java判断网络连接是否正常

/**
* 判断本机当前的网络状态是否联通
* 在这里主要用到中国天气信息，所以访问百度地址是否能够访问成功来判断当前的网络状态
*/
public static boolean isConnect() {
Runtime runtime = Runtime.getRuntime();
try {
Process 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);
}
is.close();
isr.close();
br.close();

if (null != sb && !sb.toString().equals("")) {
if (sb.toString().indexOf("TTL") > 0) {
//网络畅通
return true;
}
}
} catch (Exception e) {
e.printStackTrace();
}

return false;
}