package org.meal.controller;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
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;
@ServerEndpoint("/websockets")
public class WebscoketsController extends HttpServlet{
//concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。若要实现服务端与单一客户端通信的话，可以使用Map来存放，其中Key可以为用户标识
private static CopyOnWriteArraySet<WebscoketsController> webSocketSet = new CopyOnWriteArraySet<WebscoketsController>();
//这个session不是Httpsession，相当于用户的唯一标识，用它进行与指定用户通讯
private javax.websocket.Session session=null;
public void doGet(HttpServletRequest request, HttpServletResponse response,long deskId,long shopid) throws ServletException,IOException {
//发送更新信号
sendMessage(deskId,shopid);
//response.sendRedirect("http://localhost:8080/order_meal/checkstand/index.jsp");
}
public void doPost(HttpServletRequest request,HttpServletResponse reponse) throws ServletException, IOException {
doGet(request,reponse);
}
/**
* @OnOpen allows us to intercept the creation of a new session.
* The session class allows us to send data to the user.
* In the method onOpen, we'll let the user know that the handshake was
* successful.
* 建立websocket连接时调用
*/
@OnOpen
public void onOpen(Session session){
System.out.println("Session " + session.getId() + " has opened a connection");
try {
this.session=session;
webSocketSet.add(this); //加入set中
session.getBasicRemote().sendText("Connection Established");
} catch (IOException ex) {
ex.printStackTrace();
}
}
/**
* When a user sends a message to the server, this method will intercept the message
* and allow us to react to it. For now the message is read as a String.
* 接收到客户端消息时使用，这个例子里没用
*/
@OnMessage
public void onMessage(String message, Session session){
System.out.println("Message from " + session.getId() + ": " + message);
}
/**
* The user closes the connection.
*
* Note: you can't send messages to the client from this method
* 关闭连接时调用
*/
@OnClose
public void onClose(Session session){
webSocketSet.remove(this); //从set中删除
System.out.println("Session " +session.getId()+" has closed!");
}
/**
* 注意: OnError() 只能出现一次. 其中的参数都是可选的。
* @param session
* @param t
*/
@OnError
public void onError(Session session, Throwable t) {
t.printStackTrace();
}
/**
* 这个方法与上面几个方法不一样。没有用注解，是根据自己需要添加的方法。
* @throws IOException
* 发送自定义信号，“1”表示告诉前台，数据库发生改变了，需要刷新
*/
public void sendMessage(long deskId,long shopid) throws IOException{
String id=String.valueOf(deskId);
String shop=String.valueOf(shopid);
String ids=id+","+shop;
//群发消息
for(WebscoketsController item: webSocketSet){
try {
item.session.getBasicRemote().sendText(ids);
} catch (IOException e) {
e.printStackTrace();
continue;
}
}
}
}
//在传送消息时，需要调用webscoket的doget函数
WebscoketsController controller2 = new WebscoketsController();
try {
controller2.doGet(request, response, list.get(list.size()-1).getDeskId(), shopId);
} catch (ServletException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
jsp页面
var websocket = null;
//判断当前浏览器是否支持WebSocket
if ('WebSocket' in window) {
//建立连接，这里的/websocket ，是ManagerServlet中开头注解中的那个值
websocket = new WebSocket("ws://115.158.20.211:8080/order_meal/websockets");
}
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);
if(event.data=="1"){
location.reload();
}
}
//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();
}
//将消息显示在网页上
function setMessageInnerHTML(innerHTML) {
var ids=innerHTML.split(",");
var deskId;
var shopId;
var shop="${admin.shopId}";
console.log(shop)
for(var i=0;i<ids.length;i++){
deskId=ids[i];
shopId=ids[i+1];
break;
}
if(shop==shopId){
$('#imgdiv').append(' <img alt="" src="images/message.png" class="imgclass" id="message">');
var msg = "测试语音播放";
var re = /^[0-9]+.?[0-9]*$/;
if (re.test(innerHTML)){
var str=deskId+'号餐桌已结账';
voiceAnnouncements(str);
}
console.log(innerHTML);
}
}
//关闭WebSocket连接
function closeWebSocket() {
websocket.close();
}
function voiceAnnouncements(str){
//百度
var url = "http://tts.baidu.com/text2audio?lan=zh&ie=UTF-8&text=" + encodeURI(str); // baidu
var n = new Audio(url);
n.src = url;
n.play();
}
</script>
