Jackson

Sometimes we need to convert from Java Properties to a Java Object or vise versa. JavaPropsMapper from Jackson library class provides an easy way to do the conversion.

You can use ObjectMapper.convertValue to convert a java object to a java map.

The convertValue method in the ObjectMapper class allows you to convert a Java object of one type to another type, without the need for explicit serialization and deserialization steps.

This method takes two parameters: the source object and the target type (specified as a JavaType or TypeReference).

Let’s consider a simple example to demonstrate the usage of convertValue. Suppose we have a Person class, and we want to convert an instance of Person to a Map<String, Object> representation:

In this article, we’ll delve into the usage of SimpleBeanPropertyFilter in Jackson, a feature that allows you to filter and control the properties included in the JSON output during serialization. This filter provides fine-grained control over which properties are included, making it useful for customizing your JSON output.

The @JsonInclude annotation is used to specify whether fields with null values should be included in the JSON output. By applying this annotation to fields or at the class level, we can control how Jackson handles null fields during serialization.

Jackson provides a @JsonPropertyOrder annotation to specify the order of fields(possibly partial) on serialization. Fields included in annotation declaration will be serialized first in defined order, followed by any fields not included in the definition. This is very helpful when you want to ensure that some fields are output before other fields

The @JsonValue annotation is used to indicate that a method in a class should be used for serialization. When you apply this annotation to a method, Jackson will invoke that method to determine how the object should be represented in the JSON output.

@JacksonInject annotation is particularly valuable when you need to supply contextual data or configuration settings that are not present in the JSON being deserialized.

In this article, we’ll delve into the versatility of Jackson’s @JsonProperty annotation, which allows you to customize field names during both serialization and deserialization.

In this article, we’ll dive into an advanced Jackson annotation, @JsonIgnoreType, which allows you to exclude an entire class from being serialized when it’s used as a field within another class. Additionally, we’ll explore other techniques to prevent class serialization in Java.