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题目要求：设计一段程序，要求用户输入一个IP地址和一个子网掩码，计算出这个网络的网络位、主机位、网络号(第一个地址)、广播地址、最大主机容纳量、可用起始地址、可用结束地址, 注意要判断用户输入的地址是否有效例如127的环回地址和主机位全为0或者全为1的IP地址。
附加要求: 要求用户输入一个合理的主机数量，程序对当前地址进行子网划分并输出所有网段和其子网掩码、最大融安主机数量。
看完了题目要求后我选择使用java来实现，结果截图如下:
那么, 上代码了!
[mw_shl_code=java,true]
package com.company;
import java.math.BigInteger;
import java.sql.PreparedStatement;
import java.util.Scanner;
public class HostTest {
public static void main(String[] args) {
//创建储存IP和掩码二进制地址的变量
BigInteger ip, mask;
//创建储存IP和掩码的数组
String[] szIP = new String[4];
String[] szMask = new String[4];
//初始化输入器
Scanner sc = new Scanner(System.in);
Println("#请输入合法的IPv4地址:");
try {
//从屏幕获取一行用户输入数据
String str = sc.nextLine();
//将输入的IP地址按.分割为4段
String[] tmpIP = str.split("\\.");
//如果没有4段就提示错误
if (tmpIP.length != 4) throw new Exception();
//将获分割的字符串储存到IP数组内
for (int i = 0; i < tmpIP.length; i++) szIP = tmpIP;
} catch (Exception e) {
Println("你输入的不是合法的IPv4地址!");
return;
}
//如果IP为127开头的本地地址则提示错误
if (szIP[0].equals("127")) {
Println("这不是一个有效地址!(127开头的为本地环回地址)");
return;
}
Println("#请输入合法的子网掩码:");
try {
//从屏幕获取一行用户输入数据
String str = sc.nextLine();
//将输入的子网掩码按.分割为4段
String[] tmpMask = str.split("\\.");
//如果没有4段就提示错误
if (tmpMask.length != 4) throw new Exception();
//将获分割的字符串储存到IP数组内
for (int i = 0; i < tmpMask.length; i++) szMask = tmpMask;
} catch (Exception e) {
Println("你输入的不是合法的子网掩码!");
return;
}
//IP地址位运算
ip = new BigInteger(Integer.toBinaryString(Integer.parseInt(szIP[0]) << 24), 2);
ip = ip.add(new BigInteger(Integer.toBinaryString(Integer.parseInt(szIP[1]) << 16), 2));
ip = ip.add(new BigInteger(Integer.toBinaryString(Integer.parseInt(szIP[2]) << 8), 2));
ip = ip.add(new BigInteger(Integer.toBinaryString(Integer.parseInt(szIP[3])), 2));
//子网掩码位运算
mask = new BigInteger(Integer.toBinaryString(Integer.parseInt(szMask[0]) << 24), 2);
mask = mask.add(new BigInteger(Integer.toBinaryString(Integer.parseInt(szMask[1]) << 16), 2));
mask = mask.add(new BigInteger(Integer.toBinaryString(Integer.parseInt(szMask[2]) << 8), 2));
mask = mask.add(new BigInteger(Integer.toBinaryString(Integer.parseInt(szMask[3])), 2));
//得到网络位
int netNum = countStr(mask.toString(2), "1");
//得到主机位
int hostNum = 32 - netNum;
//得到二进制网络位
String binaryNetAddress = ip.and(mask).toString(2);
//创建网络号数组
int[] netAddress = {
Integer.parseInt(binaryNetAddress.substring(0, 8), 2),
Integer.parseInt(binaryNetAddress.substring(8, 16), 2),
Integer.parseInt(binaryNetAddress.substring(16, 24), 2),
Integer.parseInt(binaryNetAddress.substring(24, 32), 2)
};
//得到二进制网络位并进行判断是否全0或者全1
String ipNetBits = ip.toString(2).substring(0, netNum);
if (countStr(ipNetBits, "1") == 0 || countStr(ipNetBits, "1") == 0) {
Println("这不是一个有效的IP!(网络位不得全为0或者1)");
return;
}
//得到最大主机数
final int MAX_HOSTS = (int) (Math.pow(2, hostNum) - 2);
//创建网络广播地址数组
int[] netBroatcastAddress = new int[4];
netBroatcastAddress[0] = netAddress[0];
netBroatcastAddress[1] = netAddress[1];
netBroatcastAddress[2] = netAddress[2];
netBroatcastAddress[3] = netAddress[3];
//开始计算网络广播地址
int tmpNum = MAX_HOSTS + 2 - 1;
while (tmpNum > 0) {
netBroatcastAddress[3]++;
tmpNum--;
if (netBroatcastAddress[1] > 255) {
netBroatcastAddress[0]++;
netBroatcastAddress[1] = 0;
}
if (netBroatcastAddress[2] > 255) {
netBroatcastAddress[1]++;
netBroatcastAddress[2] = 0;
}
if (netBroatcastAddress[3] > 255) {
netBroatcastAddress[2]++;
netBroatcastAddress[3] = 0;
}
}
//创建主机起始地址数组
int[] startHostAddress = new int[4];
startHostAddress[0] = netAddress[0];
startHostAddress[1] = netAddress[1];
startHostAddress[2] = netAddress[2];
startHostAddress[3] = netAddress[3];
//计算主机开始地址
boolean carry = true;
while (carry) {
startHostAddress[3]++;
if (startHostAddress[3] == 255) {
startHostAddress[2]++;
startHostAddress[3] = 0;
continue;
}
if (startHostAddress[2] == 255) {
startHostAddress[1]++;
startHostAddress[2] = 0;
continue;
}
if (startHostAddress[1] == 255) {
startHostAddress[0]++;
startHostAddress[1] = 0;
continue;
}
carry = false;
}
//创建主机结束地址数组
int[] endHostAddress = new int[4];
endHostAddress[0] = netBroatcastAddress[0];
endHostAddress[1] = netBroatcastAddress[1];
endHostAddress[2] = netBroatcastAddress[2];
endHostAddress[3] = netBroatcastAddress[3];
//计算主机结束地址
carry = true;
while (carry) {
endHostAddress[3]--;
if (endHostAddress[3] == 0) {
endHostAddress[2]--;
endHostAddress[3] = 255;
continue;
}
if (endHostAddress[2] == 0) {
endHostAddress[1]--;
endHostAddress[2] = 255;
continue;
}
if (endHostAddress[1] == 0) {
endHostAddress[0]--;
endHostAddress[1] = 255;
continue;
}
carry = false;
}
//输出当前地址
Println(String.format("IP地址:%s.%s.%s.%s", szIP[0], szIP[1], szIP[2], szIP[3]));
Println(String.format("掩码地址:%s.%s.%s.%s", szMask[0], szMask[1], szMask[2], szMask[3]));
Println(String.format("网络位:%s", netNum));
Println(String.format("主机位:%s", hostNum));
Println(String.format("网络号:%d.%d.%d.%d", netAddress[0], netAddress[1], netAddress[2], netAddress[3]));
Println(String.format("广播地址:%d.%d.%d.%d", netBroatcastAddress[0], netBroatcastAddress[1], netBroatcastAddress[2], netBroatcastAddress[3]));
Println(String.format("最大容纳主机:%s", MAX_HOSTS));
Println(String.format("起始地址:%d.%d.%d.%d", startHostAddress[0], startHostAddress[1], startHostAddress[2], startHostAddress[3]));
Println(String.format("结束地址:%d.%d.%d.%d\n", endHostAddress[0], endHostAddress[1], endHostAddress[2], endHostAddress[3]));
Println("请输入有多少台主机需要划分子网(整数):");
int hosts = sc.nextInt();
sc.close();
//计算分配的子网主机位
int subHostNum = 1;
while (Math.pow(2, subHostNum) <= hosts) {
subHostNum++;
}
//当前子网地址数(包括网络号和广播号)
int subAddressNum = (int) Math.pow(2, subHostNum);
//拼接二进制子网掩码
StringBuilder sb = new StringBuilder();
for (int i = 0; i < (32 - subHostNum); i++) sb.append("1");
for (int i = 0; i < subHostNum; i++) sb.append("0");
//得到子网掩码
int[] subMask = {
Integer.parseInt(sb.toString().substring(0, 8), 2),
Integer.parseInt(sb.toString().substring(8, 16), 2),
Integer.parseInt(sb.toString().substring(16, 24), 2),
Integer.parseInt(sb.toString().substring(24, 32), 2)
};
//当前网络可划分多少个子网
int subNetNum = (MAX_HOSTS + 2) / subAddressNum;
//循环输出所有子网段
int[] subNetAddress = new int[4];
subNetAddress[0] = netAddress[0];
subNetAddress[1] = netAddress[1];
subNetAddress[2] = netAddress[2];
subNetAddress[3] = netAddress[3];
for (int i = 0; i < subNetNum; i++) {
System.out.println(String.format("[子网编号%d]%d.%d.%d.%d 掩码:%d.%d.%d.%d 最大容纳%d台主机", i,
subNetAddress[0], subNetAddress[1], subNetAddress[2], subNetAddress[3],
subMask[0], subMask[1], subMask[2], subMask[3], (subAddressNum-2)));
for(int j =0; j < (subAddressNum-1); j++) {
carry = true;
while (carry) {
subNetAddress[3]++;
if (subNetAddress[3] == 256) {
subNetAddress[2]++;
subNetAddress[3] = 0;
continue;
}
if (subNetAddress[2] == 256) {
subNetAddress[1]++;
subNetAddress[2] = 0;
continue;
}
if (subNetAddress[1] == 256) {
subNetAddress[0]++;
subNetAddress[1] = 0;
continue;
}
carry = false;
}
}
subNetAddress[3]++;
if (subNetAddress[3] == 256) {
subNetAddress[2]++;
subNetAddress[3] = 0;
}
}
}
/*
* 替换System.out.println()函数
* */
static void Println(String msg) {
System.out.println(msg);
}
/*
* 查找字符串中某个字符串出现的次数
* str: 被查找的字符串
* sToFind: 查找的字符串
* */
static int countStr(String str, String sToFind) {
int num = 0;
while (str.contains(sToFind)) {
str = str.substring(str.indexOf(sToFind) + sToFind.length());
num++;
}
return num;
}
}
[/mw_shl_code]
Felix 2020年6月12日 19:40 |
