java实现linux中现有ip和新增ip是否在一个网段内

在Java中检查两个IP地址是否属于同一个网络段，通常涉及到网络地址的计算和比较。你可以通过IP地址的掩码（subnet mask）来判断它们是否在同一网络。下面是一个简单的步骤：

1. **获取IP地址和掩码（子网掩码）**: 对于给定的IPv4地址，你需要获取其对应的二进制形式，并计算出它的网络部分（包括前缀长度）和主机部分。

import java.net.InetAddress;
import java.util.regex.Pattern;

public class IPUtils {
    private static final Pattern IP_PATTERN = Pattern.compile("^([0-9]{1,3}\\.){3}[0-9]{1,3}$");
    
    public static boolean isSameNetwork(String ip1, String ip2, String subnet) throws Exception {
        if (!IP_PATTERN.matcher(ip1).matches() || !IP_PATTERN.matcher(ip2).matches()) {
            throw new IllegalArgumentException("Invalid IP address format");
        }
        
        InetAddress addr1 = InetAddress.getByName(ip1);
        InetAddress addr2 = InetAddress.getByName(ip2);
        byte[] netmask = InetAddress.getByName(subnet).getHostAddress().getBytes();
        
        int prefixLength = getPrefixLength(netmask);
        
        byte[] network1 = addr1.getAddress();
        byte[] network2 = addr2.getAddress();
        
        for (int i = 0; i < prefixLength; i++) {
            network1[i] &= netmask[i];
            network2[i] &= netmask[i];
        }

        return Arrays.equals(network1, network2);
    }
    
    private static int getPrefixLength(byte[] netmask) {
        int prefixLength = 0;
        while (prefixLength < 32 && netmask[prefixLength] == 255) {
            prefixLength++;
        }
        return prefixLength;
    }
}

**如何使用：**

String existingIp = "192.168.1.1";
String newIp = "192.168.1.2";
String subnet = "255.255.255.0"; // 或者其他子网掩码

try {
    boolean inSameSegment = IPUtils.isSameNetwork(existingIp, newIp, subnet);
    System.out.println(inSameSegment ? "两个IP在同一个网段" : "不在同一个网段");
} catch (IllegalArgumentException | UnknownHostException e) {
    e.printStackTrace();
}