通过jjava代码， 获取Linux中ip地址和网关，及dns

可以使用Java代码来获取Linux中的IP地址、网关和DNS信息。以下是示例代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class NetworkInfo {

    public static void main(String[] args) {
        try {
            String ip = getIPAddress();
            String gateway = getGateway();
            String[] dns = getDNS();

            System.out.println("IP Address: " + ip);
            System.out.println("Gateway: " + gateway);
            System.out.print("DNS: ");
            for (String server : dns) {
                System.out.print(server + " ");
            }
            System.out.println();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static String getIPAddress() throws IOException {
        Process process = Runtime.getRuntime().exec("ifconfig | grep inet | awk '{print $2}' | cut -d':' -f2");
        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String line = reader.readLine();
        return line;
    }

    public static String getGateway() throws IOException {
        Process process = Runtime.getRuntime().exec("ip route | grep default | awk '{print $3}'");
        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String line = reader.readLine();
        return line;
    }

    public static String[] getDNS() throws IOException {
        Process process = Runtime.getRuntime().exec("cat /etc/resolv.conf | grep nameserver | awk '{print $2}'");
        BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        String line;
        StringBuilder output = new StringBuilder();
        while ((line = reader.readLine()) != null) {
            output.append(line);
            output.append(" ");
        }
        return output.toString().trim().split(" ");
    }
}

该代码使用 `Runtime.exec()` 方法执行系统命令，并使用 `BufferedReader` 读取命令输出。 `getIPAddress()` 方法获取IP地址， `getGateway()` 方法获取网关， `getDNS()` 方法获取DNS服务器的IP地址。注意，这些命令在Linux系统上执行，所以该代码只能在Linux系统上运行。