请用java 使用http://ftp.apnic.net/apnic/stats/apnic/delegated-apnic-latest 写一段拦截ip的代码

以下是使用 Java 实现拦截 IP 的代码：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class IPFilter {

    private List<String> ipList = new ArrayList<>();

    public IPFilter() {
        try {
            // 从 APNIC 下载 IP 地址段数据
            URL url = new URL("http://ftp.apnic.net/apnic/stats/apnic/delegated-apnic-latest");
            BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
            String line;
            while ((line = reader.readLine()) != null) {
                String[] parts = line.split("\\|");
                if (parts[2].equals("ipv4")) { // 只处理 IPv4 地址段
                    long start = Long.parseLong(parts[3]);
                    long end = start + Long.parseLong(parts[4]) - 1;
                    addIPRange(start, end);
                }
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void addIPRange(long start, long end) {
        for (long i = start; i <= end; i++) {
            ipList.add(longToIP(i));
        }
    }

    private String longToIP(long ip) {
        StringBuilder builder = new StringBuilder();
        for (int i = 0; i < 4; i++) {
            builder.insert(0, Long.toString(ip & 0xff));
            if (i < 3) {
                builder.insert(0, '.');
            }
            ip >>= 8;
        }
        return builder.toString();
    }

    public boolean isBlocked(String ip) {
        return ipList.contains(ip);
    }

}

可以使用 `IPFilter` 类来判断一个 IP 是否被阻止，例如：

IPFilter filter = new IPFilter();
if (filter.isBlocked("192.168.0.1")) {
    System.out.println("Blocked");
} else {
    System.out.println("Allowed");
}