问题
I am trying to implement using XPUB and XSUB as provided in this below figure. I have gone through their examples provided but could not get one for XPUB and XSUB in Java. Here they have given an example in C which is little complex as I am new to ZeroMQ.
I am trying to use it in android using jni wrapped version. Please help me to find an example, how to implement this Pub-Sub Network with a Proxy in ZeroMQ using java.
Currently I am referring http://zguide.zeromq.org/page:all
I have tried to port it as follows. Subscriber.java
public class Subscriber extends Thread implements Runnable {
private static final String TAG = "Subscriber";
private Context ctx;
public Subscriber(ZMQ.Context z_context) {
this.ctx = z_context;
}
@Override
public void run() {
super.run();
ZMQ.Socket mulServiceSubscriber = ctx.socket(ZMQ.SUB);
mulServiceSubscriber.connect("tcp://localhost:6001");
mulServiceSubscriber.subscribe("A".getBytes());
mulServiceSubscriber.subscribe("B".getBytes());
while (true) {
Log.d(TAG, "Subscriber loop started..");
String content = new String(mulServiceSubscriber.recv(0));
Log.d(TAG, "Subscriber Received : "+content);
}
}
}
Publisher.java
public class Publisher extends Thread implements Runnable {
private static final String TAG = "Publisher";
private Context ctx;
public Publisher(ZMQ.Context z_context) {
this.ctx = z_context;
}
@Override
public void run() {
super.run();
ZMQ.Socket publisher = ctx.socket(ZMQ.PUB);
publisher.connect("tcp://localhost:6000");
while (true) {
Log.d(TAG, "Publisher loop started..");
publisher.send(("A Hello " + new Random(100).nextInt()).getBytes() , 0);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
XListener.java (For now a simple Forwarder)
public class XListener extends Thread implements Runnable {
private static final String TAG = null;
private Socket publisherX;
private Context ctx;
private Socket subscriberX;
public XListener(ZMQ.Context ctx, ZMQ.Socket subscriberX,
ZMQ.Socket publisherX) {
this.ctx = ctx;
this.subscriberX = subscriberX;
this.publisherX = publisherX;
}
@Override
public void run() {
super.run();
while (true) {
Log.d(TAG, "XListener loop started..");
String msg = new String(subscriberX.recvStr());
Log.v(TAG, "Listener Received: " +"MSG :"+msg);
publisherX.send(msg.getBytes(), 0);
}
}
}
in application main()
private void main() {
ZMQ.Context ctx = ZMQ.context(1);
ZMQ.Socket subscriberX = ctx.socket(ZMQ.XSUB);
subscriberX.bind("tcp://*:6000");
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
ZMQ.Socket publisherX = ctx.socket(ZMQ.XPUB);
publisherX.bind("tcp://*:6001");
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
new XListener(ctx, subscriberX, publisherX).start();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
new XSender(ctx, subscriberX, publisherX).start();
try {
Thread.sleep(500);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
new Subscriber(ctx).start();
new Publisher(ctx).start();
}
With the code I am not able to listen XSUB. While porting espresso.c, I was not able to find any wrapper in java bindings of ZMQ. How to implement a simple proxy or am I missing something??
回答1:
Wow I'm answering my own question. I missed to add a forwarder from publisherX to subscriberX. Here is the missing code. Now XSUB and XPUB are able to send and get data.
public class XSender extends Thread implements Runnable {
private static final String TAG = null;
private Socket publisherX;
private Context ctx;
private Socket subscriberX;
public XSender(ZMQ.Context ctx, ZMQ.Socket subscriberX,
ZMQ.Socket publisherX) {
this.ctx = ctx;
this.subscriberX = subscriberX;
this.publisherX = publisherX;
}
@Override
public void run() {
super.run();
while (true) {
// Read envelope with address
Log.d(TAG, "XListener loop started..");
String msg = new String(subscriberX.recv(0));
Log.v(TAG, "Listener Received: " +"MSG :"+msg);
publisherX.send(msg.getBytes(), 0);
}
}
}
来源：https://stackoverflow.com/questions/14516102/how-to-implement-pub-sub-network-with-a-proxy-by-using-xpub-and-xsub-in-zeromqj