WebSocket集成

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.java_websocket.WebSocket;

public class WsPool {
    private static final Map<WebSocket, String> wsUserMap = new HashMap<WebSocket, String>();

    /**
     * 通过websocket连接获取其对应的用户
     *
     * @param conn
     * @return
     */
    public static String getUserByWs(WebSocket conn) {
        return wsUserMap.get(conn);
    }

    /**
     * 根据userName获取WebSocket,这是一个list,此处取第一个
     * 因为有可能多个websocket对应一个userName（但一般是只有一个，因为在close方法中，我们将失效的websocket连接去除了）
     *
     * @param user
     */
    public static WebSocket getWsByUser(String userName) {
        Set<WebSocket> keySet = wsUserMap.keySet();
        synchronized (keySet) {
            for (WebSocket conn : keySet) {
                String cuser = wsUserMap.get(conn);
                if (cuser.equals(userName)) {
                    return conn;
                }
            }
        }
        return null;
    }

    /**
     * 向连接池中添加连接
     *
     * @param inbound
     */
    public static void addUser(String userName, WebSocket conn) {
        wsUserMap.put(conn, userName); // 添加连接
    }

    /**
     * 获取所有连接池中的用户，因为set是不允许重复的，所以可以得到无重复的user数组
     *
     * @return
     */
    public static Collection<String> getOnlineUser() {
        List<String> setUsers = new ArrayList<String>();
        Collection<String> setUser = wsUserMap.values();
        for (String u : setUser) {
            setUsers.add(u);
        }
        return setUsers;
    }

    /**
     * 移除连接池中的连接
     *
     * @param inbound
     */
    public static boolean removeUser(WebSocket conn) {
        if (wsUserMap.containsKey(conn)) {
            wsUserMap.remove(conn); // 移除连接
            return true;
        } else {
            return false;
        }
    }

    /**
     * 向特定的用户发送数据
     *
     * @param user
     * @param message
     */
    public static void sendMessageToUser(WebSocket conn, String message) {
        if (null != conn && null != wsUserMap.get(conn)) {
            conn.send(message);
        }
    }

    /**
     * 向所有的用户发送消息
     *
     * @param message
     */
    public static void sendMessageToAll(String message) {
        Set<WebSocket> keySet = wsUserMap.keySet();
        synchronized (keySet) {
            for (WebSocket conn : keySet) {
                String user = wsUserMap.get(conn);
                if (user != null) {
                    conn.send(message);
                }
            }
        }
    }

}

解释：这个是核心类 用于存放和移除查找ws用户信息的

import java.net.InetSocketAddress;

import org.java_websocket.WebSocket;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;

public class WsServer extends WebSocketServer {

    public WsServer(int port) {
        super(new InetSocketAddress(port));
    }

    public WsServer(InetSocketAddress address) {
        super(address);
    }

    @Override
    public void onOpen(WebSocket conn, ClientHandshake handshake) {
        // ws连接的时候触发的代码，onOpen中我们不做任何操作

    }

    @Override
    public void onClose(WebSocket conn, int code, String reason, boolean remote) {
        //断开连接时候触发代码
        userLeave(conn);
    }

    @Override
    public void onMessage(WebSocket conn, String message) {
        if(null != message &&message.startsWith("online")){
            String userName=message.replaceFirst("online", "");//用户名
            userJoin(conn,userName);//用户加入
        }else if(null != message && message.startsWith("offline")){
            userLeave(conn);
        }

    }

    @Override
    public void onError(WebSocket conn, Exception ex) {
        //错误时候触发的代码
        ex.printStackTrace();
    }
    /**
     * 去除掉失效的websocket链接
     * @param conn
     */
    private void userLeave(WebSocket conn){
        WsPool.removeUser(conn);
    }
    /**
     * 将websocket加入用户池
     * @param conn
     * @param userName
     */
    private void userJoin(WebSocket conn,String userName){
        WsPool.addUser(userName, conn);
    }

}

解释：这个是登陆后与前端信息交互的

import org.java_websocket.WebSocketImpl;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;

@Component
public class WsStart {
    @PostConstruct
    public void startWebSocket() {
        WebSocketImpl.DEBUG = false;
        new WsServer(10887).start();
    }
}

解释：项目启动时开启服务

WsPool.sendMessageToUser(
        WsPool.getWsByUser(
                (String)SecurityUtils.getSubject().getPrincipal())
        , "msg");

解释：服务器指定push

var websocket = '';
var last_health;
var health_timeout = 10;
var username = $('#principal').val();
$(function(){
    if(!username){
        return;
    }
    initWs();
})
var initWs = function() {
    if(!$('#principal').val()){
        return;
    }
    if (window.WebSocket) {
        websocket = new WebSocket(
            encodeURI('ws://' + document.domain + ':10887'));
        websocket.onopen = function() {
            $('.cover').html('已连接</br>'+$('.cover').html());
            websocket.send("online"+username);
            heartbeat_timer = setInterval(function() {
                keepalive(websocket)
            }, 60000);
        };
        websocket.onerror = function() {
            $('.cover').html('连接发生错误<br/>'+$('.cover').html());
        };
        websocket.onclose = function() {
            $('.cover').html('已经断开连接</br>'+$('.cover').html());
            initWs();
        };
        // 消息接收
        websocket.onmessage = function(message) {
            $('.cover').html(message.data+'<br/>'+$('.cover').html())
        };
    } else {
        $('.cover').html('该浏览器不支持<br/>'+$('.cover').html());
    }
}

// 心跳包
function keepalive(ws) {
    var time = new Date();
    if (last_health != -1 && (time.getTime() - last_health > health_timeout)) {

        // ws.close();
    } else {
        if (ws.bufferedAmount == 0) {
            ws.send('~HC~');
        }
    }
}

function wslogout(){
    websocket.send("offline"+username);
}

解释：与服务器交互时的Js

<dependency>
    <groupId>org.java-websocket</groupId>
    <artifactId>Java-WebSocket</artifactId>
    <version>1.3.0</version>
</dependency>

解释：引入jar文件

如果还有什么不全的请留言指出。谢谢！