Flutter websocket 实现消息推送 - 好文

没什么可说的，直接上代码吧

* Flutter 中的消息管理工具： class MessageUtils { static WebSocket _webSocket; static
num _id = 0; static void connect() { Future<WebSocket> futureWebSocket =
WebSocket.connect(Api.WS_URL +"/leyan");// Api.WS_URL 为服务器端的 websocket 服务
futureWebSocket.then((WebSocket ws) { _webSocket = ws; _webSocket.readyState;//
监听事件 void onData(dynamic content) { _id++; _sendMessage("收到");
_createNotification("新消息", content + _id.toString()); }
_webSocket.listen(onData, onError: (a) =>print("error"), onDone: () => print(
"done")); }); } static void closeSocket() { _webSocket.close(); } // 向服务器发送消息
static void _sendMessage(String message) { _webSocket.add(message); } //
手机状态栏弹出推送的消息 static void _createNotification(String title, String content) async
{await LocalNotifications.createNotification( id: _id, title: title, content:
content, onNotificationClick: NotificationAction( actionText:"some action",
callback: _onNotificationClick, payload:"接收成功！"), ); } static
_onNotificationClick(String payload) {
LocalNotifications.removeNotification(_id); _sendMessage("消息已被阅读"); } } 复制代码
* websocket 服务： @ServerEndpoint(value = "/api/ws/{userid}")// 对应 Api.WS_URL
@Component public class SocketServer { private Session session; private static
Map<String, Session> sessionPool =new HashMap<>(); private static Map<String,
String> sessionIds =new HashMap<>(); private static Map<String,
TreeSet<String>> remainingMessagePool =new HashMap<>(128); /** * 用户连接时触发 * *
@param session * @param userid */ @OnOpen public void open(Session session,
@PathParam(value ="userid") String userid) { this.session = session;
sessionPool.put(userid, session); sessionIds.put(session.getId(), userid);//
离线消息发送 if (remainingMessagePool.get(userid) != null) { TreeSet<String>
remainingMessages = remainingMessagePool.get(userid);
remainingMessages.forEach(it -> sendMessage(it, userid));
remainingMessagePool.remove(userid); } }/** * 收到信息时触发 * * @param message */
@OnMessage public void onMessage(String message) { System.out.println("发送人:" +
sessionIds.get(session.getId()) +"内容:" + message); } /** * 连接关闭触发 */ @OnClose
public void onClose() { sessionPool.remove(sessionIds.get(session.getId()));
sessionIds.remove(session.getId()); }/** * 发生错误时触发 * * @param session * @param
error */ @OnError public void onError(Session session, Throwable error) {
error.printStackTrace(); }/** * 信息发送的方法 * * @param message * @param userId */
public static void sendMessage(String message, String userId) { Session s =
sessionPool.get(userId);if (s != null) { try {
s.getBasicRemote().sendText(message); }catch (IOException e) {
e.printStackTrace(); } }else { // 离线消息存储 if (remainingMessagePool.get(userId) !=
null) { TreeSet<String> remainingMessages = remainingMessagePool.get(userId);
remainingMessages.add(message); }else { TreeSet<String> remainingMessages = new
TreeSet<>(); remainingMessages.add(message); remainingMessagePool.put(userId,
remainingMessages); } } }/** * 获取当前连接数 * * @return */ public static int
getOnlineNum() { return sessionPool.size(); } /** * 获取在线用户名以逗号隔开 * * @return */
public static String getOnlineUsers() { StringBuffer users = new StringBuffer();
for (String key : sessionIds.keySet()) { users.append(sessionIds.get(key) + ","
); }return users.toString(); } /** * 信息群发 * * @param msg */ public static void
sendAll(String msg) { for (String key : sessionIds.keySet()) { sendMessage(msg,
sessionIds.get(key)); } }/** * 多个人发送给指定的几个用户 * * @param msg * @param persons
用户s */ public static void SendMany(String msg, String[] persons) { for (String
userid : persons) { sendMessage(msg, userid); } } }复制代码

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