How to validate a JSON object in java? -

i use sf.json library map form data incoming request in web application in java.

lets incoming request http://localhost:8080/app/addprofile form data as:

formdata: {      "name":"applicant name",    "age":"26",    "academics":{         "college":"80",       "inter":"67",       "matriculation":"89"    },    "skill":{         "computer":"c,c++,java",       "maths":"limit,permutation,statistics"    },    "dateofbirth":"09-07-1988" } 

server side :

string requestformdata=request.getparameter("formdata"); jsonobject formdata = jsonobject.fromobject(requestformdata); string name= formdata.getstring("name");  if(name.length>70){ //error message length validation }  if(!name.matches("regex name"){ //error message name validation } ... ... ... 

the main problem approach if there minor modification in json structure, entire code needs modified.

is there api can configure rules required validation?

you can use json validator: - https://github.com/fge/json-schema-validator

or can try parse json using google gson , catch syntax exception validate below :-

try{ jsonparser parser = new jsonparser(); parser.parse(passed_json_string); }  catch(jsonsyntaxexception jse){ system.out.println("not valid json string:"+jse.getmessage()); } 

for generic data validation, define rules in json schema , validate incoming json against schema.
in schema can define type of values can contain, range etc.
schema generation, can use online tool :- http://jsonschema.net/#/

you can refer post, have quick understanding of json schema:- http://json-schema.org/example1.html

example:-

"price": {             "type": "number",             "minimum": 0,             "exclusiveminimum": true         } 

above code defines price in json schema, when json object validated against schema, ensure price shouldn't zero, should more 0 , should number. if string or 0 or negative value passed in price, validation fail.