How Java uses the Grizzly Framework to achieve network communication
The Grizzly Framework is a high-performance and scalable network communication framework based on Java. It provides a set of APIs and tools for building efficient and scalable Web application. The core of the Grizzly Framework is its NIO engine and event driven message processing model.
Advantages:
1. High performance: The Grizzly Framework uses NIO technology, supports non blocking I/O operations, and can handle a large number of concurrent connections.
2. Extensibility: Through the event driven model, Web application can be easily extended and customized.
3. Simplify network programming: The Grizzly Framework provides a series of advanced features, such as HTTP encoding/decoding, WebSocket support, load balancing, etc., simplifying the complexity of network programming.
Disadvantages:
1. The Learning curve is steep: the use of the Grizzly Framework requires a certain learning cost, especially for beginners.
2. Relatively incomplete documentation: Compared to some other network communication frameworks, the Grizzly Framework has relatively fewer documents and materials.
The following is a Java sample code for implementing network communication using the Grizzly Framework:
Client code:
import org.glassfish.grizzly.Buffer;
import org.glassfish.grizzly.CompletionHandler;
import org.glassfish.grizzly.Connection;
import org.glassfish.grizzly.Grizzly;
import org.glassfish.grizzly.attributes.Attribute;
import org.glassfish.grizzly.filterchain.FilterChainBuilder;
import org.glassfish.grizzly.filterchain.TransportFilter;
import org.glassfish.grizzly.nio.NIOTransport;
import org.glassfish.grizzly.nio.transport.TCPNIOTransport;
import org.glassfish.grizzly.threadpool.ThreadPoolConfig;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
public class Client {
public static void main(String[] args) throws IOException {
//Create a NIO transport instance
final TCPNIOTransport transport = TCPNIOTransportBuilder.newInstance().build();
//Create a filter chain
FilterChainBuilder filterChainBuilder = FilterChainBuilder.stateless();
filterChainBuilder.add(new TransportFilter());
filterChainBuilder.add(new ClientFilter());
transport.setProcessor(filterChainBuilder.build());
transport.start();
Connection connection = null;
try {
//Establishing a connection
connection = transport.connect("localhost", 8080).get();
Attribute<Boolean> responseReceived = connection.getAttribute("RESPONSE_RECEIVED");
connection.write(Grizzly.DEFAULT_BUFFER_ALLOCATOR.allocate(String.format("Hello, Grizzly!").getBytes(StandardCharsets.UTF_8)), new CompletionHandler() {
@Override
public void completed(Object result) {
System.out.println("Message sent.");
}
@Override
public void failed(Throwable throwable) {
System.out.println("Message sending failed.");
}
});
//Waiting for a response from the receiving server
synchronized (responseReceived) {
while (!responseReceived.get()) {
try {
responseReceived.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
} finally {
if (connection != null) {
connection.close();
}
transport.shutdownNow();
}
}
}
Server code:
import org.glassfish.grizzly.CompletionHandler;
import org.glassfish.grizzly.Connection;
import org.glassfish.grizzly.Grizzly;
import org.glassfish.grizzly.asyncqueue.WritableMessage;
import org.glassfish.grizzly.http.server.*;
import org.glassfish.grizzly.http.util.Header;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.atomic.AtomicBoolean;
public class Server {
public static void main(String[] args) throws IOException {
HttpServer httpServer = HttpServer.createSimpleServer();
httpServer.getServerConfiguration().addHttpHandler(new HttpHandler() {
@Override
public void service(Request request, Response response) throws Exception {
AtomicBoolean responseSent = new AtomicBoolean(false);
response.suspend();
//Process requests sent by clients
request.getContent().addCompletionHandler(new CompletionHandler() {
@Override
public void cancelled() {
if (responseSent.compareAndSet(false, true)) {
response.setStatus(500, "Request cancelled");
response.resume();
}
}
@Override
public void failed(Throwable throwable) {
if (responseSent.compareAndSet(false, true)) {
response.setStatus(500, "Internal server error");
response.resume();
}
}
@Override
public void completed(Object result) {
if (responseSent.compareAndSet(false, true)) {
String content = new String(((WritableMessage) result).getArray(),
StandardCharsets.UTF_8);
System.out.println("Received message: " + content);
//Send Response
response.setHeader(Header.ContentType, "text/plain");
response.setStatus(200, "OK");
response.getWriter().write("Hello, Client!");
response.resume();
}
}
@Override
public void updated(Object result) {
// You will receive multiple update calls
// Construct WritableMessage instance
// if you are interested in storing the data
// and at the very end of request processing
// you may be interested in the final data Assembly
}
});
}
}, "/");
httpServer.start();
System.in.read();
httpServer.shutdown();
}
}
When using the Grizzly Framework, the following Maven dependencies need to be imported:
<dependency>
<groupId>org.glassfish.grizzly</groupId>
<artifactId>grizzly-http-server</artifactId>
<version>2.4.0</version>
</dependency>
<dependency>
<groupId>org.glassfish.grizzly</groupId>
<artifactId>grizzly-framework</artifactId>
<version>2.4.0</version>
</dependency>
This sample code demonstrates how to use the Grizzly Framework to establish a simple network communication between client and server. The client establishes a connection through the Grizzly Framework and sends a message to the server, which receives the message and sends a response to the client.
