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Learn how to effectively handle different variable names when mapping JSON data between APIs in Java using the `JsonProperty` annotation.
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Resolving JSON Property Naming Conflicts: JsonProperty Annotation in Java

In today’s interconnected software ecosystem, APIs often communicate with one another, requiring data transformations as they interact. One common challenge developers face is the discrepancy in JSON property naming conventions across different sources and destinations. This guide addresses the issue you may encounter when the source and destination APIs require different variable names for the same data.

The Problem: Name Mismatch Between APIs

Imagine you have three critical components in your application landscape:

Source A: Outputs a JSON format that includes fields named id and created_on.

Wrapper API B: Consumes the JSON from Source A and maps it to a Plain Old Java Object (POJO) that mirrors the incoming JSON structure.

Destination C: Requires the field to be in camel case, specifically createdOn, which leads to a mismatch, causing data retrieval issues.

Example JSON from Source A

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POJO for Wrapper API B

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When Wrapper API B is invoked, it correctly retrieves the data from Source A. However, when the data is sent to Destination C, it returns an incomplete response because Destination C expects the property createdOn instead of created_on. This is where the issue arises: the mapping is not transferring correctly between APIs.

The Solution: Utilizing @JsonProperty Annotation

To solve this mapping issue, you can leverage the @JsonProperty annotation from the Jackson library in your POJO for Destination C. This annotation allows you to specify how JSON properties correlate with Java fields, thereby addressing naming disparities directly.

Step-by-Step Implementation

Modify the POJO in Destination C: Add the @JsonProperty annotation to the createdOn field indicating that it should correspond to created_on from the incoming JSON structure. Here’s how your modified class will look:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Changes

@JsonProperty("created_on"): This annotation indicates to the Jackson library that when a JSON object is deserialized to this class, it should take the value of created_on from the JSON and assign it to the createdOn Java field. This effectively bridges the naming convention gap between JSON properties and your Java representation.

Testing the Update

After implementing the changes, redeploy your application and test the call from Destination C to Wrapper API B. You should now see a complete response containing both the id and createdOn fields as expected:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

In summary, navigating JSON property naming mismatches across diverse APIs can be streamlined using the @JsonProperty annotation from Jackson. By explicitly stating the relationship between JSON keys and Java object fields, you ensure effective data retrieval and transformation in your application. Now, the integration between Source A, Wrapper API B, and Destination C is seamless, providing the expected functionality.

Feel free to share your experiences with similar API integrations in the comments below. Happy coding!