如何将缺少的json字段反序列化为null？

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.databind.ObjectMapper;

public class MyClass {
    private String field1;
    private Integer field2;
    
    // getters and setters
    
    public static void main(String[] args) throws Exception {
        String json = "{\"field1\": \"value1\"}";
        
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
        
        MyClass obj = objectMapper.readValue(json, MyClass.class);
        
        System.out.println(obj.getField1());  // Output: value1
        System.out.println(obj.getField2());  // Output: null
    }
}

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;

import java.io.IOException;

public class MyClass {
    private String field1;
    private Integer field2;
    
    // getters and setters
    
    public static void main(String[] args) throws Exception {
        String json = "{\"field1\": \"value1\"}";
        
        ObjectMapper objectMapper = new ObjectMapper();
        SimpleModule module = new SimpleModule();
        module.addDeserializer(Integer.class, new CustomIntegerDeserializer());
        objectMapper.registerModule(module);
        
        MyClass obj = objectMapper.readValue(json, MyClass.class);
        
        System.out.println(obj.getField1());  // Output: value1
        System.out.println(obj.getField2());  // Output: null
    }
    
    static class CustomIntegerDeserializer extends JsonDeserializer<Integer> {
        @Override
        public Integer deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
            try {
                return jsonParser.getIntValue();
            } catch (Exception e) {
                return null;
            }
        }
    }
}