Java PropertyBasedCreator-class And Method Code Example


Here is an example of how to use the PropertyBasedCreator class from the com.fasterxml.jackson.databind package in the Jackson library for Java:

import java.util.HashMap;
import java.util.Map;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.deser.std.StdValueInstantiator;
import com.fasterxml.jackson.databind.deser.std.StdValueInstantiator.PropertyBasedCreator;

public class Example {
    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        String json = "{\"id\":1,\"name\":\"Example\",\"data\":{\"key1\":\"value1\",\"key2\":\"value2\"}}";
        MyObject object = mapper.readValue(json, MyObject.class);
        System.out.println(object.toString());
    }

    static class MyObject {
        private final int id;
        private final String name;
        private final Map<String, String> data;

        @JsonCreator
        public MyObject(@JsonProperty("id") int id,
                        @JsonProperty("name") String name,
                        @JsonProperty("data") Map<String, String> data) {
            this.id = id;
            this.name = name;
            this.data = data;
        }

        public int getId() {
            return id;
        }

        public String getName() {
            return name;
        }

        public Map<String, String> getData() {
            return data;
        }

        @Override
        public String toString() {
            return "MyObject{" +
                    "id=" + id +
                    ", name='" + name + ''' +
                    ", data=" + data +
                    '}';
        }
    }
}

This code creates an instance of the ObjectMapper class, deserialize a json string to MyObject class, which has a property of Map<String, String> data and use JsonCreator and JsonProperty annotation to set the constructors and properties. Finally it prints the resulting object to the console.

The output of this code would be:

MyObject{id=1, name='Example', data={key1=value1, key2=value2}}

You can also create a PropertyBasedCreator instance by yourself and pass it to StdValueInstantiator class.

PropertyBasedCreator creator = new PropertyBasedCreator(new StdValueInstantiator(MyObject.class));
creator.addPropertyCreator(...);

Please note that, in this example, the JsonCreator and JsonProperty annotations are used to configure the constructors and properties. They are necessary to use PropertyBasedCreator class.