Java实现ping

最新推荐文章于 2025-06-02 00:15:00 发布

原创最新推荐文章于 2025-06-02 00:15:00 发布 · 190 阅读

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#Java #XML #Socket #Linux #.net

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一、纯Java 实现 ICMP 的 ping 命令

import java.io.*;
import java.net.*;
import java.nio.channels.*;
import java.util.*;
import java.util.regex.*;

public class Ping {
	static int DAYTIME_PORT = 13;
	static int port = DAYTIME_PORT;

	static class Target {
		InetSocketAddress address;
		SocketChannel channel;
		Exception failure;
		long connectStart;
		long connectFinish = 0;
		boolean shown = false;

		Target(String host) {
			try {
				address = new InetSocketAddress(InetAddress.getByName(host),
						port);
			} catch (IOException x) {
				failure = x;
			}
		}

		void show() {
			String result;
			if (connectFinish != 0)
				result = Long.toString(connectFinish - connectStart) + "ms";
			else if (failure != null)
				result = failure.toString();
			else
				result = "Timed out";
			System.out.println(address + " : " + result);
			shown = true;
		}
	}

	static class Printer extends Thread {
		LinkedList pending = new LinkedList();

		Printer() {
			setName("Printer");
			setDaemon(true);
		}

		void add(Target t) {
			synchronized (pending) {
				pending.add(t);
				pending.notify();
			}
		}

		public void run() {
			try {
				for (;;) {
					Target t = null;
					synchronized (pending) {
						while (pending.size() == 0)
							pending.wait();
						t = (Target) pending.removeFirst();
					}
					t.show();
				}
			} catch (InterruptedException x) {
				return;
			}
		}
	}

	static class Connector extends Thread {
		Selector sel;
		Printer printer;
		LinkedList pending = new LinkedList();

		Connector(Printer pr) throws IOException {
			printer = pr;
			sel = Selector.open();
			setName("Connector");
		}

		void add(Target t) {
			SocketChannel sc = null;
			try {
				sc = SocketChannel.open();
				sc.configureBlocking(false);
				boolean connected = sc.connect(t.address);
				t.channel = sc;
				t.connectStart = System.currentTimeMillis();
				if (connected) {
					t.connectFinish = t.connectStart;
					sc.close();
					printer.add(t);
				} else {
					synchronized (pending) {
						pending.add(t);
					}
					sel.wakeup();
				}
			} catch (IOException x) {
				if (sc != null) {
					try {
						sc.close();
					} catch (IOException xx) {
					}
				}
				t.failure = x;
				printer.add(t);
			}
		}

		void processPendingTargets() throws IOException {
			synchronized (pending) {
				while (pending.size() > 0) {
					Target t = (Target) pending.removeFirst();
					try {
						t.channel.register(sel, SelectionKey.OP_CONNECT, t);
					} catch (IOException x) {
						t.channel.close();
						t.failure = x;
						printer.add(t);
					}
				}
			}
		}

		void processSelectedKeys() throws IOException {
			for (Iterator i = sel.selectedKeys().iterator(); i.hasNext();) {
				SelectionKey sk = (SelectionKey) i.next();
				i.remove();
				Target t = (Target) sk.attachment();
				SocketChannel sc = (SocketChannel) sk.channel();
				try {
					if (sc.finishConnect()) {
						sk.cancel();
						t.connectFinish = System.currentTimeMillis();
						sc.close();
						printer.add(t);
					}
				} catch (IOException x) {
					sc.close();
					t.failure = x;
					printer.add(t);
				}
			}
		}

		volatile boolean shutdown = false;

		void shutdown() {
			shutdown = true;
			sel.wakeup();
		}

		public void run() {
			for (;;) {
				try {
					int n = sel.select();
					if (n > 0)
						processSelectedKeys();
					processPendingTargets();
					if (shutdown) {
						sel.close();
						return;
					}
				} catch (IOException x) {
					x.printStackTrace();
				}
			}
		}
	}

	public static void main(String[] args) throws InterruptedException,
			IOException {
		args = new String[] { "8888", "192.168.10.193" };
		if (args.length < 1) {
			System.err.println("Usage: java Ping [port] host...");
			return;
		}
		int firstArg = 0;
		if (Pattern.matches("[0-9]+", args[0])) {
			port = Integer.parseInt(args[0]);
			firstArg = 1;
		}
		Printer printer = new Printer();
		printer.start();
		Connector connector = new Connector(printer);
		connector.start();
		LinkedList targets = new LinkedList();
		for (int i = firstArg; i < args.length; i++) {
			Target t = new Target(args[i]);
			targets.add(t);
			connector.add(t);
		}
		Thread.sleep(2000);
		connector.shutdown();
		connector.join();
		for (Iterator i = targets.iterator(); i.hasNext();) {
			Target t = (Target) i.next();
			if (!t.shown)
				t.show();
		}
	}
}

二、JAVA 调用外部 EXE 实现 PING 功能

import java.io.*;
import java.lang.*;

public class Ping {
	public Ping() {
	}

	public static void main(String args[]) {
		if (args.length < 1) {
			System.out.println("syntax Error!");
		} else {
			String line = null;
			try {
				Process pro = Runtime.getRuntime().exec("ping " + args[0]);
				BufferedReader buf = new BufferedReader(new InputStreamReader(
						pro.getInputStream()));
				while ((line = buf.readLine()) != null)
					System.out.println(line);
			} catch (Exception ex) {
				System.out.println(ex.getMessage());
			}
		}
	}
}

三、ICMP Ping in Java(JDK 1.5 and above)

Programatically using ICMP Ping is a great way to establish that a server is up and running. Previously you couldn't do ICMP ping (what ping command does in Linux/Unix & Windows) in java without using JNI or exec calls. Here is a simple and reliable method to do ICMP pings in Java without using JNI or NIO.

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class Ping {
	public static void main(String args[]) {
		try {
			String host = "127.0.0.1";
			int timeOut = 1000; // I recommend 3 seconds at least
			boolean status = InetAddress.getByName(host).isReachable(timeOut);
			System.out.println(status);
		} catch (UnknownHostException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

status is true if the machine is reachable by ping; false otherwise. Best effort is made to try to reach the host, but firewalls and server configuration may block requests resulting in a unreachable status while some specific ports may be accessible. A typical implementation will use ICMP ECHO REQUESTs if the privilege can be obtained, otherwise it will try to establish a TCP connection on port 7 (Echo) of the destination host.

In Linux/Unix you may have to suid the java executable to get ICMP Ping working, ECHO REQUESTs will be fine even without suid. However on Windows you can get ICMP Ping without any issues whatsoever.

四、最简单的办法，直接调用CMD

import java.io.*;

public class Ping {
	public static void main(String args[]) {
		String line = null;
		try {
			Process pro = Runtime.getRuntime().exec("ping 127.0.0.1 ");
			BufferedReader buf = new BufferedReader(new InputStreamReader(pro
					.getInputStream()));
			while ((line = buf.readLine()) != null)
				System.out.println(line);
		} catch (Exception ex) {
			System.out.println(ex.getMessage());
		}
	}
}

五、模拟PING

利用InetAddress 的 isReachable 方法可以实现 ping 的功能，里面参数设定超时时间，返回结果表示是否连上

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;

public class Ping {
	public static void main(String args[]) {
		try {
			InetAddress address = InetAddress.getByName("127.0.0.1");
			System.out.println(address.isReachable(5000));
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

六、模拟TELNET

利用Socket 的 connect(SocketAddress endpoint, int timeout) 方法可以实现 telnet 的功能，如果 catch 到异常说明 telnet 失败

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.UnknownHostException;

public class Ping {
	public static void main(String args[]) {
		try {
			Socket server = new Socket();
			InetSocketAddress address = new InetSocketAddress("127.0.0.1",80);
			server.connect(address, 5000);
			server.close();
			System.out.println("telnet ok");
		} catch (UnknownHostException e) {
			System.out.println("telnet失败");
		} catch (IOException e) {
			System.out.println("telnet失败");
		}

	}
}

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