IP地址与数字相互转换

/**  
     * ip地址转成整数.  
     * @param ip  
     * @return  
     */  
    public static long ip2long(String ip) {   
        String[] ips = ip.split("[.]");   
        long num =  16777216L*Long.parseLong(ips[0]) + 65536L*Long.parseLong(ips[1]) + 256*Long.parseLong(ips[2]) + Long.parseLong(ips[3]);   
        return num;   
    }   
       
    /**  
     * 整数转成ip地址.  
     * @param ipLong  
     * @return  
     */  
    public static String long2ip(long ipLong) {   
        //long ipLong = 1037591503;   
        long mask[] = {0x000000FF,0x0000FF00,0x00FF0000,0xFF000000};   
        long num = 0;   
        StringBuffer ipInfo = new StringBuffer();   
        for(int i=0;i<4;i++){   
            num = (ipLong & mask[i])>>(i*8);   
            if(i>0) ipInfo.insert(0,".");   
            ipInfo.insert(0,Long.toString(num,10));   
        }   
        return ipInfo.toString();   
    }