英文:
Password validation using Java regex fails
问题
我的要求包括验证密码输入，确保以下特殊字符仅出现一次：!@#$%^&*()_+=?~
为了实现这一目标，我编写了以下代码：
StringBuilder builder = new StringBuilder("^(?!.*(.).*\)");
builder.append("(?=.*[a-z])");
builder.append("(?=.*[!@#$%^&*()_+=?~])");
Pattern pattern = Pattern.compile(builder.toString());
Matcher matcher = pattern.matcher(input);
if (matcher.matches()) {
return true;
}
但是，当我在单元测试中传入有效输入时，这段代码总是失败。我对正则表达式不太了解。
英文:
My requirements include among other things to validate for the password input to include one of the following characters only once. !@#$%^&*()_+=?~
To accomplish that I wrote the following:
StringBuilder builder = new StringBuilder("(?=.*[a-z])");
builder.append("(?=.{1}[!@#$%^&*()_+=?~])");
Pattern pattern = Pattern.compile(builder.toString());
Matcher matcher = pattern.matcher(input);
if(matcher.matches){
return True;
}
But this always fails when I pass valid input in my unit test. I am new to regex.
答案1
得分: 0
你可以使用带有两个正向先行断言的这个正则表达式：
^(?=[^a-z]*[a-z])(?=[^!@#$%^&*()_+=?~]*[!@#$%^&*()_+=?~][^!@#$%^&*()_+=?~]*$).{12,}$
注意，在.matches()方法中，开始和结束锚点在给定的正则表达式中会自动隐含。
正则表达式详情：
^：开始(?=[^a-z]*[a-z])：正向先行断言，确保至少有一个小写字母(?=[^!@#$%^&*()_+=?~]*[!@#$%^&*()_+=?~][^!@#$%^&*()_+=?~]*$)：正向先行断言，确保仅有一个给定的特殊字符。.{12,}：匹配至少12个任意字符$：结束
英文:
You may use this regex with 2 lookahead assertions:
^(?=[^a-z]*[a-z])(?=[^!@#$%^&*()_+=?~]*[!@#$%^&*()_+=?~][^!@#$%^&*()_+=?~]*$).{12,}$
Note that in .matches() method start & end anchors are automatically implied in a given regex.
RegEx Details:
^: Start(?=[^a-z]*[a-z]): Positive lookahead to make sure we have at least one lowercase letter(?=[^!@#$%^&*()_+=?~]*[!@#$%^&*()_+=?~][^!@#$%^&*()_+=?~]*$): Positive lookahead to make sure we have ONLY one of the given special character..{12,}: Match min 12 of any characters$: End
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