JAVA 检测网络是否为连通状态 ping

心已赠人 2022-01-14 11:17 1340阅读 0赞

要用java检测网络资源是否可用，我们可以采用以下两种方法：  
一种方法是调用ping命令，  
如：  
Process process= Runtime.getRuntime().exec("ping 192.168.0.5");  
InputStreamReader return = new InputStreamReader(process.getInputStream());  
LineNumberReader returnData = new LineNumberReader (return);  
  
String line="";  
while((line=returnData.readLine())!=null)\{  
System.out.println(line);  
\}  
通用对返回数据进行分析，来探测网络资源的可用性；  
这种方法有一个缺点：就是许多网络资源是不允许被ping的，从而针对这类资源无法探测。

(2008-07-28记)

Dos中的ping 命令能很方便的检测网络是否为连通状态.但是在java中,一直没有找到好的方法检来测网络是否为连通状态.无奈之余,想出了如下方法:

![None.gif][] package  com.roadway.edserver.util;  
![None.gif][]  
![None.gif][] import  java.awt.Toolkit;  
![None.gif][] import  java.io.InputStream;  
![None.gif][] import  java.net.HttpURLConnection;  
![None.gif][] import  java.net.URL;  
![ExpandedBlockStart.gif][] /\*\*  
![InBlock.gif][] \* @Description:本类开启一个线程检测网络是否连通  
![InBlock.gif][] \* @Author : 惠万鹏  
![InBlock.gif][] \* @Time :2008-1-10  
![ExpandedBlockEnd.gif][] \*/   
![ExpandedBlockStart.gif][] public   class  NetworkManagement  implements  Runnable  \{  
![InBlock.gif][]    private int htmlCodeSize;  
![InBlock.gif][]    private int sleepMillisecond;  
![InBlock.gif][]    private int sleepMillisecondWhenNetWorkUnLinked;  
![InBlock.gif][]    private boolean isSpontaneousNotice;  
![InBlock.gif][]    private static boolean networkIsLinked;  
![InBlock.gif][]    private Thread thread = new Thread(this);  
![InBlock.gif][]    private Toolkit toolkit;  
![InBlock.gif][]    private String\[\] urls;  
![InBlock.gif][]  
![ExpandedSubBlockStart.gif][]    public NetworkManagement() \{  
![ExpandedSubBlockStart.gif][]        this.urls = new String\[\]\{ "http://www.baidu.com", "http://www.google.cn"\};  
![InBlock.gif][]        this.htmlCodeSize = 50;  
![InBlock.gif][]        this.sleepMillisecond = 5000;  
![InBlock.gif][]        this.sleepMillisecondWhenNetWorkUnLinked = 10000;  
![InBlock.gif][]        this.toolkit = Toolkit.getDefaultToolkit();  
![InBlock.gif][]        thread.start();  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    public void setURLs(String\[\] urls) \{  
![ExpandedSubBlockStart.gif][]        if (urls != null && urls.length > 0) \{  
![InBlock.gif][]            this.urls = urls;  
![ExpandedSubBlockEnd.gif][]        \}  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    public void setHtmlCodeSize(int htmlCodeSize) \{  
![ExpandedSubBlockStart.gif][]        if (htmlCodeSize > 0) \{  
![InBlock.gif][]            this.htmlCodeSize = htmlCodeSize;  
![ExpandedSubBlockEnd.gif][]        \}  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    public void isSpontaneousNotice(boolean isSpontaneousNotice) \{  
![InBlock.gif][]        this.isSpontaneousNotice = isSpontaneousNotice;  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    public void setSleepMillisecont(int sleepMillisecont) \{  
![ExpandedSubBlockStart.gif][]        if (sleepMillisecont > 100) \{  
![InBlock.gif][]            this.sleepMillisecond = sleepMillisecont;  
![ExpandedSubBlockEnd.gif][]        \}  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    public void setSleepMillisecondWhenNetWorkUnLinked(int sleepMillisecont) \{  
![ExpandedSubBlockStart.gif][]        if (sleepMillisecont > 100) \{  
![InBlock.gif][]            this.sleepMillisecondWhenNetWorkUnLinked = sleepMillisecont;  
![ExpandedSubBlockEnd.gif][]        \}  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    public static boolean IsNetWordLinking() \{  
![InBlock.gif][]        return NetworkManagement.networkIsLinked;  
![ExpandedSubBlockEnd.gif][]    \}  
![InBlock.gif][]  
![ExpandedSubBlockStart.gif][]    public void run() \{  
![ExpandedSubBlockStart.gif][]        while (true) \{  
![ExpandedSubBlockStart.gif][]            try \{  
![InBlock.gif][]                this.isNetWorkLinked();  
![ExpandedSubBlockStart.gif][]                if (!NetworkManagement.networkIsLinked) \{  
![InBlock.gif][]                    this.isPrintMessage(this.isSpontaneousNotice);  
![InBlock.gif][]                    Thread.sleep(this.sleepMillisecondWhenNetWorkUnLinked);  
![ExpandedSubBlockEnd.gif][]                \}  
![InBlock.gif][]                System.out.println(NetworkManagement.IsNetWordLinking());  
![InBlock.gif][]                Thread.sleep(this.sleepMillisecond);  
![ExpandedSubBlockStart.gif][]            \} catch (Exception e) \{  
![ExpandedSubBlockEnd.gif][]            \}  
![ExpandedSubBlockEnd.gif][]        \}  
![ExpandedSubBlockEnd.gif][]    \}  
![InBlock.gif][]  
![ExpandedSubBlockStart.gif][]    private boolean canGetHtmlCode(String httpUrl) \{  
![InBlock.gif][]        String htmlCode = "";  
![ExpandedSubBlockStart.gif][]        try \{  
![InBlock.gif][]            InputStream in;  
![InBlock.gif][]            URL url = new java.net.URL(httpUrl);  
![InBlock.gif][]            HttpURLConnection connection = (HttpURLConnection) url  
![InBlock.gif][]                    .openConnection();  
![InBlock.gif][]            connection = (HttpURLConnection) url.openConnection();  
![InBlock.gif][]            connection.setRequestProperty("User-Agent", "Mozilla/4.0");  
![InBlock.gif][]            connection.connect();  
![InBlock.gif][]            in = connection.getInputStream();  
![InBlock.gif][]            byte\[\] buffer = new byte\[this.htmlCodeSize\];  
![InBlock.gif][]            in.read(buffer);  
![InBlock.gif][]            htmlCode = new String(buffer);  
![ExpandedSubBlockStart.gif][]        \} catch (Exception e) \{  
![ExpandedSubBlockEnd.gif][]        \}  
![ExpandedSubBlockStart.gif][]        if (htmlCode == null || htmlCode.equals("")) \{  
![InBlock.gif][]            return false;  
![ExpandedSubBlockEnd.gif][]        \}  
![InBlock.gif][]        return true;  
![ExpandedSubBlockEnd.gif][]    \}  
![InBlock.gif][]  
![ExpandedSubBlockStart.gif][]    private void isNetWorkLinked() \{  
![InBlock.gif][]        boolean tempIsNetWorkLinked = false;  
![ExpandedSubBlockStart.gif][]        for (int urlsCount = 0; urlsCount < this.urls.length; urlsCount\++) \{  
![ExpandedSubBlockStart.gif][]            if (this.canGetHtmlCode(this.urls\[urlsCount\])) \{  
![InBlock.gif][]                tempIsNetWorkLinked = true;  
![InBlock.gif][]                break;  
![ExpandedSubBlockEnd.gif][]            \}  
![ExpandedSubBlockEnd.gif][]        \}  
![InBlock.gif][]        NetworkManagement.networkIsLinked = tempIsNetWorkLinked;  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    private void isPrintMessage(boolean isPrint) \{  
![ExpandedSubBlockStart.gif][]        if (isPrint) \{  
![InBlock.gif][]            toolkit.beep();  
![InBlock.gif][]            StringBuffer message = new StringBuffer();  
![InBlock.gif][]            message.append("\------------->");  
![InBlock.gif][]            message.append("网络中断, ");  
![InBlock.gif][]            message.append(this.sleepMillisecondWhenNetWorkUnLinked);  
![InBlock.gif][]            message.append(" 毫秒后再次检测!<-------------");  
![InBlock.gif][]            System.out.println(message.toString());  
![ExpandedSubBlockEnd.gif][]        \}  
![InBlock.gif][]  
![ExpandedSubBlockEnd.gif][]    \}  
![ExpandedSubBlockStart.gif][]    public static void main(String\[\] args) \{  
![InBlock.gif][]        NetworkManagement n = new NetworkManagement();  
![InBlock.gif][]        n.isSpontaneousNotice(true);  
![ExpandedSubBlockEnd.gif][]    \}

![ExpandedBlockEnd.gif][]\}

转自：http://www.blogjava.net/hwpok/archive/2007/12/07/166121.html

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