Java Reg-ex to validate file convention

How to check if the following is part of the file name using regular expressions

.en.
.fr.
.pt.
.de.
.ja.
.es开发者_运维技巧.
.it.
.cn.

I know one other way is to check the index of and return boolean.

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Just do a match of \.(en|fr|pt|de|ja|es|it|cn|)\.

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Just use the regex...

.*\.(?:en|fr|pt|de|ja|es|it|cn)\..*

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Try this expression: \.(?:en|fr|pt|de|ja|es|it|cn)\. or for String#matches(): .*\.(?:en|fr|pt|de|ja|es|it|cn)\..* (note that in string literals, you need to escape the \\: ".*\\.(?:en|fr|pt|de|ja|es|it|cn)\\..*")

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string.matches(".*\\.(en|fr|pt|de|ja|es|it|cn)\\..*");

or you can precompile the pattern with

Pattern p = Pattern.compile(".*\\.(en|fr|pt|de|ja|es|it|cn)\\..*");

and check with p.matches(string);