目录
一、介绍
1.两种方式，一种使用tomcat的websocket实现，一种使用spring的websocket
2.tomcat的方式需要tomcat 7.x，JEE7的支持。
3.spring与websocket整合需要spring 4.x，并且使用了socketjs，对不支持websocket的浏览器可以模拟websocket使用
二、方式一：tomcat
使用这种方式无需别的任何配置，只需服务端一个处理类，
服务器端代码
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package
com.Socket;
import
java.io.IOException;
import
java.util.Map;
import
java.util.concurrent.ConcurrentHashMap;
import
javax.websocket.*;
import
javax.websocket.server.PathParam;
import
javax.websocket.server.ServerEndpoint;
import
net.sf.json.JSONObject;
@ServerEndpoint
(
"/websocket/{username}"
)
public
class
WebSocket {
private
static
int
onlineCount =
0
;
private
static
Map<String, WebSocket> clients =
new
ConcurrentHashMap<String, WebSocket>();
private
Session session;
private
String username;
@OnOpen
public
void
onOpen(
@PathParam
(
"username"
) String username, Session session)
throws
IOException {
this
.username = username;
this
.session = session;
addOnlineCount();
clients.put(username,
this
);
System.out.println(
"已连接"
);
}
@OnClose
public
void
onClose()
throws
IOException {
clients.remove(username);
subOnlineCount();
}
@OnMessage
public
void
onMessage(String message)
throws
IOException {
JSONObject jsonTo = JSONObject.fromObject(message);
if
(!jsonTo.get(
"To"
).equals(
"All"
)){
sendMessageTo(
"给一个人"
, jsonTo.get(
"To"
).toString());
}
else
{
sendMessageAll(
"给所有人"
);
}
}
@OnError
public
void
onError(Session session, Throwable error) {
error.printStackTrace();
}
public
void
sendMessageTo(String message, String To)
throws
IOException {
// session.getBasicRemote().sendText(message);
//session.getAsyncRemote().sendText(message);
for
(WebSocket item : clients.values()) {
if
(item.username.equals(To) )
item.session.getAsyncRemote().sendText(message);
}
}
public
void
sendMessageAll(String message)
throws
IOException {
for
(WebSocket item : clients.values()) {
item.session.getAsyncRemote().sendText(message);
}
}
public
static
synchronized
int
getOnlineCount() {
return
onlineCount;
}
public
static
synchronized
void
addOnlineCount() {
WebSocket.onlineCount++;
}
public
static
synchronized
void
subOnlineCount() {
WebSocket.onlineCount--;
}
public
static
synchronized
Map<String, WebSocket> getClients() {
return
clients;
}
}
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客户端js
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var websocket =
null
;
var username = localStorage.getItem(
"name"
);
//判断当前浏览器是否支持WebSocket
if
(
'WebSocket'
in window) {
websocket =
new
WebSocket(
"ws://"
+ document.location.host +
"/WebChat/websocket/"
+ username +
"/"
+ _img);
}
else
{
alert(
'当前浏览器 Not support websocket'
)
}
//连接发生错误的回调方法
websocket.onerror = function() {
setMessageInnerHTML(
"WebSocket连接发生错误"
);
};
//连接成功建立的回调方法
websocket.onopen = function() {
setMessageInnerHTML(
"WebSocket连接成功"
);
}
//接收到消息的回调方法
websocket.onmessage = function(event) {
setMessageInnerHTML(event.data);
}
//连接关闭的回调方法
websocket.onclose = function() {
setMessageInnerHTML(
"WebSocket连接关闭"
);
}
//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() {
closeWebSocket();
}
//关闭WebSocket连接
function closeWebSocket() {
websocket.close();
}
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发送消息只需要使用websocket.send(“发送消息”)，就可以触发服务端的onMessage()方法，当连接时，触发服务器端onOpen()方法，此时也可以调用发送消息的方法去发送消息。关闭websocket时，触发服务器端onclose()方法，此时也可以发送消息，但是不能发送给自己，因为自己的已经关闭了连接，但是可以发送给其他人。
三、方法二：spring整合
WebSocketConfig.java
这个类是配置类，所以需要在spring mvc配置文件中加入对这个类的扫描，第一个addHandler是对正常连接的配置，第二个是如果浏览器不支持websocket，使用socketjs模拟websocket的连接。
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package
com.websocket;
import
org.springframework.context.annotation.Bean;
import
org.springframework.context.annotation.Configuration;
import
org.springframework.web.socket.config.annotation.EnableWebSocket;
import
org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import
org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
import
org.springframework.web.socket.handler.TextWebSocketHandler;
@Configuration
@EnableWebSocket
public
class
WebSocketConfig
implements
WebSocketConfigurer {
@Override
public
void
registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(chatMessageHandler(),
"/webSocketServer"
).addInterceptors(
new
ChatHandshakeInterceptor());
registry.addHandler(chatMessageHandler(),
"/sockjs/webSocketServer"
).addInterceptors(
new
ChatHandshakeInterceptor()).withSockJS();
}
@Bean
public
TextWebSocketHandler chatMessageHandler(){
return
new
ChatMessageHandler();
}
}
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ChatHandshakeInterceptor.java
这个类的作用就是在连接成功前和成功后增加一些额外的功能，Constants.java类是一个工具类，两个常量。
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package
com.websocket;
import
java.util.Map;
import
org.apache.shiro.SecurityUtils;
import
org.springframework.http.server.ServerHttpRequest;
import
org.springframework.http.server.ServerHttpResponse;
import
org.springframework.web.socket.WebSocketHandler;
import
org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;
public
class
ChatHandshakeInterceptor
extends
HttpSessionHandshakeInterceptor {
@Override
public
boolean
beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
Map<String, Object> attributes)
throws
Exception {
System.out.println(
"Before Handshake"
);
/*
* if (request instanceof ServletServerHttpRequest) {
* ServletServerHttpRequest servletRequest = (ServletServerHttpRequest)
* request; HttpSession session =
* servletRequest.getServletRequest().getSession(false); if (session !=
* null) { //使用userName区分WebSocketHandler，以便定向发送消息 String userName =
* (String) session.getAttribute(Constants.SESSION_USERNAME); if
* (userName==null) { userName="default-system"; }
* attributes.put(Constants.WEBSOCKET_USERNAME,userName);
*
* } }
*/
//使用userName区分WebSocketHandler，以便定向发送消息(使用shiro获取session,或是使用上面的方式)
String userName = (String) SecurityUtils.getSubject().getSession().getAttribute(Constants.SESSION_USERNAME);
if
(userName ==
null
) {
userName =
"default-system"
;
}
attributes.put(Constants.WEBSOCKET_USERNAME, userName);
return
super
.beforeHandshake(request, response, wsHandler, attributes);
}
@Override
public
void
afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
Exception ex) {
System.out.println(
"After Handshake"
);
super
.afterHandshake(request, response, wsHandler, ex);
}
}
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ChatMessageHandler.java
这个类是对消息的一些处理，比如是发给一个人，还是发给所有人，并且前端连接时触发的一些动作
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package
com.websocket;
import
java.io.IOException;
import
java.util.ArrayList;
import
org.apache.log4j.Logger;
import
org.springframework.web.socket.CloseStatus;
import
org.springframework.web.socket.TextMessage;
import
org.springframework.web.socket.WebSocketSession;
import
org.springframework.web.socket.handler.TextWebSocketHandler;
public
class
ChatMessageHandler
extends
TextWebSocketHandler {
private
static
final
ArrayList<WebSocketSession> users;
// 这个会出现性能问题，最好用Map来存储，key用userid
private
static
Logger logger = Logger.getLogger(ChatMessageHandler.
class
);
static
{
users =
new
ArrayList<WebSocketSession>();
}
/**
* 连接成功时候，会触发UI上onopen方法
*/
@Override
public
void
afterConnectionEstablished(WebSocketSession session)
throws
Exception {
System.out.println(
"connect to the websocket success......"
);
users.add(session);
// 这块会实现自己业务，比如，当用户登录后，会把离线消息推送给用户
// TextMessage returnMessage = new TextMessage("你将收到的离线");
// session.sendMessage(returnMessage);
}
/**
* 在UI在用js调用websocket.send()时候，会调用该方法
*/
@Override
protected
void
handleTextMessage(WebSocketSession session, TextMessage message)
throws
Exception {
sendMessageToUsers(message);
//super.handleTextMessage(session, message);
}
/**
* 给某个用户发送消息
*
* @param userName
* @param message
*/
public
void
sendMessageToUser(String userName, TextMessage message) {
for
(WebSocketSession user : users) {
if
(user.getAttributes().get(Constants.WEBSOCKET_USERNAME).equals(userName)) {
try
{
if
(user.isOpen()) {
user.sendMessage(message);
}
}
catch
(IOException e) {
e.printStackTrace();
}
break
;
}
}
}
/**
* 给所有在线用户发送消息
*
* @param message
*/
public
void
sendMessageToUsers(TextMessage message) {
for
(WebSocketSession user : users) {
try
{
if
(user.isOpen()) {
user.sendMessage(message);
}
}
catch
(IOException e) {
e.printStackTrace();
}
}
}
@Override
public
void
handleTransportError(WebSocketSession session, Throwable exception)
throws
Exception {
if
(session.isOpen()) {
session.close();
}
logger.debug(
"websocket connection closed......"
);
users.remove(session);
}
@Override
public
void
afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus)
throws
Exception {
logger.debug(
"websocket connection closed......"
);
users.remove(session);
}
@Override
public
boolean
supportsPartialMessages() {
return
false
;
}
}
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spring-mvc.xml
正常的配置文件，同时需要增加对WebSocketConfig.java类的扫描，并且增加
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xmlns:websocket=
"http://www.springframework.org/schema/websocket"
http:
//www.springframework.org/schema/websocket
<a target=
"_blank"
href=
"http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd"
rel=
"external nofollow"
>http://www.springframework.org/schema/websocket/spring-websocket-
4.1
.xsd</a>
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客户端
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<script type=
"text/javascript"
<script>
var websocket;
if
(
'WebSocket'
in window) {
}
else
if
(
'MozWebSocket'
in window) {
}
else
{
}
websocket.onopen = function(evnt) {};
websocket.onmessage = function(evnt) {
$(
"#test"
).html(
"(<font color='red'>"
+ evnt.data +
"</font>)"
)
};
websocket.onerror = function(evnt) {};
websocket.onclose = function(evnt) {}
$(
'#btn'
).on(
'click'
, function() {
if
(websocket.readyState == websocket.OPEN) {
var msg = $(
'#id'
).val();
//调用后台handleTextMessage方法
websocket.send(msg);
}
else
{
alert(
"连接失败!"
);
}
});
</script>
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注意导入socketjs时要使用地址全称，并且连接使用的是http而不是websocket的ws