本文实例讲述了java实现的密码强度检测功能。分享给大家供大家参考，具体如下：
CheckStrength.java文件：
package com.wx.pwd;
/**
* 检测密码强度
*
* @author venshine
*/
public class CheckStrength {
public enum LEVEL {
EASY, MIDIUM, STRONG, VERY_STRONG, EXTREMELY_STRONG
}
/**
* NUM 数字
* SMALL_LETTER 小写字母
* CAPITAL_LETTER 大写字母
* OTHER_CHAR 特殊字符
*/
private static final int NUM = 1;
private static final int SMALL_LETTER = 2;
private static final int CAPITAL_LETTER = 3;
private static final int OTHER_CHAR = 4;
/**
* 简单的密码字典
*/
private final static String[] DICTIONARY = {"password", "abc123", "iloveyou", "adobe123", "123123", "sunshine",
"1314520", "a1b2c3", "123qwe", "aaa111", "qweasd", "admin", "passwd"};
/**
*检查字符类型，包括num、大写字母、小写字母和其他字符。
*
* @param c
* @return
*/
private static int checkCharacterType(char c) {
if (c >= 48 && c <= 57) {
return NUM;
}
if (c >= 65 && c <= 90) {
return CAPITAL_LETTER;
}
if (c >= 97 && c <= 122) {
return SMALL_LETTER;
}
return OTHER_CHAR;
}
/**
* 按不同类型计算密码的数量
*
* @param passwd
* @param type
* @return
*/
private static int countLetter(String passwd, int type) {
int count = 0;
if (null != passwd && passwd.length() > 0) {
for (char c : passwd.toCharArray()) {
if (checkCharacterType(c) == type) {
count++;
}
}
}
return count;
}
/**
* 检查密码的强度
*
* @param passwd
* @return strength level
*/
public static int checkPasswordStrength(String passwd) {
if (StringUtils.equalsNull(passwd)) {
throw new IllegalArgumentException("password is empty");
}
int len = passwd.length();
int level = 0;
// 增加点
//判断密码是否含有数字有level++
if (countLetter(passwd, NUM) > 0) {
level++;
}
//判断密码是否含有小写字母有level++
if (countLetter(passwd, SMALL_LETTER) > 0) {
level++;
}
//判断密码是否还有大写字母有level++
if (len > 4 && countLetter(passwd, CAPITAL_LETTER) > 0) {
level++;
}
//判断密码是否还有特殊字符有level++
if (len > 6 && countLetter(passwd, OTHER_CHAR) > 0) {
level++;
}
//密码长度大于4并且2种类型组合......（不一一概述）
if (len > 4 && countLetter(passwd, NUM) > 0 && countLetter(passwd, SMALL_LETTER) > 0
|| countLetter(passwd, NUM) > 0 && countLetter(passwd, CAPITAL_LETTER) > 0
|| countLetter(passwd, NUM) > 0 && countLetter(passwd, OTHER_CHAR) > 0
|| countLetter(passwd, SMALL_LETTER) > 0 && countLetter(passwd, CAPITAL_LETTER) > 0
|| countLetter(passwd, SMALL_LETTER) > 0 && countLetter(passwd, OTHER_CHAR) > 0
|| countLetter(passwd, CAPITAL_LETTER) > 0 && countLetter(passwd, OTHER_CHAR) > 0) {
level++;
}
//密码长度大于6并且3中类型组合......（不一一概述）
if (len > 6 && countLetter(passwd, NUM) > 0 && countLetter(passwd, SMALL_LETTER) > 0
&& countLetter(passwd, CAPITAL_LETTER) > 0 || countLetter(passwd, NUM) > 0
&& countLetter(passwd, SMALL_LETTER) > 0 && countLetter(passwd, OTHER_CHAR) > 0
|| countLetter(passwd, NUM) > 0 && countLetter(passwd, CAPITAL_LETTER) > 0
&& countLetter(passwd, OTHER_CHAR) > 0 || countLetter(passwd, SMALL_LETTER) > 0
&& countLetter(passwd, CAPITAL_LETTER) > 0 && countLetter(passwd, OTHER_CHAR) > 0) {
level++;
}
//密码长度大于8并且4种类型组合......（不一一概述）
if (len > 8 && countLetter(passwd, NUM) > 0 && countLetter(passwd, SMALL_LETTER) > 0
&& countLetter(passwd, CAPITAL_LETTER) > 0 && countLetter(passwd, OTHER_CHAR) > 0) {
level++;
}
//密码长度大于6并且2种类型组合每种类型长度大于等于3或者2......（不一一概述）
if (len > 6 && countLetter(passwd, NUM) >= 3 && countLetter(passwd, SMALL_LETTER) >= 3
|| countLetter(passwd, NUM) >= 3 && countLetter(passwd, CAPITAL_LETTER) >= 3
|| countLetter(passwd, NUM) >= 3 && countLetter(passwd, OTHER_CHAR) >= 2
|| countLetter(passwd, SMALL_LETTER) >= 3 && countLetter(passwd, CAPITAL_LETTER) >= 3
|| countLetter(passwd, SMALL_LETTER) >= 3 && countLetter(passwd, OTHER_CHAR) >= 2
|| countLetter(passwd, CAPITAL_LETTER) >= 3 && countLetter(passwd, OTHER_CHAR) >= 2) {
level++;
}
//密码长度大于8并且3种类型组合每种类型长度大于等于3或者2......（不一一概述）
if (len > 8 && countLetter(passwd, NUM) >= 2 && countLetter(passwd, SMALL_LETTER) >= 2
&& countLetter(passwd, CAPITAL_LETTER) >= 2 || countLetter(passwd, NUM) >= 2
&& countLetter(passwd, SMALL_LETTER) >= 2 && countLetter(passwd, OTHER_CHAR) >= 2
|| countLetter(passwd, NUM) >= 2 && countLetter(passwd, CAPITAL_LETTER) >= 2
&& countLetter(passwd, OTHER_CHAR) >= 2 || countLetter(passwd, SMALL_LETTER) >= 2
&& countLetter(passwd, CAPITAL_LETTER) >= 2 && countLetter(passwd, OTHER_CHAR) >= 2) {
level++;
}
//密码长度大于10并且4种类型组合每种类型长度大于等于2......（不一一概述）
if (len > 10 && countLetter(passwd, NUM) >= 2 && countLetter(passwd, SMALL_LETTER) >= 2
&& countLetter(passwd, CAPITAL_LETTER) >= 2 && countLetter(passwd, OTHER_CHAR) >= 2) {
level++;
}
//特殊字符>=3 level++;
if (countLetter(passwd, OTHER_CHAR) >= 3) {
level++;
}
//特殊字符>=6 level++;
if (countLetter(passwd, OTHER_CHAR) >= 6) {
level++;
}
//长度>12 >16 level++
if (len > 12) {
level++;
if (len >= 16) {
level++;
}
}
// 减少点
if ("abcdefghijklmnopqrstuvwxyz".indexOf(passwd) > 0 || "ABCDEFGHIJKLMNOPQRSTUVWXYZ".indexOf(passwd) > 0) {
level--;
}
if ("qwertyuiop".indexOf(passwd) > 0 || "asdfghjkl".indexOf(passwd) > 0 || "zxcvbnm".indexOf(passwd) > 0) {
level--;
}
if (StringUtils.isNumeric(passwd) && ("01234567890".indexOf(passwd) > 0 || "09876543210".indexOf(passwd) > 0)) {
level--;
}
if (countLetter(passwd, NUM) == len || countLetter(passwd, SMALL_LETTER) == len
|| countLetter(passwd, CAPITAL_LETTER) == len) {
level--;
}
if (len % 2 == 0) { // aaabbb
String part1 = passwd.substring(0, len / 2);
String part2 = passwd.substring(len / 2);
if (part1.equals(part2)) {
level--;
}
if (StringUtils.isCharEqual(part1) && StringUtils.isCharEqual(part2)) {
level--;
}
}
if (len % 3 == 0) { // ababab
String part1 = passwd.substring(0, len / 3);
String part2 = passwd.substring(len / 3, len / 3 * 2);
String part3 = passwd.substring(len / 3 * 2);
if (part1.equals(part2) && part2.equals(part3)) {
level--;
}
}
if (StringUtils.isNumeric(passwd) && len >= 6) { // 19881010 or 881010
int year = 0;
if (len == 8 || len == 6) {
year = Integer.parseInt(passwd.substring(0, len - 4));
}
int size = StringUtils.sizeOfInt(year);
int month = Integer.parseInt(passwd.substring(size, size + 2));
int day = Integer.parseInt(passwd.substring(size + 2, len));
if (year >= 1950 && year < 2050 && month >= 1 && month <= 12 && day >= 1 && day <= 31) {
level--;
}
}
if (null != DICTIONARY && DICTIONARY.length > 0) {// dictionary
for (int i = 0; i < DICTIONARY.length; i++) {
if (passwd.equals(DICTIONARY[i]) || DICTIONARY[i].indexOf(passwd) >= 0) {
level--;
break;
}
}
}
if (len <= 6) {
level--;
if (len <= 4) {
level--;
if (len <= 3) {
level = 0;
}
}
}
if (StringUtils.isCharEqual(passwd)) {
level = 0;
}
if (level < 0) {
level = 0;
}
return level;
}
/**
*获得密码强度等级，包括简单、复杂、强、强、强
*
* @param passwd
* @return
*/
public static LEVEL getPasswordLevel(String passwd) {
int level = checkPasswordStrength(passwd);
switch (level) {
case 0:
case 1:
case 2:
case 3:
return LEVEL.EASY;
case 4:
case 5:
case 6:
return LEVEL.MIDIUM;
case 7:
case 8:
case 9:
return LEVEL.STRONG;
case 10:
case 11:
case 12:
return LEVEL.VERY_STRONG;
default:
return LEVEL.EXTREMELY_STRONG;
}
}
}
StringUtils.java文件：
package com.wx.pwd;
/**
* 字符串工具类
*
* @author venshine
*/
public class StringUtils {
private final static int[] SIZE_TABLE = {9, 99, 999, 9999, 99999, 999999, 9999999, 99999999, 999999999,
Integer.MAX_VALUE};
/**
* 计算一个整数的大小
*
* @param x
* @return
*/
public static int sizeOfInt(int x) {
for (int i = 0; ; i++)
if (x <= SIZE_TABLE[i]) {
return i + 1;
}
}
/**
* 判断字符串的每个字符是否相等
*
* @param str
* @return
*/
public static boolean isCharEqual(String str) {
return str.replace(str.charAt(0), ' ').trim().length() == 0;
}
/**
* 确定字符串是否为数字
*
* @param str
* @return
*/
public static boolean isNumeric(String str) {
for (int i = str.length(); --i >= 0; ) {
if (!Character.isDigit(str.charAt(i))) {
return false;
}
}
return true;
}
/**
* 判断字符串是否为空格、空(“)”或null。
*
* @param str
* @return
*/
public static boolean equalsNull(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0 || str.equalsIgnoreCase("null")) {
return true;
}
for (int i = 0; i < strLen; i++) {
if ((Character.isWhitespace(str.charAt(i)) == false)) {
return false;
}
}
return true;
}
}
CheckPWD.java文件：
package com.wx.pwd;
public class CheckPWD {
public static void main(String[] args) {
String passwd = "myNameJOB123_-+=";
System.out.println(CheckStrength.checkPasswordStrength(passwd));
System.out.println(CheckStrength.getPasswordLevel(passwd));
}
}
运行结果：
13
EXTREMELY_STRONG
PS：这里再为大家提供两款功能类似的在线工具供大家参考：
密码安全性在线检测：
http://tools.jb51.net/password/my_password_safe
高强度密码生成器：
http://tools.jb51.net/password/CreateStrongPassword
在线随机数字/字符串生成工具：
http://tools.jb51.net/aideddesign/suijishu
更多关于java算法相关内容感兴趣的读者可查看本站专题：《Java数据结构与算法教程》、《Java字符与字符串操作技巧总结》、《Java操作DOM节点技巧总结》、《Java文件与目录操作技巧汇总》和《Java缓存操作技巧汇总》
希望本文所述对大家java程序设计有所帮助。