import java.io.BufferedReader;    import java.io.IOException;    import java.io.InputStream;    import java.io.InputStreamReader;        /**    * 判断网络连接状况.    * @author nagsh    *    */    public class NetState {            public boolean isConnect(){            boolean connect = false;            Runtime runtime = Runtime.getRuntime();            Process process;            try {                process = runtime.exec("ping " + "www.baidu.com");                InputStream is = process.getInputStream();                 InputStreamReader isr = new InputStreamReader(is);                 BufferedReader br = new BufferedReader(isr);                 String line = null;                 StringBuffer sb = new StringBuffer();                 while ((line = br.readLine()) != null) {                     sb.append(line);                 }                 System.out.println("返回值为:"+sb);                  is.close();                 isr.close();                 br.close();                     if (null != sb && !sb.toString().equals("")) {                     String logString = "";                     if (sb.toString().indexOf("TTL") > 0) {                         // 网络畅通                          connect = true;                    } else {                         // 网络不畅通                          connect = false;                    }                 }             } catch (IOException e) {                e.printStackTrace();            }             return connect;        }                public static void main(String[] args) {            NetState netState = new NetState();            System.out.println(netState.isConnect());            }        }