Java与JavaScript交互：基于WebSocket的示例

原创 r囧r小猫 2024-12-05 14:48 8阅读 0赞

Java和JavaScript之间的交互可以通过WebSocket（一种在单个TCP连接上进行全双工通信的协议）来实现。以下是一个基于WebSocket的Java服务器端示例，以及一个简单的JavaScript客户端示例。

**Java服务器端（ServerSide.java）：**

```java
import java.io.IOException;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;

@ServerEndpoint("/websocket")
public class ServerSide {

@OnMessage
    public String onMessage(String message) {
        System.out.println("Received: " + message);
        return "Message processed.";
    }

@OnClose
    public void onClose(Session session) {
        System.out.println("Connection closed.");
    }

@OnError
    public void onError(Throwable error) {
        System.err.println("Error occurred: " + error.getMessage());
        error.printStackTrace();
    }
}
```

**JavaScript客户端（ClientSide.js）：**

```javascript
// JavaScript Client

// WebSocket URL (replace with your server's endpoint)
const websocketURL = 'ws://your.server.com/websocket';

// WebSocket connection
let socket;

// Connect to the server
function connect() {
    if (!socket) {
        socket = new WebSocket(websocketURL);
        
        // Add event listeners for various events
        socket.addEventListener('open', handleOpen));
        socket.addEventListener('message', handleMessage));
        socket.addEventListener('close', handleClose));
    }
}

// Event handling functions
function handleOpen(event) {
    console.log('WebSocket opened.');
}

function handleMessage(event) {
    const message = event.data;
    console.log('Received: ' + message);
    // Send a response back to the server
    sendResponse(message, 'Processed.');
}

function handleClose(event) {
    console.log('WebSocket closed by server.');
    socket.close();
    socket = null;
}

// Function to send a message to the server
function sendMessage(message) {
    if (socket) {
        socket.send(message);
        console.log('Message sent to server: ' + message);
    }
}

// Function to handle response from the server
function handleResponse(response) {
    // Do something with the response, like display it or process it further
    console.log('Received response from server: ' + response);
}

// Function to send a response back to the server
function sendResponse(message, status) {
    sendMessage(JSON.stringify({ message: message, status: status }))));
}

// Call connect() function to establish the connection with the server
connect();
```

在这个示例中，服务器端（Java）通过WebSocket处理来自客户端的消息。客户端（JavaScript）可以通过连接到特定的WebSocket URL来与服务器交互。

请注意替换`websocketURL`和`your.server.com`为你的实际WebSocket URL和服务器地址。