ZeroMQ Hello World 示例

在這個例子中，我們將使用 REQ-REP（請求 - 回覆）套接字建立一個簡單的客戶端和伺服器。客戶端向伺服器傳送 Hello，伺服器回覆 World。伺服器在埠 5555 上開啟 ZeroMQ REP 套接字，讀取其上的請求，並向每個請求回覆 World。

C 中的 Hello World 伺服器：

#include <zmq.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>

int main (void)
{
    //  Socket to talk to clients
    void *context = zmq_ctx_new ();
    void *responder = zmq_socket (context, ZMQ_REP);
    int rc = zmq_bind (responder, "tcp://*:5555");
    assert (rc == 0);

    while (1) {
        char buffer [10];
        zmq_recv (responder, buffer, 10, 0);
        printf ("Received Hello\n");
        sleep (1);          //  Do some 'work'
        zmq_send (responder, "World", 5, 0);
    }
    return 0;
}

Java 中的 Hello World 伺服器：

import org.zeromq.ZMQ;

public class hwserver {

    public static void main(String[] args) throws Exception {
        ZMQ.Context context = ZMQ.context(1);

        //  Socket to talk to clients
        ZMQ.Socket responder = context.socket(ZMQ.REP);
        responder.bind("tcp://*:5555");

        while (!Thread.currentThread().isInterrupted()) {
            // Wait for next request from the client
            byte[] request = responder.recv(0);
            System.out.println("Received Hello");

            // Do some 'work'
            Thread.sleep(1000);

            // Send reply back to client
            String reply = "World";
            responder.send(reply.getBytes(), 0);
        }
        responder.close();
        context.term();
    }
}

C 中的 Hello World 客戶端：

#include <zmq.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>

int main (void)
{
    printf ("Connecting to hello world server…\n");
    void *context = zmq_ctx_new ();
    void *requester = zmq_socket (context, ZMQ_REQ);
    zmq_connect (requester, "tcp://localhost:5555");

    int request_nbr;
    for (request_nbr = 0; request_nbr != 10; request_nbr++) {
        char buffer [10];
        printf ("Sending Hello %d…\n", request_nbr);
        zmq_send (requester, "Hello", 5, 0);
        zmq_recv (requester, buffer, 10, 0);
        printf ("Received World %d\n", request_nbr);
    }
    zmq_close (requester);
    zmq_ctx_destroy (context);
    return 0;
}

Java 中的 Hello World 客戶端：

import org.zeromq.ZMQ;

public class hwclient {

    public static void main(String[] args) {
        ZMQ.Context context = ZMQ.context(1);

        //  Socket to talk to server
        System.out.println("Connecting to hello world server…");

        ZMQ.Socket requester = context.socket(ZMQ.REQ);
        requester.connect("tcp://localhost:5555");

        for (int requestNbr = 0; requestNbr != 10; requestNbr++) {
            String request = "Hello";
            System.out.println("Sending Hello " + requestNbr);
            requester.send(request.getBytes(), 0);

            byte[] reply = requester.recv(0);
            System.out.println("Received " + new String(reply) + " " + requestNbr);
        }
        requester.close();
        context.term();
    }
}

注意： REQ-REP zeromq 套接字是阻塞的，所以當客戶端（REQ）傳送訊息時，除非他從伺服器收到響應，否則他不能做任何其他事情，反之亦然 - 直到伺服器（REP）收到來自客戶，他不能傳送任何東西。