Convert Strings to Character Escapes and Unicode without StringEscapeUtils

Question

I'm doing some regex to split some Strings and extract both Unicode and normal escapes out of them (basically any escape accepted by Java), and then I want to parse them through a method.

This all works fine, however now I am at the point where once these escapes have been received, I want to transform them into their actual escape. For example, \n is literally converted into a newline.

I know I can use Apache's StringEscapeUtils, but I don't agree with their license for multiple reasons, and would rather be able to do it myself anyway.

From my understanding, I can simply do something like this:

switch (character) {
case 'n': return '\n';
case 't': return '\t';
default:  return '\0';
}

But I want to be able to parse things like \0345346 and \u3456, which Java will accept as valid entries, without writing every, single possible combination. I can regex these things just fine, but I want to be able to parse them into their literal values.

Is there any way I can acheive this?

score 0 · Accepted Answer · answered Feb 19 '17 at 05:28

This can easily be done by abusing the Properties class, which will actually parse String data and format correctly for you.

private char escapeCharacter(String data) {
    Properties p = new Properties();
    try {
        p.load(new StringReader("key=" + data));
    } catch (IOException e) {
        e.printStackTrace();
        return '\0';
    }
    return p.getProperty("key").charAt(0);
}

This will take in an escape code as a String, load it into the properties, parse it, and return the corrected char.

The function supports Unicode escapes and conventional escapes, as the question requests.

Convert Strings to Character Escapes and Unicode without StringEscapeUtils

1 Answers1