根据IP及编码位计算网络与广播地址,并返回可用IP数

比对计算137.0.222.0/23的网络及广播地址,并返回可用IP数

• 对IP及掩码位进行校验

public static void ipcheck(String host, String mask) throws Exception {
        if (!host.matches("^(1\\d{2}|2[0-4]\\d|25[0-5]|[1-9]\\d|[1-9])\\."
                + "(1\\d{2}|2[0-4]\\d|25[0-5]|[1-9]\\d|\\d)\\." + "(1\\d{2}|2[0-4]\\d|25[0-5]|[1-9]\\d|\\d)\\."
                + "(1\\d{2}|2[0-4]\\d|25[0-5]|[1-9]\\d|\\d)$")) {
            throw new Exception("IP地址不合规范");
        }
        if (!Pattern.compile("[0-9]*").matcher(mask).matches() || Integer.parseInt(mask)
                <= 0 || Integer.parseInt(mask) > 32) {
            throw new Exception("子网掩码位不合规范");
        }
    }

• 对掩码位进行计算

掩码位总共32位,转换为二进制就是32个1,掩码位23就是[11111111 11111111 11111110 00000000],对不满足32位的进行补0处理

/**
     * 计算掩码
     *
     * @param mask
     * @return 二进制数组如[11111111, 11111111, 11111111, 11111111]
     */
    public static String[] maskCode(int mask) {
        String[] strs = new String[4];
        StringBuffer maskBuff = new StringBuffer();
        int intergeBit = mask / 8;
        int remainderBit = mask % 8;
        for (int i = 0; i < intergeBit; i++) {
            strs[i] = "11111111";
        }
        switch (intergeBit) {
            case 0:
                for (int i = 0; i < remainderBit; i++) {
                    maskBuff.append("1");
                }
                strs[0] = remainderBit==0?"00000000":String.format("%-8d", Integer.parseInt(maskBuff.toString())).replace(" ", "0");
                strs[1] = "00000000";
                strs[2] = "00000000";
                strs[3] = "00000000";
                break;
            case 1:
                for (int i = 0; i < remainderBit; i++) {
                    maskBuff.append("1");
                }
                strs[1] = remainderBit==0?"00000000":String.format("%-8d", Integer.parseInt(maskBuff.toString())).replace(" ", "0");
                strs[2] = "00000000";
                strs[3] = "00000000";
                break;
            case 2:
                for (int i = 0; i < remainderBit; i++) {
                    maskBuff.append("1");
                }
                strs[2] = remainderBit==0?"00000000":String.format("%-8d", Integer.parseInt(maskBuff.toString())).replace(" ", "0");
                strs[3] = "00000000";
                break;
            case 3:
                for (int i = 0; i < remainderBit; i++) {
                    maskBuff.append("1");
                }
                strs[3] = remainderBit==0?"00000000":String.format("%-8d", Integer.parseInt(maskBuff.toString())).replace(" ", "0");
                break;
        }
        return strs;
    }

• 计算网络号

将IP与掩码进行与计算,得到网络号

/**
     * 计算网络
     *
     * @param host
     * @param mask
     * @return 10.0.0.1
     */
    public static String getNetWork(String host, String[] mask) {
        String[] hostArray = host.split("\\.");
        String[] networkArray = getIp(mask).split("\\.");
        StringBuffer netWork = new StringBuffer();
        for (int i = 0; i < hostArray.length; i++) {
            if (i == 0) {
                netWork.append(Integer.parseInt(hostArray[i]) & Integer.parseInt(networkArray[i]));
            } else {
                netWork.append(".").append(Integer.parseInt(hostArray[i]) & Integer.parseInt(networkArray[i]));
            }
        }
        return netWork.toString();
    }

• 计算广播地址

根据网络地址与掩码地址,转换为二进制后,掩码后面几位为0就是几位主机号,将网络地址的二进制数据截取到主机位,再拼接主机位,(注意此处要将0改成1)

/**
     * 计算广播地址
     *
     * @param host
     * @param mask
     * @return
     */
    public static String[] getRedio(String host, String mask) {
        StringBuffer networkbuff = new StringBuffer().append(getBinary(host).replaceAll("\\.", ""));
        StringBuffer maskbuff = new StringBuffer().append(getBinary(mask).replaceAll("\\.", ""));
        int hostlength = maskbuff.lastIndexOf("1");
        String[] redio = new String[4];
        StringBuffer redioBuff = new StringBuffer(networkbuff.substring(0, hostlength + 1));
        redioBuff.append(maskbuff.substring(hostlength + 1).replaceAll("0", "1"));
        redio[0] = redioBuff.substring(0, 8);
        redio[1] = redioBuff.substring(8, 16);
        redio[2] = redioBuff.substring(16, 24);
        redio[3] = redioBuff.substring(24, 32);
        return redio;
    }

• 可用IP数为2的(32-掩码位)次方-网络地址与广播地址

网络地址与广播地址之间为可用网络地址

 

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