java WebSocket实现聊天消息推送功能

本文实例为大家分享了java WebSocket实现聊天消息推送功能的具体代码，供大家参考，具体内容如下

环境：

JDK.1.7.0_51

apache-tomcat-7.0.53

java jar包：tomcat-coyote.jar、tomcat-juli.jar、websocket-api.jar

ChatAnnotation消息发送类：

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
 
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
 
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
 
import com.util.HTMLFilter; 
 
/**
 * WebSocket 消息推送服务类
 * @author 胡汉三
 *
 * 2014-11-18 下午7:53:13
 */
@ServerEndpoint(value = "/websocket/chat")
public class ChatAnnotation {
 
  private static final Log log = LogFactory.getLog(ChatAnnotation.class);
 
  private static final String GUEST_PREFIX = "Guest";
  private static final AtomicInteger connectionIds = new AtomicInteger(0);
  private static final Map connections = new HashMap();
 
  private final String nickname;
  private Session session;
 
  public ChatAnnotation() {
    nickname = GUEST_PREFIX + connectionIds.getAndIncrement();
  }
 
 
  @OnOpen
  public void start(Session session) {
    this.session = session;
    connections.put(nickname, this); 
    String message = String.format("* %s %s", nickname, "has joined.");
    broadcast(message);
  }
 
 
  @OnClose
  public void end() {
    connections.remove(this);
    String message = String.format("* %s %s",
        nickname, "has disconnected.");
    broadcast(message);
  }
 
 
  /**
   * 消息发送触发方法
   * @param message
   */
  @OnMessage
  public void incoming(String message) {
    // Never trust the client
    String filteredMessage = String.format("%s: %s",
        nickname, HTMLFilter.filter(message.toString()));
    broadcast(filteredMessage);
  }
 
  @OnError
  public void onError(Throwable t) throws Throwable {
    log.error("Chat Error: " + t.toString(), t);
  }
 
  /**
   * 消息发送方法
   * @param msg
   */
  private static void broadcast(String msg) {
   if(msg.indexOf("Guest0")!=-1){
   sendUser(msg);
   } else{
   sendAll(msg);
   }
  } 
  
  /**
   * 向所有用户发送
   * @param msg
   */
  public static void sendAll(String msg){
   for (String key : connections.keySet()) {
     ChatAnnotation client = null ;
      try {
       client = (ChatAnnotation) connections.get(key);
        synchronized (client) {
          client.session.getBasicRemote().sendText(msg);
        }
      } catch (IOException e) { 
        log.debug("Chat Error: Failed to send message to client", e);
        connections.remove(client);
        try {
          client.session.close();
        } catch (IOException e1) {
          // Ignore
        }
        String message = String.format("* %s %s",
            client.nickname, "has been disconnected.");
        broadcast(message);
      }
    }
  }
  
  /**
   * 向指定用户发送消息 
   * @param msg
   */
  public static void sendUser(String msg){
   ChatAnnotation c = (ChatAnnotation)connections.get("Guest0");
 try {
  c.session.getBasicRemote().sendText(msg);
 } catch (IOException e) {
  log.debug("Chat Error: Failed to send message to client", e);
      connections.remove(c);
      try {
        c.session.close();
      } catch (IOException e1) {
        // Ignore
      }
      String message = String.format("* %s %s",
          c.nickname, "has been disconnected.");
      broadcast(message); 
 } 
  }
}

HTMLFilter工具类：

/**
 * HTML 工具类 
 *
 * @author 胡汉三
 */
public final class HTMLFilter {
  public static String filter(String message) {
    if (message == null)
      return (null);
    char content[] = new char[message.length()];
    message.getChars(0, message.length(), content, 0);
    StringBuilder result = new StringBuilder(content.length + 50);
    for (int i = 0; i < content.length; i++) {
      switch (content[i]) {
      case '<':
        result.append("<");
        break;
      case '>':
        result.append(">");
        break;
      case '&':
        result.append("&");
        break;
      case '"':
        result.append(""");
        break;
      default:
        result.append(content[i]);
      }
    }
    return (result.toString());
  }
}

页面：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 



  
  
  


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可指定发送给某个用户，也可全部发送，详情见ChatAnnotation类的broadcast方法。
程序发布时记得删除tomcat-coyote.jar、tomcat-juli.jar、websocket-api.jar这三个jar包在启动Tomcat。

程序截图，Guest0用户发送信息的信息，在后台进行了判断只发送给自己：

Guest1：

Guest2：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。