网络通显示，不通不显示(由于java运行在服务端，所以测试的其实是服务端的上网情况）

package share.tools;

import java.awt.Toolkit;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class NetworkManagement implements Runnable {
private int htmlCodeSize;
private int sleepMillisecond;
private int sleepMillisecondWhenNetWorkUnLinked;
private boolean isSpontaneousNotice;
private static boolean networkIsLinked;
private Thread thread = new Thread(this);
private Toolkit toolkit;
private String[] urls;

public NetworkManagement() {
this.urls = new String[]{"http://weather.265.com/weather.htm", "http://weather.qq.com/inc/ss258.htm"};
this.htmlCodeSize = 50;
this.sleepMillisecond = 5000;
this.sleepMillisecondWhenNetWorkUnLinked = 10000;
this.toolkit = Toolkit.getDefaultToolkit();
thread.start();
}
public void setURLs(String[] urls) {
if (urls != null && urls.length > 0) {
this.urls = urls;
}
}
public void setHtmlCodeSize(int htmlCodeSize) {
if (htmlCodeSize > 0) {
this.htmlCodeSize = htmlCodeSize;
}
}
public void isSpontaneousNotice(boolean isSpontaneousNotice) {
this.isSpontaneousNotice = isSpontaneousNotice;
}
public void setSleepMillisecont(int sleepMillisecont) {
if (sleepMillisecont > 100) {
this.sleepMillisecond = sleepMillisecont;
}
}
public void setSleepMillisecondWhenNetWorkUnLinked(int sleepMillisecont) {
if (sleepMillisecont > 100) {
this.sleepMillisecondWhenNetWorkUnLinked = sleepMillisecont;
}
}
public static boolean IsNetWordLinking() {
return NetworkManagement.networkIsLinked;
}

public void run() {
while (true) {
try {
this.isNetWorkLinked();
if (!NetworkManagement.networkIsLinked) {
this.isPrintMessage(this.isSpontaneousNotice);
Thread.sleep(this.sleepMillisecondWhenNetWorkUnLinked);
}
// System.out.println(NetworkManagement.IsNetWordLinking());
Thread.sleep(this.sleepMillisecond);
} catch (Exception e) {
}
}
}

private boolean canGetHtmlCode(String httpUrl) {
String htmlCode = "";
try {
InputStream in;
URL url = new java.net.URL(httpUrl);
HttpURLConnection connection = (HttpURLConnection) url
.openConnection();
connection = (HttpURLConnection) url.openConnection();
connection.setRequestProperty("User-Agent", "Mozilla/4.0");
connection.connect();
in = connection.getInputStream();
byte[] buffer = new byte[this.htmlCodeSize];
in.read(buffer);
htmlCode = new String(buffer);
} catch (Exception e) {
}
if (htmlCode == null || htmlCode.equals("")) {
return false;
}
return true;
}

private void isNetWorkLinked() {
boolean tempIsNetWorkLinked = false;
for (int urlsCount = 0; urlsCount < this.urls.length; urlsCount++) {
if (this.canGetHtmlCode(this.urls[urlsCount])) {
tempIsNetWorkLinked = true;
break;
}
}
NetworkManagement.networkIsLinked = tempIsNetWorkLinked;
}
private void isPrintMessage(boolean isPrint) {
if (isPrint) {
// toolkit.beep();
StringBuffer message = new StringBuffer();
message.append("------------->");
message.append("�����网络中断, ");
message.append(this.sleepMillisecondWhenNetWorkUnLinked);
message.append(" 毫秒后再次检测!<-------------");
System.out.println(message.toString());
}

}
public static void main(String[] args) {
NetworkManagement n = new NetworkManagement();
n.isSpontaneousNotice(true);
}
}
--------------------------------------

jsp文件：

<th width="459" rowspan="2" scope="col" align="right">

<iframe id=tq1 style="z-index:2;position:relative;margin-right:0px
" src='http://weather.qq.com/inc/ss258.htm' id='ifm2' width='41%' height='90%' marginwidth='0' marginheight='0' hspace='0' vspace='0' frameborder='0' scrolling='NO'></iframe>
<FRAMESET border=0 frameSpacing=0 frameBorder=NO >
<iframe id=tq2 style="z-index:1;position:relative;
margin-right:0px" align="right" src="http://weather.265.com/weather.htm" width="42%" height="100%" frameborder="no" border="1" marginwidth="0" marginheight="0" scrolling="no"></iframe>
</FRAMESET>
</th>
<%
share.tools.NetworkManagement n = new share.tools.NetworkManagement();

n.isSpontaneousNotice(true);
if(n.IsNetWordLinking())
{
%>

<script>
document.all.tq1.src="http://weather.qq.com/inc/ss258.htm";
document.all.tq2.src="http://weather.265.com/weather.htm";
</script>
<%
}else{%>
<script>
document.all.tq1.src="#";
document.all.tq2.src="#";
</script>
<%}%>