A Practical Java WebSocket Client Wrapper: Design, Features, and Demo

Overview

The WebSocketFunClient class is a lightweight wrapper around org.java_websocket.client.WebSocketClient. It is designed for rapid WebSocket protocol testing and performance measurement by providing convenient factory methods, connection‑retry logic, logging, and a bounded message buffer.

Key Features

Factory methods getInstance(String url) and getInstance(String url, String cname) create client instances with a unique name (cname) for easier identification in logs.

Automatic connection retry: after connect() the client polls ReadyState.OPEN and retries up to SocketConstant.MAX_WATI_TIMES with a pause of SocketConstant.WAIT_INTERVAL milliseconds.

Thread‑safe bounded message buffer: a LinkedList<String> stores the most recent messages, capped by SocketConstant.MAX_MSG_SIZE. Older entries are discarded automatically.

Utility send overloads for raw strings, custom Charset, JSON objects ( com.alibaba.fastjson.JSONObject), and custom beans ( AbstractBean).

Static collection Vector<WebSocketFunClient> socketClients tracks all created instances, enabling bulk shutdown via closeAll().

Configuration Constants

The companion class SocketConstant (not reproduced here) defines static values used throughout the client: MAX_MSG_SIZE – maximum number of messages retained in the buffer. MAX_WATI_TIMES – maximum number of connection‑retry attempts. WAIT_INTERVAL – sleep interval (ms) between retry attempts.

Core Implementation Details

Important overridden callbacks: onOpen(ServerHandshake handshakedata) – logs handshake fields. onMessage(String message) – stores the message in the bounded buffer and logs it. onClose(int code, String reason, boolean remote) – logs closure details. onError(Exception e) – logs exceptions.

Additional methods: saveMsg(String msg) – synchronized insertion into the bounded buffer. close() – logs a warning, closes the socket, and removes the instance from socketClients. closeAll() – iterates over socketClients, closes any open connections, clears the collection, and logs the operation. clone() – creates a new client with the same URL but a different random suffix for cname, useful for concurrent performance tests.

Usage Example

public static void main(String[] args) {
    WebSocketFunClient client = WebSocketFunClient.getInstance("ws://127.0.0.1:8080/ws/fun");
    client.connect();
    client.send("FunTester");
    // wait for messages or perform further actions
    Thread.sleep(10000);
    client.close();
}

Sample Console Output

INFO  FunTesterkgbn 正在建立socket连接...
INFO  握手信息key: Connection ,value: upgrade
INFO  握手信息key: Date ,value: Mon, 30 Nov 2020 09:16:30 GMT
INFO  握手信息key: Sec-WebSocket-Accept ,value: yQj8IZx/STCzhcWY0ovQ98hxI8o=
INFO  握手信息key: Upgrade ,value: websocket
INFO  FunTesterkgbn收到: 世界喊话器     用户:fun已经上线了!
INFO  FunTesterkgbn 连接成功!
INFO  FunTesterkgbn收到: 世界喊话器     fun:FunTester
WARN  FunTesterkgbn:socket连接关闭!
INFO  FunTesterkgbn socket 连接关闭,URL: ws://127.0.0.1:8080/ws/fun ,code码:1000,原因:,是否由远程服务关闭:false

The source code, including the WebSocketFunClient implementation and the SocketConstant configuration class, is version‑controlled in a Git repository. Clone the repository to obtain the latest updates and integrate the client into your own WebSocket testing framework.