Write websocket client pressure test script in Java

For Java developers, it is relatively easy to write websocket client stress test scripts in Java. Here is an example of a Java-based websocket client stress test script for your reference.
import java.net.URI;
import java.util.concurrent.CountDownLatch;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;

public class WebSocketClientTest {

    public static void main( String[] args ) throws InterruptedException {
        int count = 100;
        String serverUrl = "wss://example.com/ws";

        CountDownLatch latch = new CountDownLatch( count );
        for (int i = 0; i < count; i++) {
            WebSocketClient client = new WebSocketClient( new URI( serverUrl ) ) {
                @Override
                public void onOpen( ServerHandshake handshake ) {
                    System.out.println( "Opened: " + handshake );
                }

                @Override
                public void onMessage( String message ) {
                    System.out.println( "Received: " + message );
                }

                @Override
                public void onClose( int code, String reason, boolean remote ) {
                    System.out.println( "Closed: " + reason );
                    latch.countDown();
                }

                @Override
                public void onError( Exception ex ) {
                    System.out.println( "Exception: " + ex.getMessage() );
                    latch.countDown();
                }
            };
            client.connect();
        }

        latch.await();
    }
}
```

In the above example, the `org.java_websocket` library is used to implement the websocket client. The library can be introduced through construction tools such as Maven, or can be downloaded from the official website and manually introduced. The `org.java_websocket` library provides the `WebSocketClient` class to implement the WebSocket client, and this class provides four callback methods, namely `onOpen`, `onMessage`, `onClose` and `onError`, we can here Do some logic processing in the four callback methods.

In the example, we use the `CountDownLatch` class to control thread synchronization and ensure that the program ends when all websocket connections are closed. `CountDownLatch` needs to specify the value of the counter when it is created, and then the value of the counter can be reduced by the `countDown` method, and the current thread can be blocked by the `await` method until the value of the counter is 0.

Use the `for` loop to simulate creating multiple websocket connections for pressure testing. When all websocket connections are successfully connected, the program will block at `latch.await()`, until all connections are closed, the program will Finish.

The above is a simple example of a WebSocket client stress test script implemented in Java, which can be used as a reference to write your own stress test script.