利用纯真IP数据库,通过IP查地址[JAVA]

package cn.ialvin.util;   
import java.io.*;   
  
public class QQWry {   
    private String DbPath = "F:\\DB\\QQWry2.Dat";    //纯真IP数据库地址   
    private String Country, LocalStr;   
    private long IPN;   
    private int RecordCount, CountryFlag;   
    private long RangE, RangB, OffSet, StartIP, EndIP, FirstStartIP, LastStartIP, EndIPOff;   
    private RandomAccessFile fis;   
    private byte[] buff;   
       
    private long B2L(byte[] b) {   
        long ret = 0;   
        for (int i=0; i<b.length; i++) {   
            long t = 1L;   
            for (int j=0; j<i; j++) t = t * 256L;   
            ret += ((b[ i ]<0)?256+b[ i ]:b[ i ]) * t;   
        }   
        return ret;   
    }   
       
    private long ipToInt(String ip) {   
        String[] arr = ip.split("\\.");   
        long ret = 0;   
        for (int i=0; i<arr.length; i++) {   
            long l = 1;   
            for (int j=0; j<i; j++) l *= 256;   
            try {   
                ret += Long.parseLong(arr[arr.length-i-1]) * l;   

            } catch (Exception e) {   
                ret += 0;   
            }   
        }   
        return ret;   
    }   
       
    public void seek(String ip) throws Exception {   
        this.IPN = ipToInt(ip);   
        fis = new RandomAccessFile(this.DbPath, "r");   
        buff = new byte[4];   
        fis.seek(0);   
        fis.read(buff);   
        FirstStartIP = this.B2L(buff);   
        fis.read(buff);   
        LastStartIP = this.B2L(buff);   
        RecordCount = (int)((LastStartIP - FirstStartIP) / 7);   
        if (RecordCount <= 1) {   
            LocalStr = Country = "未知";   
            throw new Exception();   
        }   
           
        RangB = 0;   
        RangE = RecordCount;   
        long RecNo;   
           
        do {   
            RecNo = (RangB+RangE)/2;   
            getStartIP(RecNo);   
            if (IPN == StartIP) {