.endsWith("\r\n\r\n"))
{
System.out.println("game is over");
break;
}
}
System.out.println("kkkkkkkkkkkkkkkk");
while((len=inputStream.read(buf))!=-1)
{
outputStream.write(buf,0,len);
outputStream.flush();
}
socket.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}