jackson assign default value of a property is missing

Question

Is there any way to assign default value when a property is missing in Json file while deserializing JSon using Jackson

@NoArgsConstructor
@Getter
@JsonIgnoreProperties(ignoreUnknown = true)
@JsonInclude(NON_NULL)
@AllArgsConstructor
public class Sample {

    private String value = "hai";

   /* public Sample(String value) {
       this.value = value; // when I remove @AllArgsConstructor and  uncomment this constructor ,the default value is assigned if the property is missing in Json file
    }*/ 
 }

Is Jackson a good library? – John Zabroski Apr 09 '19 at 13:20 — John Zabroski, Apr 09 '19 at 13:20

score 0 · Accepted Answer · answered Oct 31 '17 at 09:24

0

You need not do anything for this,

class Student {
  public String course = "MATH";
}

If course value is missing from the JSON, the value in the bean will by default set to MATH.

answered Oct 31 '17 at 09:24

Neeraj Jain

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NO , the value is actually returned as null – Priya Oct 31 '17 at 09:28
@Priya Post your JSON structure and the output. – Neeraj Jain Oct 31 '17 at 09:43
@Priya It can be null only in the case if the JSON is explicitly setting the value of this property to null, but that you didn't ask for. – Neeraj Jain Oct 31 '17 at 09:46
I have edited my Question – Priya Oct 31 '17 at 13:04
@Priya It can be due to jackson version it it's jackson 2.10 then, for missing properties jackson will replace with null, even if we set default value in `Student` calss – Pradip Sodha Mar 18 '21 at 10:24

jackson assign default value of a property is missing

1 Answers1