WebSocket + Spring消息推送服务的快速实现

一. 依赖（这里只列举了websocket相关依赖）

<!-- spring webSocket依赖 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-websocket</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-messaging -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- https://mvnrepository.com/artifact/javax.websocket/javax.websocket-api -->
<dependency>
<groupId>javax.websocket</groupId>
<artifactId>javax.websocket-api</artifactId>
<version>1.1</version>
<scope>provided</scope>
</dependency>
<!-- websocket客户端 -->
<dependency>
<groupId>org.glassfish.tyrus.bundles</groupId>
<artifactId>tyrus-standalone-client</artifactId>
<version>1.13</version>
</dependency>

二. WebSocket服务端

2-1. 核心代码

package com.github.websocket.server;

import com.alibaba.fastjson.JSON;
import com.github.CommonConstant;
import com.github.session.SObject;
import com.github.websocket.configuration.HttpSessionConfigurator;
import com.github.websocket.msg.Msg;
import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

import javax.servlet.http.HttpSession;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
* @author : Crab2Died</br>
* @DESC : <p>注解{@link ServerEndpoint}声明websocket 服务端</p></br>
* @date : 2017/5/25  9:43</br>
*/
@ServerEndpoint(value = "/chat", configurator = HttpSessionConfigurator.class)
public class WSServer {

static private Logger logger = Logger.getLogger(WSServer.class);

// 在线人数 线程安全
private static int onlineCount = 0;

// 连接集合 userId => server 键值对 线程安全
static public final ConcurrentMap<String, WSServer> map = new ConcurrentHashMap<>();

// 与某个客户端的连接会话，需要通过它来给客户端发送数据
private Session session;

// 当前会话的httpsession
private HttpSession httpSession;

/**
* @param session websocket连接sesson
* @param config  {@link com.github.websocket.configuration.HttpSessionConfigurator}
* @DESC <p>注解{@link OnOpen} 声明客户端连接进入的方法</p>
*/
@OnOpen
public void onOpen(Session session, EndpointConfig config) {

// 得到httpSession
this.httpSession = (HttpSession) config.getUserProperties().get(HttpSession.class.getName());

// 获取session对象 SObject(这个就是java web登入后的保存的session对象，此处为用户信息，包含了userId)
SObject user = (SObject) this.httpSession.getAttribute(CommonConstant.USER_LOGIN_SESSION);

this.session = session;

// 将连接session对象存入map
map.put(user.getUid(), this);

// 连接数+1
addOnlineCount();

logger.info("有新的连接，当前连接数为：" + getOnlineCount());
}

/**
* <p>{@link OnClose} 关闭连接</p>
*/
@OnClose
public void onClose() {

/**
* 获取当前连接信息 {@code CommonConstant.USER_LOGIN_SESSION} 为Http session 名
*/

SObject user = (SObject) this.httpSession.getAttribute(CommonConstant.USER_LOGIN_SESSION);

// 移除连接
map.remove(user.getUid());

// 连接数-1
subOnlineCount();

logger.info("有一连接断开，当前连接数为：" + getOnlineCount());
}

/**
* <p>{@link OnMessage} 消息监听处理方法</p>
*
* @param message 消息对象{@link com.github.websocket.msg.Msg}的JSON对象
* @throws IOException 异常
*/
@OnMessage
public void onMessage(String message) throws IOException {

// 将消息转Msg对象
Msg msg = JSON.parseObject(message, Msg.class);

//TODO 可以对msg做些处理...

// 根据Msg消息对象获取定点发送人的userId
WSServer _client = map.get(msg.getToUid());

// 定点发送
if (StringUtils.isNotEmpty(msg.getToUid())) {
if (null != _client) {
// 是否连接判断
if (_client.session.isOpen())
// 消息发送
_client.session.getBasicRemote().sendText(JSON.toJSONString(msg));
}
}

// 群发
if (StringUtils.isEmpty(msg.getToUid())) {
// 群发已连接用户
for (WSServer client : map.values()) {
client.session.getBasicRemote().sendText(JSON.toJSONString(msg));
}
}

}

/**
* <p>{@link OnError} websocket系统异常处理</p>
*
* @param t 异常
*/
@OnError
public void onError(Throwable t) {
logger.error(t);
t.printStackTrace();
}

/**
* <p>系统主动推送 这是个静态方法在web启动后可在程序的其他合适的地方和时间调用，这就实现了系统的主动推送</p>
*
* @param msg 消息对象{@link com.github.websocket.msg.Msg}的JSON对象
*/
static
public void pushBySys(Msg msg) {

//TODO 也可以实现定点推送

// 群发
for (WSServer client : map.values()) {
try {
client.session.getBasicRemote().sendText(JSON.toJSONString(msg));
} catch (IOException e) {
e.printStackTrace();
}
}
}

// 获取连接数
private static synchronized int getOnlineCount() {
return WSServer.onlineCount;
}

// 增加连接数
private static synchronized void addOnlineCount() {
WSServer.onlineCount++;
}

// 减少连接数
private static synchronized void subOnlineCount() {
WSServer.onlineCount--;
}

}

2-2. HttpSessionConfigurator类

package com.github.websocket.configuration;

import javax.servlet.http.HttpSession;
import javax.websocket.HandshakeResponse;
import javax.websocket.server.HandshakeRequest;
import javax.websocket.server.ServerEndpointConfig;
import javax.websocket.server.ServerEndpointConfig.Configurator;

/**
* @author : Crab2Died</br>
* @DESC : <p>讲http request的session 存入websocket的session内</p></br>
* @date : 2017/5/25  16:08</br>
*/
public class HttpSessionConfigurator extends Configurator {

@Override
public void modifyHandshake(ServerEndpointConfig sec,
HandshakeRequest request, HandshakeResponse response) {

// 获取当前Http连接的session
HttpSession httpSession = (HttpSession) request.getHttpSession();
// 将http session信息注入websocket session
sec.getUserProperties().put(HttpSession.class.getName(), httpSession);
}
}

2-3. Msg消息体

package com.github.websocket.msg;

import java.util.Date;

/**
* @author : Crab2Died</br>
* @DESC : <p>WebSocket消息模型</p></br>
* @date : 2017/5/25  9:43</br>
*/
public class Msg {

// 推送人ID
private String fromUid;

// 定点推送人ID
private String toUid;

// 定点推送单位ID
private String toOrgId;

// 消息体
private String data;

// 推送时间
private Date createDate = new Date();

// 消息状态
private Integer flag;

public Msg() {

}

public Msg(String fromUid, String toUid, String toOrgId, String data, Date createDate, Integer flag) {
this.fromUid = fromUid;
this.toUid = toUid;
this.toOrgId = toOrgId;
this.data = data;
this.createDate = createDate;
this.flag = flag;
}

public String getFromUid() {
return fromUid;
}

public void setFromUid(String fromUid) {
this.fromUid = fromUid;
}

public String getToUid() {
return toUid;
}

public void setToUid(String toUid) {
this.toUid = toUid;
}

public String getToOrgId() {
return toOrgId;
}

public void setToOrgId(String toOrgId) {
this.toOrgId = toOrgId;
}

public String getData() {
return data;
}

public void setData(String data) {
this.data = data;
}

public Date getCreateDate() {
return createDate;
}

public void setCreateDate(Date createDate) {
this.createDate = createDate;
}

public Integer getFlag() {
return flag;
}

public void setFlag(Integer flag) {
this.flag = flag;
}

@Override
public String toString() {
return "Msg{" +
"fromUid='" + fromUid + '\'' +
", toUid='" + toUid + '\'' +
", toOrgId='" + toOrgId + '\'' +
", data='" + data + '\'' +
", createDate=" + createDate +
", flag=" + flag +
'}';
}
}

三. 客户端（HTML5）

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>WebSocket</title>
<script type="text/javascript">

// 创建websocket实例
var ws = new WebSocket("ws://localhost:8080/chat");
/*
*监听三种状态的变化js会回调
*/
ws.onopen = function(message) {
// 连接回调
};
ws.onclose = function(message) {
// 断开连接回调
};
ws.onmessage = function(message) {
// 消息监听
showMessage(message.data);
};
//监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
window.onbeforeunload = function() {
ws.close();
};
//关闭连接
function closeWebSocket() {
ws.close();
}
//发送消息
function send() {

var input = document.getElementById("msg");
var text = input.value;

// 消息体JSON 对象 对应JAVA 的 Msg对象
var data = {
// 定点发送给其他用户的userId
toUid : "3d535429-5fcb-4490-bcf7-96fd84bb17b6",
data : text
}

ws.send(JSON.stringify(data));
input.value = "";
}
function showMessage(message) {
var text = document.createTextNode(JSON.parse(message).data);
var br = document.createElement("br")
var div = document.getElementById("showChatMessage");
div.appendChild(text);
div.appendChild(br);
}
</script>
</head>
<body>
<div>
style="width: 600px; height: 240px; overflow-y: auto; border: 1px solid #333;"
id="show">
<div id="showChatMessage"></div>
<input type="text" size="80" id="msg" name="msg" placeholder="输入聊天内容" />
<input type="button" value="发送" id="sendBn" name="sendBn" onclick="send()">
</div>
</body>
</html>