How to match "any character" in Java Regular Expression?

Question

The following should be matched:

AAA123
ABCDEFGH123
XXXX123

can i do: ".*123"?

Answer 1

Use the pattern . to match any character once, .* to match any character zero or more times, .+ to match any character one or more times.

Answer 2

Yes, you can. That should work.

• . = any char
• \. = the actual dot character
• .? = .{0,1} = match any char zero or one times
• .* = .{0,} = match any char zero or more times
• .+ = .{1,} = match any char one or more times

Answer 3

No, * will match zero-or-more characters. You should use + that matches one-or-more instead.

this expression might work better for you: [A-Z]+123

//Huusom

Answer 4

There are lots of sophisticated regex testing and development tools, but if you just want a simple test harness in Java, here's one for you to play with:

    String[] tests = {
        "AAA123",
        "ABCDEFGH123",
        "XXXX123",
        "XYZ123ABC",
        "123123",
        "X123",
        "123",
    };
    for (String test : tests) {
        System.out.println(test + " " +test.matches(".+123"));
    }

Now you can easily add new testcases and try new patterns. Have fun exploring regex.

See also

• regular-expressions.info/Tutorial

Answer 5

Yes that will work, though note that . will not match newlines unless you pass the DOTALL flag when compiling the expression:

Pattern pattern = Pattern.compile(".*123", Pattern.DOTALL);
Matcher matcher = pattern.matcher(inputStr);
boolean matchFound = matcher.matches();