FasterXML Jackson Examples

This project demonstrates various FasterXML Jackson annotations in a Spring Boot application. It showcases common JSON serialization and deserialization scenarios using Jackson annotations.

Features

The project includes examples of the following Jackson annotations:

1. Basic JSON Serialization (/hello)

   • Simple example of JSON response using Spring RestController

2. @JsonIgnore (/json-ignore)

   • Demonstrates how to exclude fields from JSON serialization
   • Example shows a field marked with @JsonIgnore being excluded from the response

3. @JsonProperty (/json-property)

   • Shows how to customize field names in JSON output
   • Converts camelCase Java field names to snake_case JSON properties

4. @JsonInclude (/json-include)

   • Demonstrates how to control which fields are included in JSON output
   • Example shows excluding null fields from the response

5. @JsonFormat (/json-format)

   • Shows how to format fields like dates during serialization
   • Example demonstrates formatting dates with specific patterns and timezones

6. @JsonUnwrapped (/json-unwrapped)

   • Demonstrates how to flatten nested objects during serialization
   • Example shows unwrapping an Address object into the main JSON structure

7. @JsonAnyGetter and @JsonAnySetter (/json-any-getter-setter)

   • Shows how to handle arbitrary key-value pairs during serialization and deserialization
   • Example demonstrates serializing a map into top-level properties and deserializing unknown properties into a map

8. @JsonTypeInfo and @JsonSubTypes (/json-type)

   • Demonstrates handling polymorphic types during serialization and deserialization
   • Example shows serializing and deserializing different Device subtypes (Laptop, Desktop) based on a type field

9. @JsonSerialize (/json-serialize)

   • Shows how to use a custom serializer for a specific type
   • Example demonstrates using a GreetingSerializer to customize the JSON output

Requirements

• Java 21
• Spring Boot 3.4.5

Running the Application

You can run the application using the Maven wrapper:

./mvnw spring-boot:run

Testing

To run the tests:

./mvnw test

Endpoints

1. GET /hello - Returns a simple JSON message
2. GET /json-ignore - Demonstrates @JsonIgnore annotation
3. GET /json-property - Shows @JsonProperty annotation usage
4. GET /json-include - Demonstrates @JsonInclude annotation
5. GET /json-format - Demonstrates @JsonFormat annotation
6. GET /json-unwrapped - Demonstrates @JsonUnwrapped annotation
7. POST /json-any-getter-setter - Demonstrates @JsonAnyGetter and @JsonAnySetter annotations
8. POST /json-type - Demonstrates @JsonTypeInfo and @JsonSubTypes annotations
9. POST /json-serialize - Demonstrates @JsonSerialize with a custom serializer

Technologies Used

• Spring Boot
• FasterXML Jackson
• JUnit 5
• MockMVC
• AssertJ