Question

Basically I need to retrieve data inside <> or {} blocks in a string in java.

The String may or may not contain a <> or {} tag.

The string might contain multiple <> or {} blocks.

Data inside the <> and {} blocks are basically variables or function names.

    d1 = "1234";
    d2 = "5678";
    sampleString = "aaa<d1>aaa{d1}aaa<d2>aaa";

I need the result to be similar to something like this.

    resultString = "aaa1234aaa4321aaa5678aaa";

thanks in advance. 🙂

EDIT

I should make note that the values inside the <> and {} blocks are dynamic.

I could have

    sampleString = "aaa<d5>aaa{d1}aaa<d2>aaa";

meaning it would get the value d5 from a property/variable/parameter/etc.

I should have stated that from the start. :p

Answer 1

First, create a Map for your values:

Map<String, String> values = new HashMap<String, String>();
values.put("d1", "1234");
values.put("d2", "5678");

Then, find all matches and replace them:

Matcher matcher = Pattern.compile("<(.*?)>").matcher(text);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
    matcher.appendReplacement(sb, values.get(matcher.group(1)));
}
matcher.appendTail(sb);

And again for the other pattern:

matcher = Pattern.compile("\\{(.*?)\\}").matcher(sb.toString());
sb = new StringBuffer();
while (matcher.find()) {
      matcher.appendReplacement(sb, new StringBuffer(values.get(matcher.group(1))).reverse().toString());
}
matcher.appendTail(sb);