重新发送收到的HTTP请求 - 已发送的标头

Question

我有一个项目，该过程将http请求发送到必须处理长http请求的Web服务器，但如果其中一个服务器崩溃，我需要重新发送崩溃的Web服务器计算到另一个Web服务器的请求这是有用的。

问题是在我的解决方案中我已经发送了IOException标头。该项目的代码很大，所以我构建了一些流程样本，重定向请求以尝试解决此问题，这里是：

import java.io.IOException;
import java.net.InetSocketAddress;
import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;

public class Principal {

static Request request;

public static void main(String[] args) throws IOException  
    {
   HttpServer server = HttpServer.create(new InetSocketAddress(8000), 0);
       server.createContext("/f.html", new MyHandler());
       server.setExecutor(null); // creates a default executor
       server.start();
       System.out.println("Server ready");  
}

    public static void resend()
    {
       Thread thread = new MyThread(request.getRequest(), "52.18.4.134");
   thread.start();          
    }

static class MyHandler implements HttpHandler
{

    @Override
    public void handle(HttpExchange t) throws IOException {
        request = new Request("30",t);

        //each request received will be treated by a different thread
         Thread thread = new MyThread(t, "52.31.116.250");
         //Thread thread = new Connection.MyThread(t, "52.50.47.25");
         thread.start();                                
    }

}

static class MyThread extends Thread 
 {
    private String numeroFatorizar;
    String query;
    HttpExchange t;
    private String destinationIP; //IP of the instance to send the request

    public MyThread(HttpExchange t, String destinationIP)
    {
        this.destinationIP = destinationIP;
        this.t = t;
        query = t.getRequestURI().getQuery(); 
        if(query != null) 
        {
            String[] parts = query.split("=");
            numeroFatorizar = parts[1];     
        }

    }

    @Override
    public void run()
    {   
        //redirects to web servers
        try {
            t.getResponseHeaders().add("Location", "http://"+destinationIP+":8000/f.html/numeroFatorizar?="+numeroFatorizar);
            t.sendResponseHeaders(301,0);
            t.getResponseBody().close();

             resend();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }   
}
}

当调用resend（）尝试发送到不同的IP时，我会收到“已发送的标题”。我需要向第二个IP发送相同的http请求，因为它包含响应对象。

我在开头就有的请求代码就是这样：

public class Request {
//classe que carateriza um pedido

    private String parameter; //parameter to be factorized
    private HttpExchange request; //contains client request

    public Request(String parameter, HttpExchange request)
    {
        this.parameter = parameter;
        this.request = request;
    }

    public HttpExchange getRequest() {
        return request;
    }
}