How to select one object in JSON array string using Java Regex?

Question

I have this String (please note that I must use this as string, not converted to JSON).

String cats = "[{'_id':'abxyz','image':'http://127.0.0.1/abxyz.png','name':'Tabby Cat'},{'_id':'xyzr2','image':'http://127.0.0.1/abxr2.png','name':'Calico Cat'},{'_id':'ghjkl','image':'http://127.0.0.1/ghjkl.png','name':'Persian Cat'},{'_id':'ojr12','image':'http://127.0.0.1/ojr12.png','name':'Angora Cat'}]";

or for better readability: (there is no white space between object)

String cats =
"[{'_id':'abxyz','image':'http://127.0.0.1/abxyz.png','name':'Tabby Cat'},\
{'_id':'xyzr2','image':'http://127.0.0.1/abxr2.png','name':'Calico Cat'},\
{'_id':'ghjkl','image':'http://127.0.0.1/ghjkl.png','name':'Persian Cat'},\
{'_id':'ojr12','image':'http://127.0.0.1/ojr12.png','name':'Angora Cat'}]";

I want to extract the Calico Cat object using regex. I tried to use

String pattern = "{\'_id\':\'xyzr2\'.*}"

Unfortunately, the selection expands from Calico Cat to Angora Cat:

{'_id':'xyzr2','image':'http://127.0.0.1/abxr2.png','name':'Calico Cat'},\
{'_id':'ghjkl','image':'http://127.0.0.1/ghjkl.png','name':'Persian Cat'},\
{'_id':'ojr12','image':'http://127.0.0.1/ojr12.png','name':'Angora Cat'}

What kind of regex pattern I need to isolate only the Calico Cat? Expected result:

{'_id':'xyzr2','image':'http://127.0.0.1/abxr2.png','name':'Calico Cat'}

Answer 1

You need to make it non-greedy to get smallest possible match

String pattern = "{\'_id\':\'xyzr2\'.*?}"

Regex explanation here.

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or use following regex

String pattern = "{\'_id\':\'xyzr2\'[^}]*}"

Regex explanation here.

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FYI : Always it's better to use json parser instead of hard coded regex, since the data is in valid json. Refer : How to parse JSON in Java