对于包含列表的 Java 类，如何从 json 字符串中获取对象，使用 Immutables 生成？

Question

my use case included a similar class, using immutables ( https://immutables.github.io/ ) :

@Value.Immutable
@Gson.TypeAdapters
public abstract class SampleClass {
    public abstract String var1();
    public abstract String var2();
    public abstract Date date1();
}

I was converting it to Json string,using gson, and then getting the object again using :

SampleClass obj1 = new Gson().fromJson("generated_json_string",ImmutableSampleClass.class);

But now I had to change var1 to List of String, and now I am getting :

java.lang.RuntimeException: Failed to invoke com.google.common.collect.ImmutableList() with no args

What is the correct way to get the object from JSON string ?

Answer 1

Figured out what was wrong, hence answering the question. Immutables generated class GsonAdaptersSampleClass, which implements TypeAdapterFactory. Using this and with the help of this answer : https://stackoverflow.com/a/13624060/3192744

I could find the following correct way to deserialize JSON string:

GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapterFactory(new GsonAdaptersSampleClass());
Gson gson = gsonBuilder.create();
SampleClass obj1 = gson.fromJson("generated_json_string",ImmutableSampleClass.class);

Answer 2

You can try GSON library for converting JSON to your existing class object.

http://howtodoinjava.com/best-practices/google-gson-tutorial-convert-java-object-to-from-json/