用Java在1s左右测试网络的连接状态.java

* to ping ``, if there is no connection after 4s, then this
* method will return false, but you know, since the multi-thread will make
// ping `
connected = false;
new Thread(new Runnable() {
public void run() {
try {
Runtime runtime = Runtime.getRuntime();
Process p = runtime.exec("ping ");
InputStreamReader reader = new InputStreamReader(
p.getInpuheck whether the network is connected. this method will firstly check
* whether the network interfaces are all up and then make a system command
*/
public static boolean isNetworkConnected() {
int infCount = 0;
try {
// firstly check the network interfaces.
Enumeration<NetworkInterface> netints = NetworkInterface
} catch (IOException e) {
}
}
}).start();
// wait for 1000millsecond
Thread.sleep(1000);
// 在这次的旅行者系统，经常会因为网络的问题导致刷新速度很慢，经过一番摸索，终于实现了自己的测试方法，网上大部分用的都是URL来实现，当openConnection有返回结果时证明是连通的，但要是不连通，却要等很久。于是心想，其实这样处理这个问题，首先检查电脑的各个接口是否处于up的状态，如果没有处于up状态的接口，则肯定是不连通的，要是存在up的接口，再测试ping指令，在国内自然ping 最好。于是写出了下面这段代码：
buf.readLine(); // real output
connected = true;
buf.close();
reader.close();
infCount++;
}
}
// no available network interfaces
if (infCount == 0) {
// if needed.
return connected;
} catch (IOException | InterruptedException e) {
return false;
}
}
BufferedReader buf = new BufferedReader(reader);
buf.readLine(); // empty line
buf.readLine(); // prompt for this command
* some mistake. you would like to invoke this method twice to ensure there
* is no connection.
*
* @return true when the connection is established.
.getNetworkInterfaces();
while (netints.hasMoreElements()) {
NetworkInterface intf = netints.nextElement();
if (intf.isUp() && !intf.isLoopback()) {
// JOptionPane.showMessageDialog(null, "你似乎把网线拔掉了？");
return false;
}
// if there exist some active interface. test it