How to Deserialize a Generic List with Gson?

Deserializing a Generic List with Gson

When using Gson to transfer a list object, you may encounter challenges when dealing with generic types. This article provides a comprehensive guide to deserializing generic lists with Gson.

Problem:
Attempting to deserialize a list using new List().getClass() results in an error or a complex fix with numerous method stubs.

Solution:
To correctly deserialize a generic list, employ the TypeToken class as follows:

Type listType = new TypeToken<List<MyClass>>() {}.getType();
MyClass mc = new Gson().fromJson(result, listType);

This approach eliminates the need for the getClass() invocation, providing a more concise and effective solution.

Explanation:
TypeToken captures the generic type at compile time. The anonymous subclass created during instantiation ensures that the correct type information is maintained when passed to Gson's fromJson method. This ensures proper deserialization of your generic list.

Additional Notes:

• The Type object can represent any Java type, including parameterized instantiations of generic types, overcoming type erasure limitations.
• TypeToken must capture types fully known at compile time; it cannot capture generic type parameters (new TypeToken>() {}.getType() is not allowed).
• For进一步了解如何使用 TypeToken 类，请参阅其文档。

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