Gson到Pojo内部类的序列化

Question

I am trying to take a json and convert it into a POJO using Gson's ability. I got it working with the serialized class as a class in a separate package, but now I am trying to get the serialized class to be an inner class of the class which is calling it, kind of like how I have depicted below.

public class A {
    private final Gson gson;

    public A() {
        gson = new GsonBuilder().serializeNulls().create();
    }

    public void foo(String json){
        B b = gson.fromJson(json, B.class);
    }

    public static class B {
         private String bar;

         public String getBar(){
             return bar;
         }
    }
}

Sample JSON:

{"bar": "test"}

This setup returns null values for the inner class variables; in this case, just bar. I've made sure the json being passed in matches the names of variables in Class B, in this example. Additionally, I have experimented around with making the inner class non-static and private with no success. To my understanding it needs to be a static class in order for it to be serialized using gson. Is there anything blatantly obvious that I am doing wrong that you can see?

Answer 1

The error is somewhere else. Most probably the String or the Gson you pass is configured the wrong way. I pasted the exact same code and it works fine for me:

public class Main {

    public static void main (String[] args) {
        new A().foo("{\"bar\": \"test\"}");
    }

    public static class A {
        private final Gson gson;

        public A() {
            gson = new GsonBuilder().serializeNulls().create();
        }

        public void foo(String json){
            B b = gson.fromJson(json, B.class);
            System.out.println(b);
        }

        public static class B {
            private String bar;

            public String getBar(){
                return bar;
            }

            @Override
            public String toString() {
                return "B{bar='" + bar + '\'' +
                        '}';
            }
        }
    }

}

Inner classes are supposed to work so the problem is elsewhere. This will print out:

B{bar='test'}

Answer 2

So I imagine this is a common issue, now that I've run into it twice. The issue was in the JSON string being passed in. I copied and pasted the JSON from somewhere into the command line. As a result, the quotations weren't being registered as valid quotation marks. It was “ as opposed to " . The second is what is registered as a quotation mark. Thanks for all the help.