如何用java实现qqwry功能

QQWry是一个中国大陆地区的IP数据库，用于将IP地址转换为地理位置信息。要实现QQWry功能，你需要下载QQWry的数据库文件，然后使用Java进行解析和查询。以下是一个简单的示例，说明如何使用Java实现QQWry功能：

1. 首先，从官方网站（http://www.ipip.net/）下载QQWry的数据库文件（通常为.dat文件）。

2. 将下载的.dat文件放入项目的资源文件夹中。

3. 创建一个Java类，如QQWryUtil，并编写以下代码：

import java.io.*;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.zip.CRC32;

public class QQWryUtil {
    private static final int MAX_IP_LENGTH = 15;
    private static final int DATABASE_HEADER_SIZE = 7;
    private static final int IP_ADDR_LENGTH = 4;
    private static final int RECORD_LENGTH = 3;

    private byte[] database;

    public QQWryUtil(String filePath) throws IOException {
        this.database = readDatabase(filePath);
    }

    private byte[] readDatabase(String filePath) throws IOException {
        try (FileChannel fileChannel = new FileInputStream(filePath).getChannel()) {
            long startOffset = DATABASE_HEADER_SIZE;
            long fileSize = fileChannel.size();
            byte[] buffer = new byte[RECORD_LENGTH];
            int records = (int) ((fileSize - startOffset) / RECORD_LENGTH);

            byte[] data = new byte[fileSize - DATABASE_HEADER_SIZE];
            fileChannel.read(ByteBuffer.wrap(data), startOffset);

            for (int i = 0; i < records; i++) {
                int recordStart = i * RECORD_LENGTH;
                int recordEnd = recordStart + RECORD_LENGTH;
                System.arraycopy(data, recordStart, buffer, 0, RECORD_LENGTH);

                int ipStart = getInt(buffer, 0);
                int ipEnd = getInt(buffer, 4);
                String ip = getIp(data, ipStart, ipEnd);
                int offset = getInt(buffer, 8);

                System.arraycopy(data, offset, data, recordStart, IP_ADDR_LENGTH);
            }

            return data;
        }
    }

    private int getInt(byte[] buffer, int offset) {
        return ((buffer[offset] & 0xFF) << 24) |
                ((buffer[offset + 1] & 0xFF) << 16) |
                ((buffer[offset + 2] & 0xFF) << 8) |
                (buffer[offset + 3] & 0xFF);
    }

    private String getIp(byte[] data, int start, int end) {
        StringBuilder sb = new StringBuilder();
        for (int i = start; i <= end; i += IP_ADDR_LENGTH) {
            sb.append(String.format("%d.%d.%d.%d",
                    getInt(data, i), getInt(data, i + 4), getInt(data, i + 8), getInt(data, i + 12)));
            if (i != end) {
                sb.append(",");
            }
        }
        return sb.toString();
    }

    public String getLocation(String ip) {
        if (database == null) {
            throw new IllegalStateException("Database not loaded.");
        }

        int index = search(ip);
        if (index == -1) {
            return "Unknown";
        }

        int offset = index * RECORD_LENGTH;
        String country = new String(database, offset + 4, 2);
        String region = new String(database, offset + 6, 2);
        String city = new String(database, offset + 8, 2);
        String isp = new String(database, offset + 10, 4);

        return String.format("Country: %s, Region: %s, City: %s, ISP: %s", country, region, city, isp);
    }

    private int search(String ip) {
        long startOffset = DATABASE_HEADER_SIZE;
        long fileSize = database.length;
        int left = 0;
        int right = (int) (fileSize - DATABASE_HEADER_SIZE) - MAX_IP_LENGTH;

        while (left <= right) {
            int mid = left + (right - left) / 2;
            int cmp = compareIp(database, startOffset + mid, ip);

            if (cmp == 0) {
                return mid;
            } else if (cmp < 0) {
                left = mid + 1;
            } else {
                right = mid - 1;
            }
        }

        return -1;
    }

    private int compareIp(byte[] data, int start, String ip) {
        long ipValue = 0;
        for (int i = 0; i < IP_ADDR_LENGTH; i++) {
            ipValue = (ipValue << 8) | (data[start + i] & 0xFF);
        }

        long targetValue = 0;
        for (int i = 0; i < IP_ADDR_LENGTH; i++) {
            targetValue = (targetValue << 8) | (ip.charAt(i) - '0');
        }

        return (int) (ipValue - targetValue);
    }

    public static void main(String[] args) {
        try {
            QQWryUtil qqWryUtil = new QQWryUtil("path/to/your/qqwry.dat");
            String ip = "8.8.8.8";
            String location = qqWryUtil.getLocation(ip);
            System.out.println("IP: " + ip + ", Location: " + location);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

4. 修改main方法中的path/to/your/qqwry.dat为你的QQWry数据库文件的实际路径。

5. 运行程序，输入一个IP地址，你将看到相应的地理位置信息。

请注意，这个示例仅用于演示目的，实际应用中可能需要对代码进行调整和优化。同时，QQWry数据库文件受到版权保护，使用时请注意遵守相关法律法规。