CODEWITHSUNDEEP
java
kurumkan
kurumkan

Reputation: 2725

Json, regex, java. How to replace only one occurency of the substring

Suppose we have string like this

 {"className":"first","i":0,"name":null}

How to convert it into:

 {"className":"second","i":0,"name":null}

I have this one:

///Initialy className is a className in lower Case (for example "first")
 className = "\"className\":\""+className+"\",";

 string.replaceAll( "\"className\":\".+\"" ,className);

But it gives:

  {"className":"second",:null}

Upvotes: 0

Views: 1263

Answers (2)

Jeet
Jeet

Reputation: 248

Replace below statement string.replaceAll( "\"className\":\".+\"" ,className);

with string.replaceAll( "\"className\":\".+\""+"," ,className);

It gives.

{"className":"second","i":0,"name":null}

Upvotes: 1

ajb
ajb

Reputation: 31699

Your regex has ".+" in it. + is a "greedy" quantifier, which means that .+ will match the largest possible number of characters. So the matcher will look all the way to the furthest quote mark it can. If, instead, you want to match the smallest possible number of characters, add ? after the quantifier, i.e.

string.replaceAll( "\"className\":\".+?\"" ,className);

In Java this is called a "reluctant" qualifier. (I've seen it called other names as well.)

I agree with the comments that a regex is not the best approach for this problem.

Upvotes: 2

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