Different names of JSON property during serialization and deserialization

java

json-annotations

serialization

deserialization

byAnton Shumikhin·Sep 19, 2024

To specify different names for serialization and deserialization in a JSON property, Jackson's @JsonProperty and @JsonAlias annotations can be used:

@JsonProperty("serialized_name")
private String propertyName;  //name for serialization

@JsonAlias({"alias1", "alias2"})
public void setPropertyName(String propertyName) { //names for deserialization
    this.propertyName = propertyName;
}

Here, the property is serialized as "serialized_name" and can be deserialized as either "alias1" or "alias2".

A closer look at Jackson annotations

Choosing the right annotation

When you need to map a Java field to a JSON property, @JsonProperty is your best friend:

When used on a field, it provides the serialization name.
When used on getters and setters, it specifies both serialization and deserialization names.
To add multiple names for a JSON property during deserialization, use @JsonAlias.

Naming methods with annotations

For clearer code, use @JsonGetter and @JsonSetter for explicit method-level naming:

Make your method names consistent with the intended JSON property.
Use multiple getters and setters with @JsonProperty to manage different serialization scenarios.

Keeping in sync with Jackson versions

To use these features, make sure your Jackson library is up-to-date. For instance, @JsonAlias was introduced in Jackson 2.9.0.

Watch out for common roadblocks

Navigating the import jungle

When you're working with Lombok, heed to the differences between Lombok's @Getter and Jackson's @JsonGetter. They serve different purposes and you don't want them to bump heads.

Dealing with field naming quirks

Field names in your annotations must match the expected JSON format exactly. Any discrepancy can give you a big, bad, Unrecognized field exception.

Applied in real life scenarios

Dealing with legacy systems

Legacy systems or third-party APIs often have strange naming conventions. @JsonProperty and @JsonAlias provide the flexibility to normalize naming in your Java model.

Versioning your APIs

When you version your APIs, you might need to support older JSON property names. @JsonAlias makes this possible while promoting the use of new names.

Ensuring team alignment

Make sure your team theknows about these annotations and includes them in your project's guidelines. This ensures code consistency and avoids confusion.

Testing for data integrity

Thoroughly test your serialization and deserialization process to catch potential mapping errors early on. This keeps your production environment neat and tidy.

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