Java实现接收摄像头视频流推给前端播放

可以使用JavaCV库来实现接收摄像头视频流，并使用WebSocket将视频流推送给前端进行播放。具体实现可以参考以下代码：

import org.bytedeco.javacv.*;
import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;

public class CameraWebSocketServer extends WebSocketServer {

    private static final int WEBSOCKET_PORT = 8888;
    private static final int CAMERA_INDEX = 0;

    private static FrameGrabber grabber;
    private static OpenCVFrameConverter.ToIplImage converter;
    private static ByteArrayOutputStream outputStream;

    public CameraWebSocketServer() {
        super(new InetSocketAddress(WEBSOCKET_PORT));
    }

    @Override
    public void onOpen(WebSocket webSocket, ClientHandshake clientHandshake) {
        System.out.println("WebSocket opened");
    }

    @Override
    public void onClose(WebSocket webSocket, int i, String s, boolean b) {
        System.out.println("WebSocket closed");
    }

    @Override
    public void onMessage(WebSocket webSocket, ByteBuffer byteBuffer) {
        // do nothing
    }

    @Override
    public void onError(WebSocket webSocket, Exception e) {
        System.out.println("WebSocket error: " + e.getMessage());
    }

    @Override
    public void onStart() {
        System.out.println("WebSocket server started");

        // initialize camera grabber and converter
        grabber = new OpenCVFrameGrabber(CAMERA_INDEX);
        converter = new OpenCVFrameConverter.ToIplImage();

        try {
            grabber.start();
        } catch (FrameGrabber.Exception e) {
            System.out.println("Failed to start camera grabber: " + e.getMessage());
            System.exit(1);
        }

        // start sending video frames to WebSocket clients
        new Thread(() -> {
            while (true) {
                try {
                    // grab a frame from the camera
                    Frame frame = grabber.grab();

                    // convert the frame to an IplImage
                    IplImage image = converter.convert(frame);

                    // encode the image to JPEG format
                    outputStream = new ByteArrayOutputStream();
                    Java2DFrameUtils.toMat(frame).encode(".jpg", outputStream);

                    // send the image data to all WebSocket clients
                    broadcast(outputStream.toByteArray());
                } catch (FrameGrabber.Exception | IOException e) {
                    System.out.println("Failed to grab camera frame: " + e.getMessage());
                }
            }
        }).start();
    }

    public static void main(String[] args) {
        new CameraWebSocketServer().start();
    }
}

这段代码实现了一个WebSocket服务器，可以接收前端的连接并推送摄像头视频流。在启动WebSocket服务器之前，需要先安装JavaCV库和Java-WebSocket库。