How to implement the WebSocket function in the Javalin framework (Implementing WebSocket Functionality in Javalin Framework)
How to implement the WebSocket function in the Javalin framework
WebSocket is a protocol that implements two -way communication in web applications, allowing the server and client to transmit real -time data through a long -term connection.Implementing the WebSocket function in the Javalin framework can provide applications with the ability to provide instant communication.This article will introduce how to implement the WebSocket function in the Javalin framework and provide a complete programming code and related configuration.
Step 1: Add Javalin framework and dependencies of the WebSocket library
First, add the Javalin framework and the dependencies of the WebSocket library to your Java project.You can use Maven or Gradle to build tools to add the following dependencies to the configuration file of the project:
Maven:
<dependency>
<groupId>io.javalin</groupId>
<artifactId>javalin</artifactId>
<version>4.2.0</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>websocket-api</artifactId>
<version>9.4.35.v20201120</version>
</dependency>
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>websocket-server</artifactId>
<version>9.4.35.v20201120</version>
</dependency>
Gradle:
groovy
implementation 'io.javalin:javalin:4.2.0'
implementation 'org.eclipse.jetty.websocket:websocket-api:9.4.35.v20201120'
implementation 'org.eclipse.jetty.websocket:websocket-server:9.4.35.v20201120'
Step 2: Create a webSocket processing program
In Javalin, a WebSocket processing program can be created by implementing the WebSockethandler interface.The WebSocketHandler interface contains methods to process WebSocket connections and messages.Create a Java class called MywebSockethandler and implement the WebSockethandler interface:
import io.javalin.websocket.WsConnectContext;
import io.javalin.websocket.WsConnectHandler;
import io.javalin.websocket.WsContext;
import io.javalin.websocket.WsMessageContext;
public class MyWebSocketHandler implements WsConnectHandler {
@Override
public void handleConnect(WsConnectContext ctx) {
// Process websocket connection
System.out.println("New WebSocket connection: " + ctx.getSessionId());
}
@Override
public void handleMessage(WsMessageContext ctx) {
// Process WebSocket Message
System.out.println("Received WebSocket message: " + ctx.message());
ctx.send("Server received your message: " + ctx.message());
}
}
In the above code, the handleconnect () method is used to handle the WebSocket connection, and the handlemessage () method is used to process WebSocket messages.You can expand and customize these methods according to actual needs.
Step 3: Configure websocket routing
Configure the WebSocket route through the Routes () method of Javalin.Create a Java class called WebsocketApp, and add the following code to the main () method:
import io.javalin.Javalin;
import io.javalin.websocket.WsHandler;
public class WebSocketApp {
public static void main(String[] args) {
Javalin app = Javalin.create(config -> {
config.enablecorsfrallorigins (); // Allow cross -domain access
}).start(7000);
app.ws("/websocket", new WsHandler() {
@Override
public void configure(JavalinWsConfig wsConfig) {
wsConfig.handler(new MyWebSocketHandler());
}
});
}
}
In the above code, the App.WS () method is used to configure the WebSocket route, and hand over the request with the path to/WebsoCket to MywebSockethandler for processing.
Step 4: Start the application
Finally, the application is activated in the main () method.Run the main () method in the WebSocketApp class, the Javalin application will start on the port number 7000 and wait for the websock to connect.
The complete code is as follows:
// WebSocketApp.java
import io.javalin.Javalin;
import io.javalin.websocket.WsHandler;
public class WebSocketApp {
public static void main(String[] args) {
Javalin app = Javalin.create(config -> {
config.enableCorsForAllOrigins();
}).start(7000);
app.ws("/websocket", new WsHandler() {
@Override
public void configure(JavalinWsConfig wsConfig) {
wsConfig.handler(new MyWebSocketHandler());
}
});
}
}
// MyWebSocketHandler.java
import io.javalin.websocket.WsConnectContext;
import io.javalin.websocket.WsConnectHandler;
import io.javalin.websocket.WsContext;
import io.javalin.websocket.WsMessageContext;
public class MyWebSocketHandler implements WsConnectHandler {
@Override
public void handleConnect(WsConnectContext ctx) {
System.out.println("New WebSocket connection: " + ctx.getSessionId());
}
@Override
public void handleMessage(WsMessageContext ctx) {
System.out.println("Received WebSocket message: " + ctx.message());
ctx.send("Server received your message: " + ctx.message());
}
}
Through the above steps, you have successfully implemented the WebSocket function in the Javalin framework.Now you can send and receive messages through the WebSocket connection to realize real -time communication.
