设计并实现一个Ping程序，以掌握UDP套接字的使用以及ICMP协议中ECHO报文的发送和接受方法。

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());
}
}

}
}

熟练掌握ping的用法 ping是对TCP/IP网络上的任意一台计算机发送一个请求ICMP...秒，并打印发送和接收把报文的数量。比较每个接收报文和发送报文，以校验其...

二胖子，过来，我教你