Question 109146 in Json Question posted in
Our archive of expertly curated questions and answers provides insights and solutions to common problems related to this popular data interchange format. From parsing and manipulating JSON data to integrating it with various programming languages and web services, our archive has got you covered. Start exploring today and take your JSON skills to the next level

Json – Design : Refer different properties for a object at run time

I’m looking for some advice to come up with a design for a use case on which I’m working. As a REST request I receive a Json payload something like below

{ 
  "marketEvent" :{
        "category": "Finance"
        "version": 1.0       
   }
   "history" : {
     "type" : "FX"
     "value": 45.33  
     "role" : " Broker"  
   } 
}

For different categories (in this example Finance), I need to access different values from the JSON. In case of Finance, I need to access history.type, but in another category I might need to access another value.

I’m looking for a generic design in Java/Spring where I can configure different categories and what values I need to access and take action on that.

Tags:

2

Answers


  1. 0

    Jayway is perfect for this. Along with a map from the categories and paths to the data.

    Dependency

    <dependency>
    <groupId>com.jayway.jsonpath</groupId>
    <artifactId>json-path</artifactId>
    <version>2.4.0</version>
</dependency>

    Code

    import java.util.HashMap;
import java.util.Map;

import com.jayway.jsonpath.DocumentContext;
import com.jayway.jsonpath.JsonPath;

public class App5 {

    
    public static void main(String[] args) {
        String jsonDataSourceString = "{ rn" + 
                "  "marketEvent" :{rn" + 
                "        "category": "Finance", rn" + 
                "        "version": 1.0       rn" + 
                "   }, rn" + 
                "   "history" : {rn" + 
                "     "type" : "FX", rn" + 
                "     "value": 45.33,  rn" + 
                "     "role" : " Broker"  rn" + 
                "   } rn" + 
                "}";

        System.out.println(jsonDataSourceString);

        Map<String, String> categoryToJsonPath = new HashMap<>();
        categoryToJsonPath.put("Finance", "$.history.type");
        
        String pathToCategory = "$.marketEvent.category";
        
        DocumentContext jsonContext = JsonPath.parse(jsonDataSourceString);
        String categoryName = jsonContext.read(pathToCategory);
        
        System.out.println(categoryName);

        String pathToCategoryDependentField = categoryToJsonPath.get(categoryName);
        
        String categoryDependentFieldValue = jsonContext.read(pathToCategoryDependentField);

        System.out.println(categoryDependentFieldValue);
        

    }

}

    Output:

    { 
  "marketEvent" :{
        "category": "Finance", 
        "version": 1.0       
   }, 
   "history" : {
     "type" : "FX", 
     "value": 45.33,  
     "role" : " Broker"  
   } 
}
Finance
FX
    Login or Signup to reply.
  2. 0

    You many try library Josson. Function caseValue() can do the job.

    https://github.com/octomix/josson

    Josson josson = Josson.fromJsonString(
    "{" +
    "  "marketEvent" :{" +
    "        "category": "Finance"," +
    "        "version": 1.0" +
    "   }," +
    "   "history" : {" +
    "     "type" : "FX"," +
    "     "value": 45.33," +
    "     "role" : " Broker"" +
    "   }" +
    "}");
String categoryValue = josson.getString(
    "marketEvent.category.caseValue(" +
    "  'Finance', $.history.type," +
    "  'IT', $.history.type2)");
System.out.println(categoryValue);
// Output: FX
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search