一个ip地址用字符串保存,长度为(7-15)也就是(14-30bytes),而用int保存只需要4bytes,所以下面的代码:

​
    /**
     * ip字符串转整数
     * ip是.分割的整数字符串,按照r进制转十进制的规律,按权相加求和,这里的权是256.
     * @param ip
     * @return
     */
        public int ip2Int(String ip){
        if(null == ip || "".equals(ip.trim()) || !checkIP(ip)) return 0;
        String[] ipStrs = ip.split("\\.");//分割ip
        int result = 0;
        for(int i = 0;i < 4;i ++){
            Integer ipSubInteger = Integer.parseInt(ipStrs[i]);
            if(ipSubInteger > 255) {//正则验证不能为负数
                result = 0;
                break;
            }
            result += (ipSubInteger << (24 - i * 8));
        }
        return result;
    }
    
    /*正则验证ip*/
    private boolean checkIP(String ip){
        return ip.matches("\\d{1,3}(\\.\\d{1,3}){3}");
    }
    
    /**
     * 整数转ip
     * @param ip
     * @return
     */
    public String int2Ip(int ip){
        StringBuilder builder = new StringBuilder(String.valueOf(ip >>> 24));
        builder.append(".");
        builder.append(String.valueOf((ip & 0X00FFFFFF) >>> 16));
        builder.append(".");
        builder.append(String.valueOf((ip & 0X0000FFFF) >>> 8));
        builder.append(".");
        builder.append(String.valueOf(ip & 0X000000FF));
        return builder.toString();
    }

​