我可以在运行时创建JSON到Java POJO吗？

Question

I have a requirement where I am getting the JSON response from REST API.

I can create a POJO and convert the JSON to JAVA but this particulat POJO is of no use for me in future or in other functionality.

Hence I was thinking to convert the JSON to Java dynamically using any API and render the objects in the JSP.

Can you tell me is this a good practise and how can I do that?

Expected JSON Response:

{
"_id": "",
"title": "",
"contact": "",
"country": "",
"children": [
   {
     "title": "",
      "contact": "",
      "country": "",
      "children": [
          {
            "title": "",
            "contact": "",
            "country": "",
            "children": []
           }
          ]
        }
      ]
     }

Answer 1

I don't think it is a good practice since doing the conversion to an actual Java POJO you are verifying the JSON is correct in some way according to what you expect to receive, not a real verification but better than nothing.

In any case, if you don't want to have an actual Java POJO you can use a Map<String,Object> to store the data and render it in the jsp, you can use Jackson library to accomplish that conversion.

Regards.

UPDATE FOR QUESTION:

It looks quite simple with that schema, you can use the same class as parent and children, something like this:

public class YourPojo implements Serializable {
    private String _id; // not good practice start by underscore
    private String title;
    private String contact;
    private String country;
    private List<YourPojo> children;

    // constructors, getters, setters...
}

Regards.

Answer 2

I would use an approach similar to what you have in XML: parse the JSON into a generic structure (DOM for XML) and then use configurable means to extract the data you are interested in eg XPath for XML or JSONPath for JSON.

This means you end up with code that can handle any well-formed JSON and that can be used to extract any part of the message through configuration.