算法 - 随机密码生成算法
【摘要】
算法 - 随机密码生成算法
import java.util.Random;
/**
* Created by 谭健 on 2017/10/16. 11:13.
* © All Rights ...
算法 - 随机密码生成算法
import java.util.Random;
/**
* Created by 谭健 on 2017/10/16. 11:13.
* © All Rights Reserved.
*/
public class Password {
public Password() {
}
// 提供强度的构造方法
public Password(int strengthLevel, int length) {
this.strengthLevel = strengthLevel;
this.length = length;
}
/**
* Password level config
* 1 level : only number
* 2 level : number and lowercase letters
* 3 level : number , lowercase letters , capital letters
* 4 level : number , lowercase letters , capital letters , special characters
*/
private int strengthLevel = 4;
// 需要的密码长度
private int length = 6;
private static final Random RANDOM = new Random();
// getter and setter
public int getLength() {
return length;
}
public void setLength(int length) {
this.length = length;
}
public int getStrengthLevel() {
return strengthLevel;
}
public void setStrengthLevel(int strengthLevel) {
this.strengthLevel = strengthLevel;
}
// 用char类型是因为char类型效率比数组方式要高
// 因为伪随机数random在nextInt()的时候会出现向更小的数偏离的情况，所以用一个randomMax来修正
private static final int randomMax = 100000000;
// 因为数组下标从0开始
private static final int index = 1;
// 一共26个字母
private static final int numberOfLetter = 26;
// ascii码表数字从48开始
private static final int nunberIndex = 48;
// 数组下标0-9代表10个数字
private static final int numberMax = 9;
// 大写字母ascii码表从65开始
private static final int capitalIndex = 65;
// 小写字母ascii码表从65开始
private static final int lowercaseIndex = 97;
// 特殊字符的起始ascii码表序号取第一个数字
private static final int special = 0;
// 特殊字符集，第一个数字代表ascii码表序号，第二个代表从这里开始一共使用多少个字符
private static final int[][] specialCharacter = {{33, 14}, {58, 6}, {91, 5}, {123, 3}};
// 取随机密码
public String getRandomPassword() throws Exception {
StringBuffer buffer = new StringBuffer();
if (length <= 0)
throw new Exception("length can not <= 0");
for (int i = 0; i < length; i++)
buffer.append((char) getNextChar());
return buffer.toString();
}
// 取得下一个ascii编码
private int getNextChar() throws Exception {
if (strengthLevel < 1 || strengthLevel > 4)
throw new Exception("This level is not supported");
// ascii编码
int x = 0;
// 伪字符ascii编码
final int puppetLetter = RANDOM.nextInt(randomMax) % numberOfLetter;
// 伪数字ascii编码
final int puppetNumber = RANDOM.nextInt(randomMax) % numberMax + nunberIndex;
// 按照字符等级强度取ascii值
final int levelIndex = RANDOM.nextInt(randomMax) % strengthLevel;
// 特殊字符的随机集合下标（数组第一维）
final int specialType = RANDOM.nextInt(randomMax) % specialCharacter.length;
// 特殊字符的ascii编码
final int specialInt = RANDOM.nextInt(randomMax) % specialCharacter[specialType][index] + specialCharacter[specialType][special];
// 根据密码强度等级获取随机ascii编码
switch (strengthLevel) {
case 1:
x = puppetNumber;
break;
case 2:
if (levelIndex == index)
x = puppetNumber;
else
x = puppetLetter + lowercaseIndex;
break;
case 3:
if (levelIndex == 0)
x = puppetNumber;
else if (levelIndex == index)
x = puppetLetter + lowercaseIndex;
else
x = puppetLetter + capitalIndex;
break;
case 4:
if (levelIndex == 0)
x = puppetNumber;
else if (levelIndex == index)
x = puppetLetter + lowercaseIndex;
else if (levelIndex == index * 2)
x = puppetLetter + capitalIndex;
else
x = specialInt;
break;
default:
}
return x;
}
public static void main(String[] args) {
System.out.println(System.currentTimeMillis());
Password password = new Password();
for (int i = 0; i < 10000; i++)
try {
System.out.println(password.getRandomPassword());
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(System.currentTimeMillis());
}
}
文章来源: wretchant.blog.csdn.net，作者：简简单单OnlineZuozuo，版权归原作者所有，如需转载，请联系作者。
原文链接：wretchant.blog.csdn.net/article/details/78248575
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