Regex in java for the string

I am very new programmer to Java regular expressions. I do not want to use java split with delimiters and try getting the individual tokens. I don't feel its a neat way. I have the following string

"Some String lang:c,cpp,java file:build.java"

I want to 开发者_运维问答break up this into three parts

1 part containing "Some String" 
2 part containing "c,cpp,java" 
3 String containing "build.java"

The lang: and file: can be placed any where and they are optional.

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The lang: and file: can be placed any where and they are optional.

Try the following expressions to get the language list and the file:

String input = "Some String lang:c,cpp,java file:build.java";
String langExpression = "lang:([\\w,]*)";
String fileExpression = "file:([\w\.]*)";

Patter langPattern = Pattern.compile(langExpression);
Matcher langMatcher = langPattern.matcher(input);
if (langMatcher.matches()) {
  String languageList = langMatcher.group(1);
}

Patter filePattern = Pattern.compile(fileExpression );
Matcher fileMatcher = filePattern.matcher(input);
if (fileMatcher .matches()) { 
  String filename= fileMatcher.group(1);
}

This should work with lang:xxx file:xxx as well as file:xxx lang:xxx as long as the language list or the filename don't contain whitespaces. This would also work if lang: and/or file: was missing.

Would you also expect a string like this: file:build.java Some String lang:c,cpp,java?

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What is so "unmaintainable" about using split?

        String str = "Some String lang:c,cpp,java file:build.java";
        String[] s  = str.split("(lang|file):");

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While split can do what you want to achieve, you can write your own code using substring and indexOf methods. This will be far faster than using split in terms of performance.