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Opret en HTTP-proxyserver i Java

HTTP

I dagens verden er proxy behovet for næsten alle. Denne vejledning viser, hvordan man opretter en HTTP-proxyserver i Java.

Opret en HTTP-proxyserver i Java

En proxyserver er en mellemliggende tilgang mellem klienten og serveren. Denne vejledning vil demonstrere en tilgang til at oprette en HTTP-proxyserver i Java.

En proxyserver har nogle fordele, som omfatter:

  1. Med proxyservere kan vi oprette statistik om trafik.
  2. Med proxyservere kan vi opdatere indholdet af klienten.
  3. Vi kan analysere problemerne med netværkssystemets reaktion med proxyservere.
  4. Vi kan bruge proxy-servere til at kontrollere grænsen for download og upload.
  5. Vi kan bruge proxy-servere til at fange trafikken mellem serveren og klienten.

Java understøtter proxy-handlere til forskellige protokoller, f.eks. HTTP, FTP, HTTPS osv. ProxyHost og ProxyPort bruges til en HTTP-proxyserver i Java.

Lad os prøve at implementere en HTTP-proxyserver i Java:

package delftstack;

import java.io.*;
import java.net.*;
public class Proxy_Server {
    public static void main(String[] args) throws IOException {
        try {
            String Proxy_Host = "Our Proxy Server";
            int Remote_Port = 1025;
            int Local_Port = 1026;
            // Printing the start-up message
            System.out.println("Starting proxy for " + Proxy_Host + ":" + Remote_Port
                + " on port " + Local_Port);
            // start the server
            Run_Server(Proxy_Host, Remote_Port, Local_Port);
        }
        catch (Exception e)
        {
            System.err.println(e);
        }
    }


    public static void Run_Server(String Proxy_Host, int Remote_Port, int Local_Port) throws IOException {
        // Create a ServerSocket to listen connections
        ServerSocket Server_Socket = new ServerSocket(Local_Port);
        final byte[] Request = new byte[1024];
        byte[] Reply = new byte[4096];
        while (true) {
            Socket Socket_Client = null, Socket_Server = null;
            try {
                // wait for a connection on the local port
                Socket_Client = Server_Socket.accept();
                final InputStream InputStreamClient = Socket_Client.getInputStream();
                final OutputStream OutputStreamClient = Socket_Client.getOutputStream();

                // Create the connection to the real server.
            try {
                Socket_Server = new Socket(Proxy_Host, Remote_Port);
            }
            catch (IOException e) {
                PrintWriter out = new PrintWriter(OutputStreamClient);
                out.print("The Proxy Server could not connect to " + Proxy_Host + ":"
                 + Remote_Port + ":\n" + e + "\n");
                out.flush();
                Socket_Client.close();
                continue;
            }


            final InputStream InputStreamServer = Socket_Server.getInputStream();
            final OutputStream OutputStreamServer = Socket_Server.getOutputStream();

            // The thread to read the client's requests and to pass them
            Thread New_Thread = new Thread() {
            public void run() {
                int Bytes_Read;
                try {
                    while ((Bytes_Read = InputStreamClient.read(Request)) != -1) {
                        OutputStreamServer.write(Request, 0, Bytes_Read);
                        OutputStreamServer.flush();
                    }
                }
                catch (IOException e) {
                }

                // Close the connections
                try {
                    OutputStreamServer.close();
                }
                catch (IOException e) {
                }
            }
        };

            // client-to-server request thread
            New_Thread.start();
            // Read server's responses and pass them to the client.
            int Bytes_Read;
            try {
                while ((Bytes_Read = InputStreamServer.read(Reply)) != -1) {
                    OutputStreamClient.write(Reply, 0, Bytes_Read);
                    OutputStreamClient.flush();
                }
            }
            catch (IOException e) {
            }
            // Close the connection
            OutputStreamClient.close();
           }
           catch (IOException e) {
               System.err.println(e);
           }
           finally {
               try {
                   if (Socket_Server != null)
                       Socket_Server.close();
                   if (Socket_Client != null)
                       Socket_Client.close();
               }
               catch (IOException e) {
               }
           }
       }
   }
}

Ovenstående kode implementerer en HTTP-proxyserver i Java. Udgangen for vellykket forbindelse er:

Starting proxy for Our Proxy Server:1025 on port 1026

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