如何使用Java获取在同一网络(子网)中连接的IP列表

要在同一网络（子网）中使用Java获取连接的IP列表，您可以使用以下方法：

获取本地IP地址：

import java.net.InetAddress;
import java.net.UnknownHostException;

public class IPAddressExample {
    public static void main(String[] args) {
        try {
            InetAddress ip = InetAddress.getLocalHost();
            System.out.println("本地IP地址：" + ip.getHostAddress());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

获取子网掩码：

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;

public class SubnetMaskExample {
    public static void main(String[] args) {
        try {
            InetAddress ip = InetAddress.getLocalHost();
            NetworkInterface networkInterface = NetworkInterface.getByInetAddress(ip);
            int subnetMask = 0;
            for (InterfaceAddress address : networkInterface.getInterfaceAddresses()) {
                if (address.getAddress().getHostAddress().equals(ip.getHostAddress())) {
                    subnetMask = address.getNetworkPrefixLength();
                    break;
                }
            }
            System.out.println("子网掩码：" + subnetMask);
        } catch (SocketException | UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

获取网络中的所有IP地址：

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;

public class NetworkIPAddressesExample {
    public static void main(String[] args) {
        List<String> ipAddresses = new ArrayList<>();
        try {
            InetAddress ip = InetAddress.getLocalHost();
            NetworkInterface networkInterface = NetworkInterface.getByInetAddress(ip);
            int subnetMask = 0;
            for (InterfaceAddress address : networkInterface.getInterfaceAddresses()) {
                if (address.getAddress().getHostAddress().equals(ip.getHostAddress())) {
                    subnetMask = address.getNetworkPrefixLength();
                    break;
                }
            }
            int networkPrefixLength = subnetMask;
            int addressLength = ip.getAddress().length;
            byte[] networkAddress = new byte[addressLength];
            byte[] subnetMaskBytes = new byte[addressLength];
            for (int i = 0; i< addressLength; i++) {
                networkAddress[i] = (byte) (ip.getAddress()[i] & (subnetMask >= 8 ? 0xFF : (1<< subnetMask) - 1));
                subnetMaskBytes[i] = (byte) (subnetMask >= 8 ? 0xFF : (1<< subnetMask) - 1);
                subnetMask -= 8;
            }
            InetAddress network = InetAddress.getByAddress(networkAddress);
            InetAddress broadcast = InetAddress.getByAddress(subnetMaskBytes);
            System.out.println("网络地址：" + network.getHostAddress());
            System.out.println("广播地址：" + broadcast.getHostAddress());
            for (int i = 1; i < 255; i++) {
                InetAddress address = InetAddress.getByAddress(new byte[]{networkAddress[0], networkAddress[1], networkAddress[2], (byte) i});
                if (!address.getHostAddress().equals(ip.getHostAddress())) {
                    ipAddresses.add(address.getHostAddress());
                }
            }
            System.out.println("网络中的IP地址列表：");
            ipAddresses.forEach(System.out::println);
        } catch (SocketException | UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

这个示例代码将获取本地IP地址、子网掩码、网络地址和广播地址，并输出网络中的所有IP地址列表。请注意，这个示例代码仅适用于小型网络，因为它只检查了1到254之间的IP地址。对于大型网络，您可能需要使用其他方法来扫描网络中的所有IP地址。