okhttp 有websocket吗

是的，OkHttp支持WebSocket。从OkHttp版本3.5开始，它就内置了WebSocket API，可以用来进行WebSocket通信。您可以使用OkHttp的WebSocket API来建立WebSocket连接、发送消息和接收消息。以下是一个使用OkHttp WebSocket的示例代码：

OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
        .url("ws://echo.websocket.org")
        .build();
WebSocket webSocket = client.newWebSocket(request, new WebSocketListener() {
    @Override
    public void onOpen(WebSocket webSocket, Response response) {
        // WebSocket连接成功
        webSocket.send("Hello, WebSocket!");
    }

    @Override
    public void onMessage(WebSocket webSocket, String text) {
        // 收到消息
        System.out.println("Received message: " + text);
    }

    @Override
    public void onClosing(WebSocket webSocket, int code, String reason) {
        // WebSocket关闭中
        System.out.println("WebSocket closing: " + reason);
    }

    @Override
    public void onClosed(WebSocket webSocket, int code, String reason) {
        // WebSocket已关闭
        System.out.println("WebSocket closed: " + reason);
    }

    @Override
    public void onFailure(WebSocket webSocket, Throwable t, Response response) {
        // WebSocket失败
        System.out.println("WebSocket failure: " + t.getMessage());
    }
});

在这个示例代码中，我们使用OkHttp建立了一个WebSocket连接到"ws://echo.websocket.org"地址，然后发送了一条消息"Hello, WebSocket!"。当WebSocket收到消息时，会通过onMessage()方法回调通知我们。当WebSocket关闭时，会通过onClosing()和onClosed()方法回调通知我们。当WebSocket失败时，会通过onFailure()方法回调通知我们。