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Deserializing JSON to Java Classes Dynamically using ObjectMapper

Learn how to dynamically deserialize JSON to Java classes using `ObjectMapper` and interface-based design for method calls. --- This video is based on the question https://stackoverflow.com/q/75282802/ asked by the user 'voila' ( https://stackoverflow.com/u/1936343/ ) and on the answer https://stackoverflow.com/a/75284439/ provided by the user 'Chaosfire' ( https://stackoverflow.com/u/17795888/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Jackson deserialize dynamically by class fully Qualified Name Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- How to Dynamically Deserialize JSON into Java Classes Using ObjectMapper In modern software development, especially when creating frameworks, it's not uncommon to need to deserialize JSON data into Java objects dynamically. One common scenario arises when developers create their classes, or "Beans," and define them in a configuration file. The objective? To fetch JSON data from various URLs and convert it into the respective class types as specified in that configuration. This post will walk you through how to achieve this using Jackson's ObjectMapper. The Problem Statement Suppose your developers can create Beans like the ones shown below: [[See Video to Reveal this Text or Code Snippet]] These classes are specified in a file called orchestration.csv in the following format: [[See Video to Reveal this Text or Code Snippet]] The challenge is how to deserialize the JSON fetched from these URLs into the correct class type and subsequently call the save() method of that instance. Below is the pseudo code attempting this: [[See Video to Reveal this Text or Code Snippet]] The Solution To solve this issue, we can leverage Java interfaces to ensure that each of our Bean classes implements a common behavior. Here's a step-by-step guide to achieve this. Step 1: Create an Interface First, define an interface, MyInterface, that will declare the save() method: [[See Video to Reveal this Text or Code Snippet]] Step 2: Implement the Interface in Bean Classes Next, modify your Bean classes to implement the MyInterface: [[See Video to Reveal this Text or Code Snippet]] Step 3: Deserialize JSON Dynamically and Invoke save() Now, modify your pseudo code to deserialize the JSON and call the save() method: [[See Video to Reveal this Text or Code Snippet]] Key Considerations Error Handling: Always handle JsonProcessingException to manage invalid JSON strings. Class Type Safety: The use of instanceof ensures that the object can indeed invoke the save() method safely. Extensibility: By using an interface, you can easily add new Beans while maintaining a clean architecture. Conclusion Through the adoption of interface-based design, we can effectively handle dynamic deserialization of Java objects and invocation of methods like save(). This structured approach not only solves the immediate problem but also sets a solid foundation for future expansions in your framework. In conclusion, remember to keep your Java classes clean and your JSON handling robust. Happy coding!