如何在java中发送'SIP请求'（SIP客户端）

Question

I'm setting up a new client, and want to send SIP request using JAVA. I have followed some steps but to no avail.

For example, when sending a request from the client is not given a response from the server ... I think that the HEADER contains errors

import java.io.IOException;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;


public class Client
{

    public static void main(String args[]) throws IOException
    {
        Socket socket = new Socket("104.207.221.19", 5060);

        Scanner userInput = new Scanner(System.in);
        Scanner socketInput = new Scanner(socket.getInputStream());

        PrintStream socketOutput = new PrintStream(socket.getOutputStream());

        String Request = "";
        Request = "INVITE sip:bob@domain.com SIP/2.0 \r\n";
        Request += "Via: SIP/2.0/UDP nm;received=51.40.80.23 \r\n";
        Request += "From: <sip:nm@nm>;tag=root \r\n";
        Request += "To: <sip:nm2@nm2>;tag=dff4305d81b6facb \r\n";
        Request += "Call-ID: 50000 \r\n";
        Request += "CSeq: 42 OPTIONS \r\n";
        Request += "Content-Type: application/sdp \r\n";
        Request += "Content-Length: 142";
        Request += "\r\n\r\n";

        socketOutput.print(Request);

        while(socketInput.hasNextLine())
            System.out.println(socketInput.nextLine());

    }

}

I expect the output will be the response of the server, but the actual no output occurs.

Answer 1

Your headers say Content-Length: 142 but you are not sending any content - there is no body to the request. So I think that the server is waiting for the 142 bytes of content to arrive before it responds. Try setting the content length to zero.

(Actually I think you are sending 2 bytes of content because you have a spare \\r\\n at the end, but definitely not 142 bytes)