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src/main/java/com/yj/earth/common/util/NetUtils.java

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+package com.yj.earth.common.util;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.Socket;
+import java.net.UnknownHostException;
+import java.util.*;
+import java.util.concurrent.*;
+
+/**
+ * 网络工具类
+ */
+public class NetUtils {
+    private static final Logger logger = LoggerFactory.getLogger(NetUtils.class);
+
+    // Ping 超时时间（毫秒）
+    private static final int PING_TIMEOUT = 500;
+    // TCP Ping 端口
+    private static final int TCP_PING_PORT = 80;
+    // TCP Ping 超时时间（毫秒）
+    private static final int TCP_TIMEOUT = 1500;
+
+    private static final ExecutorService PING_EXECUTOR = Executors.newFixedThreadPool(
+            Math.min(Runtime.getRuntime().availableProcessors() * 2, 50),
+            new ThreadFactory() {
+                private int count = 0;
+                @Override
+                public Thread newThread(Runnable r) {
+                    Thread thread = new Thread(r);
+                    thread.setName("ping-executor-" + (count++));
+                    thread.setDaemon(true);
+                    return thread;
+                }
+            }
+    );
+
+    /**
+     * 使用 ICMP Echo Request (标准 Ping) 检测主机是否可达
+     * @param ipAddress IP地址或主机名
+     * @return true if reachable, false otherwise
+     */
+    public static boolean isReachableByIcmp(String ipAddress) {
+        if (ipAddress == null || ipAddress.trim().isEmpty()) {
+            return false;
+        }
+        try {
+            InetAddress address = InetAddress.getByName(ipAddress);
+            // isReachable 会尝试 ICMP Echo 和 TCP Echo (端口 7)
+            return address.isReachable(PING_TIMEOUT);
+        } catch (UnknownHostException e) {
+            logger.warn("未知的主机: {}", ipAddress);
+            return false;
+        } catch (IOException e) {
+            // 发生 IO 异常、视为不可达
+            return false;
+        }
+    }
+
+    /**
+     * 使用 TCP 连接检测主机端口是否开放（模拟 Ping）
+     * 当 ICMP 被防火墙禁止时、此方法更有效
+     * @param ipAddress IP地址
+     * @param port 端口号
+     * @return true if port is open, false otherwise
+     */
+    public static boolean isReachableByTcp(String ipAddress, int port) {
+        if (ipAddress == null || ipAddress.trim().isEmpty() || port < 1 || port > 65535) {
+            return false;
+        }
+        Socket socket = null;
+        try {
+            socket = new Socket();
+            socket.connect(new java.net.InetSocketAddress(ipAddress, port), TCP_TIMEOUT);
+            return true;
+        } catch (IOException e) {
+            // 连接失败、端口未开放或主机不可达
+            return false;
+        } finally {
+            if (socket != null) {
+                try {
+                    socket.close();
+                } catch (IOException e) {
+                    // ignore
+                }
+            }
+        }
+    }
+
+    /**
+     * 异步并发检测多个IP的可达性
+     * @param ips 需要检测的IP列表
+     * @return 一个 Map、key 是 IP、value 是 Boolean (是否在线)
+     * @throws ExecutionException 执行异常
+     * @throws InterruptedException 线程中断异常
+     */
+    public static Map<String, Boolean> checkReachabilityAsync(Collection<String> ips) throws ExecutionException, InterruptedException {
+        if (ips == null || ips.isEmpty()) {
+            return Collections.emptyMap();
+        }
+
+        List<Callable<Map.Entry<String, Boolean>>> tasks = new ArrayList<>();
+        for (String ip : ips) {
+            tasks.add(() -> {
+                boolean isOnline = isReachableByTcp(ip, TCP_PING_PORT) || isReachableByIcmp(ip);
+                return new AbstractMap.SimpleEntry<>(ip, isOnline);
+            });
+        }
+
+        List<Future<Map.Entry<String, Boolean>>> futures = PING_EXECUTOR.invokeAll(tasks);
+        Map<String, Boolean> results = new ConcurrentHashMap<>();
+        for (Future<Map.Entry<String, Boolean>> future : futures) {
+            Map.Entry<String, Boolean> entry = future.get();
+            results.put(entry.getKey(), entry.getValue());
+        }
+        return results;
+    }
+}