Check if word contains substring in Java Regex

If I want to check all words that contain the substring DEF, would this be the right approach:

^.*[D][E][F].*$

Also is there an easy rule when negating regexes, i.e. modifying the above to identify strings that don't contain DEF

EDIT: I know this doesn't require regexes, but for my pu开发者_StackOverflowrposes it does.

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This works too:

^.*DEF.*$

It checks, if the whole String contains the substring "DEF" at least once. But for trivial expressions like this:

str.contains("DEF");

does the same.

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Why not just use str.contains("DEF") and !str.contains("DEF")?

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You can simply use DEF as your regexp. To identify strings that don't contain it, simply return the strings that don't match the above expression.