Question

我的电脑连接到2个不同的接口，可以访问互联网（有线连接和wifi连接到我的智能手机，具有移动访问权限，用于有线连接丢失的情况）。

当有线连接有互联网连接时，我在DOS提示符下手动断开另一个（移动）连接：

netsh wlan disconnect interface="Wi-Fi"

现在，如果我可以通过有线网络连接到达任何网站，我会每分钟检查一次。

一旦失败，java将再次连接到Wi-Fi连接，以便减少互联网连接：

但问题出现了：一旦有线互联网重新启动并运行，我希望java再次通过该接口地址自动连接并断开＆＃34; Wi-Fi＆＃34; （限制成本......）。

我不知道是否可以连接到以预定义IP地址开头的网址，以便找出有线连接何时再次联机。

Answer 1

最后我自己找到了一个解决方案，如下面的代码所示（此代码作为测试运行，在具有有线和无线连接的桌面上启动，自动导致关闭移动连接，然后手动断开连接有线连接，再次自动打开移动连接。一旦手动重新连接有线连接，移动连接将再次断开连接）。

package testingPackage;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.Socket;
import java.util.Enumeration;
public class TestInternet {
public static void main(String[] args) {
int internet = 1;
int counter = 0;
while(counter<10){
    counter = counter + 1;
    int connections = 0;
    Socket[] soc = new Socket[10];
    try{
        NetworkInterface nif = NetworkInterface.getByName("eth1");
        //the right name of the wired internet can be found with following code in between  /* … */
        /*
        Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();
            while (interfaces.hasMoreElements()) {
            NetworkInterface interf = interfaces.nextElement();
            if (interf.isUp() && !interf.isLoopback()) {
                List<InterfaceAddress> adrs = interf.getInterfaceAddresses();
                for (Iterator<InterfaceAddress> iter = adrs.iterator(); iter.hasNext();) {
                    InterfaceAddress adr = iter.next();
                    InetAddress inadr = adr.getAddress();
                    if (inadr instanceof Inet4Address){
                        NetworkInterface nif1 = NetworkInterface.getByInetAddress(inadr);
                        System.out.println("L30 = "+nif1);
                    } 
                }
            }
        } 
        */
        Enumeration<InetAddress> nifAddresses = nif.getInetAddresses();
        while (nifAddresses.hasMoreElements()){
            soc[connections] = new java.net.Socket();
            soc[connections].bind(new InetSocketAddress(nifAddresses.nextElement(), 0));
            connections = connections + 1;
        }
        soc[0].connect(new InetSocketAddress("www.google.com", 80));
        if(internet==0){
            System.out.println("Internet is BACK, throw out the mobile internet now !");
            try{
                Runtime.getRuntime().exec(new String[]{"netsh", "wlan", "disconnect", "interface=Wi-Fi"});
                internet = 1;
            }
            catch (Exception e2) {System.out.println("Warning : Could not disconnect the mobile network !");  }
        }
        else{
            System.out.println("Internet is UP");
        }
    }
    catch (Exception e) {
        System.out.println("enumeration failed");connections  = 0;
        System.out.println("Internet is still DOWN, connect to mobile internet now !");
        connections  = 0;
        internet = 0;
        //find SSID name, profile name and interface name of the wired and wireless network in DOS :
            //netsh wlan show networks : returns the SSID name XXXX
            //netsh wlan show profile (REQUIRED): returns the profile name YYYY
            //netsh wlan show interfaces : returns the interface name
        try{
            Runtime.getRuntime().exec(new String[]{"netsh", "wlan", "connect","ssid=XXXX", "name=YYYY", "interface=Wi-Fi"});
        }
        catch (Exception e2) {System.out.println("Warning : no internet ! Could not connect to mobile network !");  }
    }
    System.out.println("number of wired connections = "+connections);
    try {Thread.sleep(10000);} 
    catch (InterruptedException e) {System.out.println("no sleep"); }
}

} }

如何通过某个界面地址检查互联网是否已启动？

1 个答案: