Java开发网 - 求助(在局域网内如何获得所有网络计算机的名字和ip)

Topic: 求助(在局域网内如何获得所有网络计算机的名字和ip)

1.求助(在局域网内如何获得所有网络计算机的名字和ip)	Copy to clipboard
Posted by: cqlgc Posted on: 2003-11-22 14:23 请问在局域网内部，如何获得所有的网络计算机。计算机的名字和ip地址！

2.Re:求助 [Re: cqlgc]	Copy to clipboard
Posted by: lcwling Posted on: 2003-11-22 21:46 如果要用j纯ava语言实现,我想恐怕很难吧 !如果在windows下,自己编写jni可能就容易一些,关注....

3.Re:求助(在局域网内如何获得所有网络计算机的名字和ip) [Re: cqlgc]

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Posted by: alin_ass
Posted on: 2003-11-23 20:16

贴以前写的，有个小问题，我不懂jdk的，请问为什么这个类我用起来有时搜索结果，并且返回没有结果的时间太长了，怎么设置超时就算无效ip，请高手支援
/* ------------------------------------------------------------------
* Copyright: Free software.
* Author: Alin&ASS(AlinSoftStudio)
* Email: alin_ASS@hotmail.com
* Time: 12:33:00 2003-11-9
* Project：alinjava
* Readme: If you make any modification or have some advice
* about this application, I am very glad to know about it.
*
* Description: Gain a list of machinenames to specified
* address in LAN(local area network). The result may not be
* complete. I guess simplicity it it becuase of the thread
* which use the java.net.InetAddress.getByAddress(byte[])
* will blocked in the Scoket(the more threads the worse)so
* as to lose some machinenames.
* ------------------------------------------------------------------
*/
import java.net.*;
/**
* Gain a list of machinenames between
* address 192.168.0.x~192.168.0.y.
* (1<=x<y<=255)
* here x and y is specified in main()
* method's arguments.
* In winOS blank and dot can't be used
* in a machinename.
* Notice, for example, number 192 in law
* IP is -64( it is just <code>(byte)192</code> Wink

.
* Because law IP use byte numbers.
*/
public class GainMacNamesInLAN {
private int startIP4th = 1;
private int endIP4th = 255;
private int macNums = 0;
private int IP4th = 1;
private int sleepedExplorerNums = 0;
private int explorerNums = 0;
private long startExplorerTime = 0L;
private long endExplorerTime = 0L;

private class PrintEndStatus extends Thread {
private boolean runFlag = false;

public void run() {
while (true) {
if (runFlag) {
if (sleepedExplorerNums == explorerNums) {
endExplorerTime = System.currentTimeMillis();
printEndInfo();
runFlag = false;
System.exit(1);
}
} else {
sleep();
}
}
}

public void start() {
if (!runFlag) {
runFlag = true;
super.start();
}
}

public void sleep() {
try {
Thread.sleep(100000);
} catch (InterruptedException e) {
}
}
} // end class

private class IPExploreThread extends Thread {
private boolean runFlag = false;
private String hostname = null;
private int nowIP4th = 1;

public void run() {
while (true) {
if (runFlag) {
nowIP4th = getNextIP4th();
if (nowIP4th == 0) {
runFlag = false;
addSleepExplorerNums();
} else {
try {
hostname =
InetAddress
.getByAddress(
new byte[] {
-64,
-88,
0,
(byte) nowIP4th })
.getHostName();
} catch (UnknownHostException e) {
}
if (hostname.length() > 10
&& hostname.substring(0, 4).equals("192.")) {
} else {
System.out.println(
hostname + " / 192.168.0." + nowIP4th);
addMacNums();
}
}
} else {
sleep();
}
}
}

public void start() {
if (!runFlag) {
runFlag = true;
super.start();
}
}

public void sleep() {
try {
Thread.sleep(1000000);
} catch (InterruptedException e) {
}
}

} //end class

private void addMacNums() {
macNums++;
}

private void addSleepExplorerNums() {
sleepedExplorerNums++;
}

private void printStartInfo() {
System.out.println(
"\n\n********** Welcome to use IP Explorer version1.0 ***********");
System.out.println(
"Start exploring, using " + explorerNums + " explorers...\n");
}

private void printEndInfo() {
System.out.println(
"\nIP exploring process is finished.\nTotal "
+ macNums
+ " machines between 192.168.0."
+ startIP4th
+ " to 192.168.0."
+ endIP4th
+ " .");
System.out.println(
"Waste time: "
+ (endExplorerTime - startExplorerTime) / 1000L
+ " seconds.");
System.out.println(
"************************* alin&ASS *************************");
}

private synchronized int getNextIP4th() {
if (IP4th > endIP4th) {
return 0;
}
/我要记住下行这样写是可以的
return IP4th++;
}

/**
* Initialize explorer.
* @param startAddress start IP's fourth segment
* @param endAddress end IP's fourth segment
* @param threadNums explorer nums
*/
private void startIPExploreThreadBetween(
int startAddress,
int endAddress,
int threadNums) {
startIP4th = startAddress;
IP4th = startIP4th;
endIP4th = endAddress;
int IPNums = endIP4th - startIP4th + 1;
if (IPNums < threadNums) {
explorerNums = IPNums;
} else {
explorerNums = threadNums;
}
printStartInfo();
startExplorerTime = System.currentTimeMillis();
for (int i = 0; i < explorerNums; i++) {
new IPExploreThread().start();
}
new PrintEndStatus().start();
}

public static void main(String[] args) {
GainMacNamesInLAN alinLAN = new GainMacNamesInLAN();
if (args.length == 3) {
alinLAN.startIPExploreThreadBetween(
Integer.parseInt(args[0]),
Integer.parseInt(args[1]),
Integer.parseInt(args[2]));
} else {
alinLAN.startIPExploreThreadBetween(1, 50, 10);
}
}
}
－－－－－－－－－－－－－－－－－－－－－－－－

>java GainMacNamesInLAN 1 255 20
在我机子上的结果：
********** Welcome to use IP Explorer version1.0 ***********
Start exploring, using 20 explorers...

SK.mshome.net / 192.168.0.3
hong-7i9pfrfq32.mshome.net / 192.168.0.10
yangcat-1314.mshome.net / 192.168.0.1
ass / 192.168.0.2
hongmo.mshome.net / 192.168.0.34
lubing.mshome.net / 192.168.0.93
legend-qxanppz6.mshome.net / 192.168.0.121
jiangzuen.mshome.net / 192.168.0.129
zhoulian.mshome.net / 192.168.0.140
yangkefeng.mshome.net / 192.168.0.141
supu-comp.mshome.net / 192.168.0.145
fuqianjie.mshome.net / 192.168.0.155
fangbin.mshome.net / 192.168.0.161
jtime.mshome.net / 192.168.0.191

IP exploring process is finished.
Total 14 machines between 192.168.0.1 to 192.168.0.255 .
Waste time: 124 seconds.
************************* alin&ASS *************************

4.Re:求助(在局域网内如何获得所有网络计算机的名字和ip) [Re: cqlgc]	Copy to clipboard
Posted by: cqlgc Posted on: 2003-11-24 13:12 getByAddress()时怎么用的，那个byte[] 参数是什么意思。例如，如何得到IP地址为192.168.0.100 的计算机的名字。

5.Re:求助(在局域网内如何获得所有网络计算机的名字和ip) [Re: cqlgc]	Copy to clipboard
Posted by: nothing Posted on: 2003-11-24 13:24 http://java.sun.com/j2se/1.4.2/docs/api/java/net/InetAddress.html

6.Re:求助(在局域网内如何获得所有网络计算机的名字和ip) [Re: cqlgc]	Copy to clipboard
Posted by: alin_ass Posted on: 2003-11-24 22:51 用(byte)转型 192－－－》－64 168－－－》－88 .... String hostname = InetAddress .getByAddress( new byte[] { -64, -88, 0, 100}) .getHostName();

7.Re:求助(在局域网内如何获得所有网络计算机的名字和ip) [Re: cqlgc]	Copy to clipboard
Posted by: alin_ass Posted on: 2003-11-24 22:55 可是如果没找到它会不停找，估计要半分钟多才返回失败(就是主机名为ip), 我不知道怎么改失败时间，只好用多线程了...

8.Re:求助(在局域网内如何获得所有网络计算机的名字和ip) [Re: cqlgc]

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Posted by: alin_ass
Posted on: 2003-11-26 19:05

问:

为什么在Windows平台上用Naming.lookup来获取远程RMI对象时会很慢?

答:

机器的网络设置不正确很可能会引起该问题的发生.

RMI使用了Java网络类,特别是java.net.InetAddress类,它将查询TCP/IP的主机名, 包括IP地址到主机名的映射和主机名到IP地址的映射.在Windows平台,这种查询功能是由本地的Windows Socket库来实现的. 因此延时是发生在Windows库中,而非RMI中.

如果你的机器设置成使用DNS,问题通常是DNS服务器查不到主机名,你所发现的延时是DNS查询的延时. 请尝试将RMI通信中涉及到的所有主机名/IP地址加到本地文件 winntsystem32driversetchosts或windowshosts中. 格式如下:

IP地址主机名

如此设置应当可以明显地减少查询所花的时间.