實現長連接
由於websocket連接成功過段時間自動關閉,無法繼續獲取消息
於是我就想到一個辦法,就是自動關閉時再重新創建一次(因爲自動關閉也不是很快就關閉的,所以我就這麼寫),雖然實現方式不是很好,但是也暫時的實現了長連接方式
前端JS
var websocket = null;
var host = document.location.host;
var username = "1001"; // 獲得當前登錄人員的userName --這裏使用當前項目ID做判斷
var judgeTemp = 0;
// alert(username)
createWebSorket();
function createWebSorket(){
//判斷當前瀏覽器是否支持WebSocket
if('WebSocket' in window) {
websocket = new WebSocket('ws://' + host + '/Project/webSocket/' + username);
initEventHandle();
} else {
alert('當前瀏覽器 Not support websocket,消息推送將無法使用')
}
}
function initEventHandle(){
//連接發生錯誤的回調方法
websocket.onerror = function() {
judgeTemp = 1;
//這裏就是你要顯示的信息的函數(自定義)
setMessageInnerHTML("WebSocket消息推送連接發生錯誤",1);
};
//連接成功建立的回調方法
websocket.onopen = function() {
//這裏就是你要顯示的信息的函數(自定義)
setMessageInnerHTML("WebSocket消息推送連接成功",1);
console.log("成功連接---"+judgeTemp)
}
//接收到消息的回調方法
websocket.onmessage = function(event) {
//這裏就是你要顯示的信息的函數(自定義)
setMessageInnerHTML(event.data);
}
//連接關閉的回調方法
websocket.onclose = function() {
console.log("關閉連接---"+judgeTemp)
if(judgeTemp == 1){
//這裏就是你要顯示的信息的函數(自定義)
setMessageInnerHTML("WebSocket消息推送連接關閉",1);
}else{
createWebSorket();
}
}
//監聽窗口關閉事件,當窗口關閉時,主動去關閉websocket連接,防止連接還沒斷開就關閉窗口,server端會拋異常。
window.onbeforeunload = function() {
judgeTemp = 1;
closeWebSocket();
}
}
//關閉WebSocket連接
function closeWebSocket() {
websocket.close();
}
後端實現
我這裏是用SSH的框架(其實也沒啥區別的)
package com.action;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
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 static List<Map<String, WebSocket>> clients = null;
private Session session;
private String username;
@OnOpen
public void onOpen(@PathParam("username") String username, Session session) throws IOException {
this.username = username;
this.session = session;
//爲了實現多個頁面登錄同一個賬號時,同時推送全部頁面
if(clients == null) {
synchronized (WebSocket.class) {
if(clients == null) {
clients = new ArrayList<Map<String, WebSocket>>();
}
}
}
addOnlineCount();
Map<String, WebSocket> clien = new ConcurrentHashMap<String, WebSocket>();
clien.put(username, this);
clients.add(clien);
//clients.put(username, this);
//System.out.println("已連接");
}
@OnClose
public void onClose() throws IOException {
for(int i=0; i< clients.size(); i++) {
Map<String, WebSocket> clien = clients.get(i);
for (WebSocket item : clien.values()) {
if(item.session.equals(session))
clients.remove(i);
}
}
//clients.remove(username);
subOnlineCount();
}
@OnMessage
public void onMessage(String message) throws IOException {
JSONObject jsonTo = JSONObject.fromObject(message);
String mes = (String) jsonTo.get("message");
if (!jsonTo.get("To").equals("All")){
sendMessageTo(mes, jsonTo.get("To").toString());
}else{
sendMessageAll(mes);
}
}
@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);
} */
for(int i=0; i< clients.size(); i++) {
Map<String, WebSocket> clien = clients.get(i);
for (WebSocket item : clien.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);
} */
for(int i=0; i< clients.size(); i++) {
Map<String, WebSocket> clien = clients.get(i);
for (WebSocket item : clien.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;
} */
public static synchronized List<Map<String, WebSocket>> getClients() {
return clients;
}
}
備註
如果遇到無法找到問題
通道:https://blog.csdn.net/weixin_43992507/article/details/103256233
或
nginx下無法連接websocket
通道:https://blog.csdn.net/weixin_43992507/article/details/103337106