CODEWITHSUNDEEP
javaspring-bootjackson
NRJ
NRJ

Reputation: 1204

Form pojo to parse JSON

My json looks like this :

{
   "bid": "181.57",
   "ask": "181.58",
   "volume": {
       "item1": "543.21",
       "item2": "123.45",
       "timestamp": 1487903100000
   },
   "last": "181.58"
}

I'm trying to use spring restTemplate to read it into a pojo. My current pojo is this :- 

import com.fasterxml.jackson.annotation.JsonProperty;

public class DataModel {
  private String last;

  private Volume volume;

  private String ask;

  private String bid;

  // Getter and setters
}

class Volume
{
    private String timestamp;

    @JsonProperty
    private String item1;

    @JsonProperty
    private String item2;

    // Gettersand setters
}

The problem is that "item1" and "item2" int the json can change to "item5" and "item6" depending on which entity I am querying for. I get null values if my variables are named item1 and item2. How can I keep generic names for the variables item1 and item2 and still be able to read the values correctly in the generic variables? Is there any annotation that will help here?

Upvotes: 1

Views: 155

Answers (1)

themantimes8
themantimes8

Reputation: 71

I believe this is what you are looking for from a Baeldung tutorial:

3.3. @JsonAnySetter

@JsonAnySetter allows you the flexibility of using a Map as standard properties. On de-serialization, the properties from JSON will simply be added to the map.

Let’s see how this works – we’ll use @JsonAnySetter to deserialize the entity ExtendableBean:

public class ExtendableBean {
    public String name;
    private Map<String, String> properties;

    @JsonAnySetter
    public void add(String key, String value) {
        properties.put(key, value);
    }
}

This is the JSON we need to deserialize:

{
    "name":"My bean",
    "attr2":"val2",
    "attr1":"val1"
}

And here’s how this all ties in together:

@Test
public void whenDeserializingUsingJsonAnySetter_thenCorrect()
  throws IOException {
    String json
      = "{\"name\":\"My bean\",\"attr2\":\"val2\",\"attr1\":\"val1\"}";

    ExtendableBean bean = new ObjectMapper()
      .readerFor(ExtendableBean.class)
      .readValue(json);

    assertEquals("My bean", bean.name);
    assertEquals("val2", bean.getProperties().get("attr2"));
}

In your case, you would simply query the map for the String values you expect for whichever query you are making.

Upvotes: 2

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