下面是我稍微改过的代码import java.io.*; import java.net.*; import java.nio.channels.*; import java.util.*; import java.util.regex.*;public class Ping { // The default daytime port static int DAYTIME_PORT = 13; // The port we"ll actually use static int port = DAYTIME_PORT;
// Representation of a ping target 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; } }
// Thread for printing targets as they"re heard from static class Printer extends Thread { LinkedList<Target> pending = new LinkedList<Target>(); //创建储存Target对象的列表
public void run() { try { for (;;) { Target t = null; synchronized (pending) { while (pending.size() == 0) pending.wait(); //当前线程处于等待状态，直到pending.notify() t = pending.removeFirst(); //移除并返回此列表的第一个元素 } t.show(); //显示目标信息 } } catch (InterruptedException x) { return; } } }
// Thread for connecting to all targets in parallel via a single selector static class Connector extends Thread { Selector sel; Printer printer; // List of pending targets. We use this list because if we try to // register a channel with the selector while the connector thread is // blocked in the selector then we will block.
LinkedList<Target> pending = new LinkedList<Target>();
// Initiate a connection sequence to the given target and add the // target to the pending-target list
void add(Target t) { SocketChannel sc = null; try { // Open the channel, set it to non-blocking, initiate connect sc = SocketChannel.open(); sc.configureBlocking(false); boolean connected = sc.connect(t.address); // Record the time we started t.channel = sc; t.connectStart = System.currentTimeMillis(); if (connected) { t.connectFinish = t.connectStart; sc.close(); printer.add(t); } else { // Add the new channel to the pending list synchronized (pending) { pending.add(t); } // Nudge the selector so that it will process the pending list sel.wakeup(); //使尚未返回的第一个选择操作立即返回 } } catch (IOException x) { if (sc != null) { try { sc.close(); } catch (IOException xx) { } } t.failure = x; printer.add(t); } }
// Process any targets in the pending list void processPendingTargets() throws IOException { synchronized (pending) { while (pending.size() > 0) { Target t = (Target) pending.removeFirst(); try { // Register the channel with the selector, indicating // interest in connection completion and attaching the // target object so that we can get the target back // after the key is added to the selector"s // selected-key set t.channel.register(sel, SelectionKey.OP_CONNECT, t); } catch (IOException x) { // Something went wrong, so close the channel and // record the failure t.channel.close(); t.failure = x; printer.add(t); } } } } // Process keys that have become selected void processSelectedKeys() throws IOException { for (Iterator<SelectionKey> i = sel.selectedKeys().iterator(); i.hasNext();) { // Retrieve the next key and remove it from the set SelectionKey sk = i.next(); i.remove(); // Retrieve the target and the channel Target t = (Target) sk.attachment(); SocketChannel sc = (SocketChannel) sk.channel(); // Attempt to complete the connection sequence 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; // Invoked by the main thread when it"s time to shut down void shutdown() { shutdown = true; sel.wakeup(); } // Connector loop 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[] { "80", "192.168.1.100" }; //测试用 if (args.length < 1) { System.err.println("Usage: java Ping [port] host..."); return; } int firstArg = 0; // If the first argument is a string of digits then we take that // to be the port number to use if (Pattern.matches("[0-9]+", args[0])) { port = Integer.parseInt(args[0]); firstArg = 1; } // Create the threads and start them up Printer printer = new Printer(); printer.start(); Connector connector = new Connector(printer); connector.start(); // Create the targets and add them to the connector LinkedList<Target> targets = new LinkedList<Target>(); for (int i = firstArg; i < args.length; i++) { Target t = new Target(args[i]); targets.add(t); connector.add(t); } // Wait for everything to finish Thread.sleep(2000); connector.shutdown(); connector.join(); // Print status of targets that have not yet been shown for (Iterator<Target> i = targets.iterator(); i.hasNext();) { Target t = i.next(); if (!t.shown) t.show(); } } }
/* * @(#)Ping.java 1.2 01/12/13 * Connect to each of a list of hosts and measure the time required to complete * the connection. This example uses a selector and two additional threads in * order to demonstrate non-blocking connects and the multithreaded use of a * selector. * * Copyright 2001-2002 Sun Microsystems, Inc. All Rights Reserved. * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * -Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * -Redistribution in binary form must reproduct the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * Neither the name of Sun Microsystems, Inc. or the names of * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * This software is provided "AS IS," without a warranty of any * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY * DAMAGES OR LIABILITIES SUFFERED BY LICENSEE AS A RESULT OF OR * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR * ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE * FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, * SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF * THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. * * You acknowledge that Software is not designed, licensed or * intended for use in the design, construction, operation or * maintenance of any nuclear facility. */import java.io.*; import java.net.*; import java.nio.*; import java.nio.channels.*; import java.nio.charset.*; import java.util.*; import java.util.regex.*; public class Ping { // The default daytime port static int DAYTIME_PORT = 13; // The port we'll actually use static int port = DAYTIME_PORT; // Representation of a ping target // 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; } } // Thread for printing targets as they're heard from // 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; } } } // Thread for connecting to all targets in parallel via a single selector // static class Connector extends Thread { Selector sel; Printer printer; // List of pending targets. We use this list because if we try to // register a channel with the selector while the connector thread is // blocked in the selector then we will block. // LinkedList pending = new LinkedList(); Connector(Printer pr) throws IOException { printer = pr; sel = Selector.open(); setName("Connector"); } // Initiate a connection sequence to the given target and add the // target to the pending-target list // void add(Target t) { SocketChannel sc = null; try { // Open the channel, set it to non-blocking, initiate connect sc = SocketChannel.open(); sc.configureBlocking(false); boolean connected = sc.connect(t.address); // Record the time we started t.channel = sc; t.connectStart = System.currentTimeMillis(); if (connected) { t.connectFinish = t.connectStart; sc.close(); printer.add(t); } else { // Add the new channel to the pending list synchronized (pending) { pending.add(t); } // Nudge the selector so that it will process the pending list sel.wakeup(); } } catch (IOException x) { if (sc != null) { try { sc.close(); } catch (IOException xx) { } } t.failure = x; printer.add(t); } } // Process any targets in the pending list // void processPendingTargets() throws IOException { synchronized (pending) { while (pending.size() > 0) { Target t = (Target)pending.removeFirst(); try { // Register the channel with the selector, indicating // interest in connection completion and attaching the // target object so that we can get the target back // after the key is added to the selector's // selected-key set t.channel.register(sel, SelectionKey.OP_CONNECT, t); } catch (IOException x) { // Something went wrong, so close the channel and // record the failure t.channel.close(); t.failure = x; printer.add(t); } } } } // Process keys that have become selected // void processSelectedKeys() throws IOException { for (Iterator i = sel.selectedKeys().iterator(); i.hasNext();) { // Retrieve the next key and remove it from the set SelectionKey sk = (SelectionKey)i.next(); i.remove(); // Retrieve the target and the channel Target t = (Target)sk.attachment(); SocketChannel sc = (SocketChannel)sk.channel(); // Attempt to complete the connection sequence 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; // Invoked by the main thread when it's time to shut down // void shutdown() { shutdown = true; sel.wakeup(); } // Connector loop // 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 { if (args.length < 1) { System.err.println("Usage: java Ping [port] host..."); return; } int firstArg = 0; // If the first argument is a string of digits then we take that // to be the port number to use if (Pattern.matches("[0-9]+", args[0])) { port = Integer.parseInt(args[0]); firstArg = 1; } // Create the threads and start them up Printer printer = new Printer(); printer.start(); Connector connector = new Connector(printer); connector.start(); // Create the targets and add them to the connector LinkedList targets = new LinkedList(); for (int i = firstArg; i < args.length; i++) { Target t = new Target(args[i]); targets.add(t); connector.add(t); } // Wait for everything to finish Thread.sleep(2000); connector.shutdown(); connector.join(); // Print status of targets that have not yet been shown for (Iterator i = targets.iterator(); i.hasNext();) { Target t = (Target)i.next(); if (!t.shown) t.show(); } }}
public class CmdTest { private static final long serialVersionUID = -2650474785662737262L; public static void main(String[] args) throws Exception {
Runtime runtime = Runtime.getRuntime();
Process p = runtime.exec("cmd /c ping 127.0.0.1");
DealStream errStream = new DealStream(p.getErrorStream(),"Err");
DealStream outStream = new DealStream(p.getInputStream(),"Out");
new Thread(errStream).start();
new Thread(outStream).start();
int exitValue = p.waitFor();
System.out.println("exitValue -- > " + exitValue);
}}
class DealStream implements Runnable{
private InputStream is;
private String type; public DealStream(InputStream is,String type){
this.is = is;
this.type = type;
} public void run(){
try{
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String temp = null;
while((temp = br.readLine()) != null){
System.out.println(type + "-->" + temp + "\n");
}
}catch(Exception e){
e.printStackTrace();
}finally{
try{
is.close();
}catch(Exception ex){
ex.printStackTrace();
}
}
}
}
就是所谓的Socket编程。
http://java.sun.com/javase/6/docs/technotes/guides/io/example/index.html
只是用了多线程和JNI罢了。运行后发现有很大的问题（ping不通），也不知道是怎么回事。
import java.net.*;
import java.nio.channels.*;
import java.util.*;
import java.util.regex.*;public class Ping {
// The default daytime port
static int DAYTIME_PORT = 13;
// The port we"ll actually use
static int port = DAYTIME_PORT;
// Representation of a ping target
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;
}
}
// Thread for printing targets as they"re heard from
static class Printer extends Thread {
LinkedList<Target> pending = new LinkedList<Target>(); //创建储存Target对象的列表
Printer() {
setName("Printer"); //设置线程的新名称
setDaemon(true); //标记该进程为守护进程,当正在运行的线程都是守护线程时，Java虚拟机退出。
}
void add(Target t) {
synchronized (pending) {
pending.add(t); //将Target对象添加进列表pending
pending.notify(); //唤醒在此对象监视器上等待的单个线程
}
}
public void run() {
try {
for (;;) {
Target t = null;
synchronized (pending) {
while (pending.size() == 0)
pending.wait(); //当前线程处于等待状态，直到pending.notify()
t = pending.removeFirst(); //移除并返回此列表的第一个元素
}
t.show(); //显示目标信息
}
}
catch (InterruptedException x) {
return;
}
}
}
// Thread for connecting to all targets in parallel via a single selector
static class Connector extends Thread {
Selector sel;
Printer printer;
// List of pending targets. We use this list because if we try to
// register a channel with the selector while the connector thread is
// blocked in the selector then we will block.
LinkedList<Target> pending = new LinkedList<Target>();
Connector(Printer pr) throws IOException {
printer = pr;
sel = Selector.open(); //打开一个选择器
setName("Connector"); //设置线程的新名称
}
// Initiate a connection sequence to the given target and add the
// target to the pending-target list
void add(Target t) {
SocketChannel sc = null;
try {
// Open the channel, set it to non-blocking, initiate connect
sc = SocketChannel.open();
sc.configureBlocking(false);
boolean connected = sc.connect(t.address);
// Record the time we started
t.channel = sc;
t.connectStart = System.currentTimeMillis();
if (connected) {
t.connectFinish = t.connectStart;
sc.close();
printer.add(t);
} else {
// Add the new channel to the pending list
synchronized (pending) {
pending.add(t);
}
// Nudge the selector so that it will process the pending list
sel.wakeup(); //使尚未返回的第一个选择操作立即返回
}
}
catch (IOException x) {
if (sc != null) {
try {
sc.close();
} catch (IOException xx) {
}
} t.failure = x;
printer.add(t);
}
}
// Process any targets in the pending list
void processPendingTargets() throws IOException {
synchronized (pending) {
while (pending.size() > 0) {
Target t = (Target) pending.removeFirst();
try {
// Register the channel with the selector, indicating
// interest in connection completion and attaching the
// target object so that we can get the target back
// after the key is added to the selector"s
// selected-key set
t.channel.register(sel, SelectionKey.OP_CONNECT, t);
} catch (IOException x) {
// Something went wrong, so close the channel and
// record the failure
t.channel.close();
t.failure = x;
printer.add(t);
}
}
}
}
// Process keys that have become selected
void processSelectedKeys() throws IOException {
for (Iterator<SelectionKey> i = sel.selectedKeys().iterator(); i.hasNext();) {
// Retrieve the next key and remove it from the set
SelectionKey sk = i.next();
i.remove();
// Retrieve the target and the channel
Target t = (Target) sk.attachment();
SocketChannel sc = (SocketChannel) sk.channel();
// Attempt to complete the connection sequence
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;
// Invoked by the main thread when it"s time to shut down
void shutdown() {
shutdown = true;
sel.wakeup();
}
// Connector loop
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[] { "80", "192.168.1.100" }; //测试用
if (args.length < 1) {
System.err.println("Usage: java Ping [port] host...");
return;
}
int firstArg = 0;
// If the first argument is a string of digits then we take that
// to be the port number to use
if (Pattern.matches("[0-9]+", args[0])) {
port = Integer.parseInt(args[0]);
firstArg = 1;
}
// Create the threads and start them up
Printer printer = new Printer();
printer.start();
Connector connector = new Connector(printer);
connector.start();
// Create the targets and add them to the connector
LinkedList<Target> targets = new LinkedList<Target>();
for (int i = firstArg; i < args.length; i++) {
Target t = new Target(args[i]);
targets.add(t);
connector.add(t);
}
// Wait for everything to finish
Thread.sleep(2000);
connector.shutdown();
connector.join();
// Print status of targets that have not yet been shown
for (Iterator<Target> i = targets.iterator(); i.hasNext();) {
Target t = i.next();
if (!t.shown)
t.show();
}
}
}
这里找到一个比较完整的总结。看来我得放弃用Java实现了
我使用socket 实现国http,ftp 不是很难.
主要是要知道协议.
/*
* @(#)Ping.java 1.2 01/12/13
* Connect to each of a list of hosts and measure the time required to complete
* the connection. This example uses a selector and two additional threads in
* order to demonstrate non-blocking connects and the multithreaded use of a
* selector.
*
* Copyright 2001-2002 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* -Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* -Redistribution in binary form must reproduct the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any
* kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
* WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY
* EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY
* DAMAGES OR LIABILITIES SUFFERED BY LICENSEE AS A RESULT OF OR
* RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR
* ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE
* FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT,
* SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF
* THE USE OF OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that Software is not designed, licensed or
* intended for use in the design, construction, operation or
* maintenance of any nuclear facility.
*/import java.io.*;
import java.net.*;
import java.nio.*;
import java.nio.channels.*;
import java.nio.charset.*;
import java.util.*;
import java.util.regex.*;
public class Ping { // The default daytime port
static int DAYTIME_PORT = 13; // The port we'll actually use
static int port = DAYTIME_PORT;
// Representation of a ping target
//
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;
} }
// Thread for printing targets as they're heard from
//
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;
}
} }
// Thread for connecting to all targets in parallel via a single selector
//
static class Connector
extends Thread
{
Selector sel;
Printer printer; // List of pending targets. We use this list because if we try to
// register a channel with the selector while the connector thread is
// blocked in the selector then we will block.
//
LinkedList pending = new LinkedList(); Connector(Printer pr) throws IOException {
printer = pr;
sel = Selector.open();
setName("Connector");
} // Initiate a connection sequence to the given target and add the
// target to the pending-target list
//
void add(Target t) {
SocketChannel sc = null;
try { // Open the channel, set it to non-blocking, initiate connect
sc = SocketChannel.open();
sc.configureBlocking(false); boolean connected = sc.connect(t.address); // Record the time we started
t.channel = sc;
t.connectStart = System.currentTimeMillis(); if (connected) {
t.connectFinish = t.connectStart;
sc.close();
printer.add(t);
} else {
// Add the new channel to the pending list
synchronized (pending) {
pending.add(t);
} // Nudge the selector so that it will process the pending list
sel.wakeup();
}
} catch (IOException x) {
if (sc != null) {
try {
sc.close();
} catch (IOException xx) { }
}
t.failure = x;
printer.add(t);
}
} // Process any targets in the pending list
//
void processPendingTargets() throws IOException {
synchronized (pending) {
while (pending.size() > 0) {
Target t = (Target)pending.removeFirst();
try { // Register the channel with the selector, indicating
// interest in connection completion and attaching the
// target object so that we can get the target back
// after the key is added to the selector's
// selected-key set
t.channel.register(sel, SelectionKey.OP_CONNECT, t); } catch (IOException x) { // Something went wrong, so close the channel and
// record the failure
t.channel.close();
t.failure = x;
printer.add(t); } }
}
} // Process keys that have become selected
//
void processSelectedKeys() throws IOException {
for (Iterator i = sel.selectedKeys().iterator(); i.hasNext();) { // Retrieve the next key and remove it from the set
SelectionKey sk = (SelectionKey)i.next();
i.remove(); // Retrieve the target and the channel
Target t = (Target)sk.attachment();
SocketChannel sc = (SocketChannel)sk.channel(); // Attempt to complete the connection sequence
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; // Invoked by the main thread when it's time to shut down
//
void shutdown() {
shutdown = true;
sel.wakeup();
} // Connector loop
//
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
{
if (args.length < 1) {
System.err.println("Usage: java Ping [port] host...");
return;
}
int firstArg = 0; // If the first argument is a string of digits then we take that
// to be the port number to use
if (Pattern.matches("[0-9]+", args[0])) {
port = Integer.parseInt(args[0]);
firstArg = 1;
} // Create the threads and start them up
Printer printer = new Printer();
printer.start();
Connector connector = new Connector(printer);
connector.start(); // Create the targets and add them to the connector
LinkedList targets = new LinkedList();
for (int i = firstArg; i < args.length; i++) {
Target t = new Target(args[i]);
targets.add(t);
connector.add(t);
} // Wait for everything to finish
Thread.sleep(2000);
connector.shutdown();
connector.join(); // Print status of targets that have not yet been shown
for (Iterator i = targets.iterator(); i.hasNext();) {
Target t = (Target)i.next();
if (!t.shown)
t.show();
} }}