Got a question regarding regex matching in Java. Given is a string with a defined length. Now I want to check with a matcher if every char contained in that String is different.

For example (only pass of length = 8):

String a = "abcdefgz" -> pass
String b = "aacdefgz" -> fail
String c = "abcdefghz" -> fail

So matching the length would simply be:

"^[a-zA-Z]{8}$"

But to get it working in combination with the condition that every contained char needs to be unique is quite tough.

CodePudding user response：

Well, this one matches strings containing duplicates. This is basically the reverse of what you are looking for.

.*(.) .*\1.*

If it's suitable, you can pick string that do not match this expression. Or maybe check regex negative match to improve it.