Java 實現Ping功能

一、純Java實現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調用外部EXE實現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.

String host = "172.16.0.2"int timeOut = 3000; // I recommend 3 seconds at leastboolean status = InetAddress.getByName(host).isReachable(timeOut)

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、最簡單的辦法，直接調用CMD

 try        {         Runtime.getRuntime().exec("cmd /c start ping 127.0.0.1");        }        catch (Exception ex)        {            System.out.println(ex.getMessage());        }

ping的過程可以顯示在本地的辦法

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、類比PING

利用InetAddress的isReachable方法可以實現ping的功能，裡面參數設定逾時時間，返回結果表示是否連上

try {            InetAddress address = InetAddress.getByName("192.168.0.113");            System.out.println(address.isReachable(5000));        } catch (UnknownHostException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        }

六、類比TELNET    利用Socket的connect(SocketAddress endpoint, int timeout)方法可以實現telnet的功能，如果catch到異常說明telnet失敗

 try  {           Socket server = new Socket();           InetSocketAddress address = new InetSocketAddress("192.168.0.113",                    8080);           server.connect(address, 5000);           server.close();        } catch (UnknownHostException e){            System.out.println("telnet失敗");        } catch (IOException e){            System.out.println("telnet失敗");        }

轉自：http://blog.sina.com.cn/s/blog_4b00fd1b0100by7z.html