Simple way to add double quote in a JSON String

Question

I am trying to write something that returns some search suggestion result.

Suppose I have an string like this :

"[Harry,[harry potter,harry and david]]"

The format is like [A_STRING,A_STRING_ARRAY_HERE].

But I wany the output format to be like

[ "Harry",["harry potter","harry and david"]]

so that I can put it into the HTTP Response Body.

Is there a simple way to do this, I don't want to add "" for a very single String from scratch .

Solution

Demo

String text = "[Harry,[harry potter,harry and david]]";
text = text.replaceAll("[^\\[\\],]+", "\"$0\"");

System.out.println(text);

Output: ["Harry",["harry potter","harry and david"]]

---

Explanation:
If I understand you correctly you want to surround series of all non-[-and-]-and-, characters with double quotes. In that case you can simply use replaceAll method with regex ([^\\[\\],]+) in which which

• [^\\[\\],] - represents one non character which is not [ or ] or , (comma)
• [^\\[\\],]+ - + means that element before it can appear one or more times, in this case it represents one or more characters which are not [ or ] or , (comma)

Now in replacement we can just surround match from group 0 (entire match) represented by $0 with double brackets "$0". BTW since " is metacharacter in String (it is used to start and end string) we need to escape it if we want to create its literal. To do so we need to place \ before it so at the end it String representing "$0" needs to be written as "\"$0\"".

For more clarification about group 0 which $0 uses (quote from https://docs.oracle.com/javase/tutorial/essential/regex/groups.html):

There is also a special group, group 0, which always represents the entire expression.