✨ 考虑使用 udp 多播做集群。

mica-mqtt-core/src/main/java/net/dreamlu/iot/mqtt/core/server/cluster/package-info.java

+package net.dreamlu.iot.mqtt.core.server.cluster;

mica-mqtt-core/src/test/java/net/dreamlu/iot/mqtt/core/udp/Node1.java

+/*
+ * Copyright (c) 2019-2029, Dreamlu 卢春梦 (596392912@qq.com & dreamlu.net).
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.dreamlu.iot.mqtt.core.udp;
+
+import java.net.DatagramPacket;
+import java.net.InetAddress;
+import java.net.MulticastSocket;
+
+public class Node1 {
+    public static void main(String[] args) throws Exception {
+        int port = 12345;
+        // 多播 ip 段 224.0.0.0 to 239.255.255.255
+        MulticastSocket multicastSocket = new MulticastSocket(port);
+        InetAddress group = InetAddress.getByName("224.0.0.1");
+        multicastSocket.joinGroup(group);
+        System.out.println("Multicast Receiver running at:" + multicastSocket.getLocalSocketAddress());
+
+        while (true) {
+            DatagramPacket dp = new DatagramPacket(new byte[1024], 1024);
+            multicastSocket.receive(dp);
+            String s = new String(dp.getData(), 0, dp.getLength());
+            System.out.println("receive: " + s);
+        }
+
+//        mcSocket.leaveGroup(group);
+//        mcSocket.close();
+    }
+}

mica-mqtt-core/src/test/java/net/dreamlu/iot/mqtt/core/udp/Node2.java

+/*
+ * Copyright (c) 2019-2029, Dreamlu 卢春梦 (596392912@qq.com & dreamlu.net).
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.dreamlu.iot.mqtt.core.udp;
+
+import java.io.IOException;
+import java.net.DatagramPacket;
+import java.net.InetAddress;
+import java.net.MulticastSocket;
+import java.util.Timer;
+import java.util.TimerTask;
+
+public class Node2 {
+    public static void main(String[] args) throws Exception {
+        int port = 12345;
+        // 多播 ip 段 224.0.0.0 to 239.255.255.255
+        MulticastSocket multicastSocket = new MulticastSocket(port);
+        InetAddress group = InetAddress.getByName("224.0.0.1");
+        multicastSocket.joinGroup(group);
+
+        System.out.println("Multicast Receiver running at:" + multicastSocket.getLocalSocketAddress());
+
+        String message = "Hello from node2";
+        byte[] buffer = message.getBytes();
+
+        TimerTask timerTask = new TimerTask() {
+            @Override
+            public void run() {
+                DatagramPacket packet = new DatagramPacket(buffer, buffer.length, group, port);
+                try {
+                    multicastSocket.send(packet);
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+            }
+        };
+
+        Timer timer = new Timer();
+        timer.schedule(timerTask, 1000, 1000);
+//        mcSocket.leaveGroup(group);
+//        mcSocket.close();
+    }
+}