java WebSocket客户端断线重连的实现方法

前言

在工作中是否会遇到实用websocket客户端连接服务端的时候，网络波动，服务端断连的情况。会导致客户端被动断开连接。为了解决这个问题，需要对被动断开连接的情况进行捕获，并重新创建连接。这篇文章主要是提供可以直接使用的断线重连websocket客户端代码。

maven依赖

        <dependency>
            <groupid>org.projectlombok</groupid>
            <artifactid>lombok</artifactid>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupid>cn.hutool</groupid>
            <artifactid>hutool-all</artifactid>
            <version>5.5.2</version>
        </dependency>
        <dependency>
            <groupid>org.java-websocket</groupid>
            <artifactid>java-websocket</artifactid>
            <version>1.5.1</version>
        </dependency>

代码

不废话，上代码。

package ai.guiji.csdn.ws.client;
 
import cn.hutool.core.thread.threadutil;
import cn.hutool.core.util.strutil;
import lombok.extern.slf4j.slf4j;
import org.java_websocket.websocket;
import org.java_websocket.client.websocketclient;
import org.java_websocket.framing.framedata;
import org.java_websocket.handshake.serverhandshake;
 
import javax.net.ssl.*;
import java.net.socket;
import java.net.uri;
import java.nio.bytebuffer;
import java.security.cert.certificateexception;
import java.security.cert.x509certificate;
import java.util.concurrent.timeunit;
import java.util.concurrent.atomic.atomicboolean;
import java.util.concurrent.atomic.atomicinteger;
import java.util.function.consumer;
 
/** @author huyi @date 2021/10/15 20:03 @description: 重连websocket客户端 */
@slf4j
public class reconnectwebsocketclient {
  /** 字符串消息回调 */
  private consumer<string> msgstr;
  /** 字节流消息回调 */
  private consumer<bytebuffer> msgbyte;
  /** 异常回调 */
  private consumer<exception> error;
  /** 连接标识 */
  private string key;
  /** ws服务端连接 */
  private uri serveruri;
  /** 尝试重连标识 */
  private atomicboolean tryreconnect;
  /** 需要ping标识 */
  private atomicboolean needping;
  /** websocket连接实体 */
  private websocketclient websocketclient;
  /** 重连次数 */
  private atomicinteger reconnecttimes;
  /** 连接结束标识 */
  private atomicboolean end;
  /** 连接后初始发送报文，这里也可以不需要，如果服务端主动断开连接，重连后可以继续推送报文的话。 */
  private string initreconnectreq;
  /** 结束回调 */
  private consumer<string> endconsumer;
 
  public reconnectwebsocketclient(
      uri serveruri,
      string key,
      consumer<string> msgstr,
      consumer<bytebuffer> msgbyte,
      consumer<exception> error) {
    this.msgstr = msgstr;
    this.msgbyte = msgbyte;
    this.error = error;
    this.key = key;
    this.serveruri = serveruri;
    this.tryreconnect = new atomicboolean(false);
    this.needping = new atomicboolean(true);
    this.reconnecttimes = new atomicinteger(0);
    this.end = new atomicboolean(false);
    this.endconsumer = this::close;
    init();
  }
 
  /** 初始化连接 */
  public void init() {
    // 创建连接
    createwebsocketclient();
    // ping线程
    circleping();
  }
 
  private void needreconnect() throws exception {
    threadutil.sleep(10, timeunit.seconds);
    int cul = reconnecttimes.incrementandget();
    if (cul > 3) {
      close("real stop");
      throw new exception("服务端断连，3次重连均失败");
    }
    log.warn("[{}]第[{}]次断开重连", key, cul);
    if (tryreconnect.get()) {
      log.error("[{}]第[{}]次断开重连结果 -> 连接正在重连，本次重连请求放弃", key, cul);
      needreconnect();
      return;
    }
    try {
      tryreconnect.set(true);
 
      if (websocketclient.isopen()) {
        log.warn("[{}]第[{}]次断开重连，关闭旧连接", key, cul);
        websocketclient.closeconnection(2, "reconnect stop");
      }
      websocketclient = null;
      createwebsocketclient();
      connect();
      if (strutil.hasblank(initreconnectreq)) {
        send(initreconnectreq);
      }
    } catch (exception exception) {
      log.error("[{}]第[{}]次断开重连结果 -> 连接正在重连，重连异常:[{}]", key, cul, exception.getmessage());
      needreconnect();
    } finally {
      tryreconnect.set(false);
    }
  }
 
  private void createwebsocketclient() {
    websocketclient =
        new websocketclient(serveruri) {
          @override
          public void onopen(serverhandshake serverhandshake) {
            log.info("[{}]reconnectwebsocketclient [onopen]连接成功{}", key, getremotesocketaddress());
            tryreconnect.set(false);
          }
 
          @override
          public void onmessage(string text) {
            log.info("[{}]reconnectwebsocketclient [onmessage]接收到服务端数据：text={}", key, text);
            msgstr.accept(text);
          }
 
          @override
          public void onmessage(bytebuffer bytes) {
            log.info("[{}]reconnectwebsocketclient [onmessage]接收到服务端数据：bytes={}", key, bytes);
            msgbyte.accept(bytes);
          }
 
          @override
          public void onwebsocketpong(websocket conn, framedata f) {
            log.info(
                "[{}]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode={}",
                key,
                f.getopcode());
          }
 
          @override
          public void onclose(int i, string s, boolean b) {
            log.info("[{}]reconnectwebsocketclient [onclose]关闭，s={}，b={}", key, s, b);
            if (strutil.hasblank(s) || s.contains("https")) {
              if (end.get()) {
                return;
              }
              try {
                needreconnect();
              } catch (exception exception) {
                endconsumer.accept("reconnect error");
                error.accept(exception);
              }
            }
          }
 
          @override
          public void onerror(exception e) {
            log.info("[{}]reconnectwebsocketclient [onerror]异常，e={}", key, e);
            endconsumer.accept("error close");
            error.accept(e);
          }
        };
    if (serveruri.tostring().contains("wss://")) {
      trustallhosts(websocketclient);
    }
  }
 
  public void circleping() {
    new thread(
            () -> {
              while (needping.get()) {
                if (websocketclient.isopen()) {
                  websocketclient.sendping();
                }
                threadutil.sleep(5, timeunit.seconds);
              }
              log.warn("[{}]ping循环关闭", key);
            })
        .start();
  }
 
  /**
   * 连接
   *
   * @throws exception 异常
   */
  public void connect() throws exception {
    websocketclient.connectblocking(10, timeunit.seconds);
  }
 
  /**
   * 发送
   *
   * @param msg 消息
   * @throws exception 异常
   */
  public void send(string msg) throws exception {
    this.initreconnectreq = msg;
    if (websocketclient.isopen()) {
      websocketclient.send(msg);
    }
  }
 
  /**
   * 关闭
   *
   * @param msg 关闭消息
   */
  public void close(string msg) {
    needping.set(false);
    end.set(true);
    if (websocketclient != null) {
      websocketclient.closeconnection(3, msg);
    }
  }
 
  /**
   * 忽略证书
   *
   * @param client
   */
  public void trustallhosts(websocketclient client) {
    trustmanager[] trustallcerts =
        new trustmanager[] {
          new x509extendedtrustmanager() {
 
            @override
            public void checkclienttrusted(
                x509certificate[] x509certificates, string s, socket socket)
                throws certificateexception {}
 
            @override
            public void checkservertrusted(
                x509certificate[] x509certificates, string s, socket socket)
                throws certificateexception {}
 
            @override
            public void checkclienttrusted(
                x509certificate[] x509certificates, string s, sslengine sslengine)
                throws certificateexception {}
 
            @override
            public void checkservertrusted(
                x509certificate[] x509certificates, string s, sslengine sslengine)
                throws certificateexception {}
 
            @override
            public void checkclienttrusted(x509certificate[] x509certificates, string s)
                throws certificateexception {}
 
            @override
            public void checkservertrusted(x509certificate[] x509certificates, string s)
                throws certificateexception {}
 
            @override
            public x509certificate[] getacceptedissuers() {
              return null;
            }
          }
        };
 
    try {
      sslcontext ssl = sslcontext.getinstance("ssl");
      ssl.init(null, trustallcerts, new java.security.securerandom());
      sslsocketfactory socketfactory = ssl.getsocketfactory();
      client.setsocketfactory(socketfactory);
    } catch (exception e) {
      log.error("reconnectwebsocketclient trustallhosts 异常，e={0}", e);
    }
  }
}

代码说明：

1、参数的重连次数可以配置。

2、增加异步pingpong线程，一旦结束连接会自动关闭。

3、对字符串、字节流、异常都有回调措施。

测试代码方法

  public static void main(string[] args) throws exception {
    reconnectwebsocketclient client =
        new reconnectwebsocketclient(
            new uri(string.format("wss://192.168.1.77:24009")),
            "test",
            // 字符串消息处理
            msg -> {
              // todo 字符串消息处理
              system.out.println("字符串消息:" + msg);
            },
            null,
            // 异常回调
            error -> {
              // todo 字符串消息处理
              system.out.println("异常:" + error.getmessage());
            });
    client.connect();
    client.send("haha");
  }

验证结果

16:08:54.468 [websocketconnectreadthread-12] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onopen]连接成功/192.168.1.77:24009
16:08:54.475 [websocketconnectreadthread-12] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onmessage]接收到服务端数据：text=connect success from tcp4:192.168.6.63:11018!
字符串消息:connect success from tcp4:192.168.6.63:11018!
16:08:56.080 [websocketconnectreadthread-12] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onclose]关闭，s=，b=true
16:09:06.097 [websocketconnectreadthread-12] warn ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]第[1]次断开重连
16:09:06.150 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onopen]连接成功/192.168.1.77:24009
16:09:06.150 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onmessage]接收到服务端数据：text=connect success from tcp4:192.168.6.63:11038!
字符串消息:connect success from tcp4:192.168.6.63:11038!
16:09:09.369 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:14.370 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:19.371 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:24.379 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:29.382 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:34.398 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:39.402 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:44.404 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:49.415 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:54.429 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:09:59.437 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:10:04.449 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:10:06.154 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:10:09.455 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:10:14.462 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:10:19.468 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onwebsocketpong]接收到服务端数据：opcode=pong
16:10:19.644 [websocketconnectreadthread-16] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onclose]关闭，s=，b=true
16:10:29.654 [websocketconnectreadthread-16] warn ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]第[2]次断开重连
16:10:31.710 [websocketconnectreadthread-19] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onerror]异常，e={}
java.net.connectexception: connection refused: connect
 at java.net.dualstackplainsocketimpl.connect0(native method)
 at java.net.dualstackplainsocketimpl.socketconnect(dualstackplainsocketimpl.java:79)
 at java.net.abstractplainsocketimpl.doconnect(abstractplainsocketimpl.java:350)
 at java.net.abstractplainsocketimpl.connecttoaddress(abstractplainsocketimpl.java:206)
 at java.net.abstractplainsocketimpl.connect(abstractplainsocketimpl.java:188)
 at java.net.plainsocketimpl.connect(plainsocketimpl.java:172)
 at java.net.sockssocketimpl.connect(sockssocketimpl.java:392)
 at java.net.socket.connect(socket.java:589)
 at sun.security.ssl.sslsocketimpl.connect(sslsocketimpl.java:673)
 at org.java_websocket.client.websocketclient.run(websocketclient.java:461)
 at java.lang.thread.run(thread.java:748)
16:10:31.710 [websocketconnectreadthread-19] info ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]reconnectwebsocketclient [onclose]关闭，s=error close，b=false
异常:connection refused: connect
16:10:34.473 [thread-0] warn ai.guiji.csdn.ws.client.reconnectwebsocketclient - [test]ping循环关闭

这里我才用的是手动关闭服务端方式触发，客户端被动断连情况。重连两次，第二次服务端还未启动导致异常触发。

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