regex - How to search a string of key/value pairs in Java

Question

I have a String that's formatted like this:

"key1=value1;key2=value2;key3=value3"

for any number of key/value pairs.

I need to check that a certain key exists (let's say it's called "specialkey"). If it does, I want the value associated with it. If there are multiple "specialkey"s set, I only want the first one.

Right now, I'm looking for the index of "specialkey". I take a substring starting at that index, then look for the index of the first = character. Then I look for the index of the first ; character. The substring between those two indices gives me the value associated with "specialkey".

This is not an elegant solution, and it's really bothering me. What's an elegant way of finding the value that corresponds with "specialkey"?

Answer 1

I would parse the String into a map and then just check for the key:

String rawValues = "key1=value1;key2=value2;key3=value3";
Map<String,String> map = new HashMap<String,String>();
String[] entries = rawValues.split(";");
for (String entry : entries) {
  String[] keyValue = entry.split("=");
  map.put(keyValue[0],keyValue[1]);
}

if (map.containsKey("myKey")) {
   return map.get("myKey");
}