In -depth understanding of the Java library technology of Jeromq framework
In -depth understanding of the Java library technology of Jeromq framework
Jeromq is a ZEROMQ library implemented with pure Java.It provides a lightweight, fast, and reliable message transmission mechanism that can simplify communication needs in distributed systems.This article will deeply understand the technical principles of the Java -class library of the Jeromq framework and show its usage through the Java code example.
1. Jeromq installation and introduction
First, we need to introduce the Jeromq framework into our Java project.You can install it by Maven or manually downloading jar package.The following is an example code that Jeromq dependencies are added through Maven:
<dependency>
<groupId>org.zeromq</groupId>
<artifactId>jzmq</artifactId>
<version>3.1.0</version>
</dependency>
2. Basic use of Jeromq
Jeromq supports a variety of message transmission modes, such as request-response, release-subscription and push-pulling, etc.Below we will use the request-response mode as an example to show the basic usage of Jeromq.
First, we will have a sender and a responder.The sender will send a message request, and the receiver will return the response.The following is a simple example code:
import org.zeromq.SocketType;
import org.zeromq.ZMQ;
import org.zeromq.ZContext;
public class JeroMQExample {
public static void main(String[] args) {
try (ZContext context = new ZContext()) {
// Create the request party socket
ZMQ.Socket requester = context.createSocket(SocketType.REQ);
requester.connect("tcp://localhost:5555");
// Send a request message
String requestMessage = "Hello";
requester.send(requestMessage.getBytes(), 0);
// Receive response messages
byte[] responseBytes = requester.recv(0);
String responseMessage = new String(responseBytes);
System.out.println("Received response: " + responseMessage);
}
}
}
In the above example, we created a ZContext object to manage Jeromq -related contexts.Then, we use the context to create a socket. The type of the socket is REQ, indicating the request party.Through the Connect method, we connect the socket to a target address and port number.Then, we use the send method to send a request message and use the RECV method to receive the response message.
In another Java process, we can create a corresponding receiver to process the request message and send a response message.The following is the example code of the receiver:
import org.zeromq.SocketType;
import org.zeromq.ZMQ;
import org.zeromq.ZContext;
public class JeroMQExample {
public static void main(String[] args) {
try (ZContext context = new ZContext()) {
// Create the receiver socket
ZMQ.Socket responder = context.createSocket(SocketType.REP);
responder.bind("tcp://*:5555");
// Receive the request message
byte[] requestBytes = responder.recv(0);
String requestMessage = new String(requestBytes);
System.out.println("Received request: " + requestMessage);
// Send the response message
String responseMessage = "World";
responder.send(responseMessage.getBytes(), 0);
}
}
}
In the above example, we also use ZContext to create and manage the context of Jeromq.We created a Socket, which is the type of the socket, indicating the receiver.Use the Bind method to bind the socket to a port number.
When the requestant sends a request message, the receiver uses the RECV method to receive the request message and use the send method to send a response message.
3. Jeromq's advanced usage
In addition to request-answer mode, Jeromq also supports many other message transmission modes.Here are some common examples:
-Poltage-Subscribe mode:
import org.zeromq.SocketType;
import org.zeromq.ZMQ;
import org.zeromq.ZContext;
public class JeroMQExample {
public static void main(String[] args) {
try (ZContext context = new ZContext()) {
// Create the publisher socket
ZMQ.Socket publisher = context.createSocket(SocketType.PUB);
publisher.bind("tcp://*:5555");
// make an announcement
String message = "This is a pub-sub message";
publisher.sendMore(topic).send(message.getBytes());
}
}
}
-Plement-Pulling mode:
import org.zeromq.SocketType;
import org.zeromq.ZMQ;
import org.zeromq.ZContext;
public class JeroMQExample {
public static void main(String[] args) {
try (ZContext context = new ZContext()) {
// Create a push -free Socket
ZMQ.Socket pusher = context.createSocket(SocketType.PUSH);
pusher.connect("tcp://localhost:5555");
// Send a message
String message = "This is a push-pull message";
pusher.send(message.getBytes());
}
}
}
Through the above examples, we have a deep understanding of the Java class library technical principles of the Jeromq framework and provide some common examples of usage.Through Jeromq, we can easily realize the efficient and reliable message transmission mechanism, thereby simplifying communication needs in distributed systems.
