Json字符串解析为具有多个对象的java对象

Question

正在尝试使用gson将以下json字符串解析为java对象

{
    "entry": "132456",
    "product": {
        "item": "123456",
        "prompts": [
            {
                "promptId": "1",
                "promptNumber": "109",
                "promptType": 4,
                "promptTypeDesc": "desc1",
                "validations": [
                    {
                        "minLen": 10,
                        "maxLen": 10,
                        "required": true
                    } 
                ] 
            },
            {
                "promptId": "2",
                "promptNumber": "110",
                "promptType": 4,
                "promptTypeDesc": "desc2",
                "validations": [
                    {
                        "minLen": 12,
                        "maxLen": 12,
                        "required": true
                    } 
                ] 
            },
            {
                "promptId": "3",
                "promptNumber": "72",
                "promptType": 5,
                "promptTypeDesc": "desc4",
                "validations": [
                    {
                        "required": true 
                    } 
                ] 
            } 
        ]
    }
}

我有自己的java类

 public class Info{
        private String entry;
        private Product product;
       // added setters and getters

  /* Product is inner class*/
  public static Product {
      private String item;
      private List<Prompt> prompts;
     // added getters and setters

     /*Prompt inner class*/
     public static Prompt{
        private String promptId;
        private String promptNumber;
        private List<Validation> validations;
        // getters and setters


      /*Validation inner class*/
      public static Validation{
          private int maxLen;
          private int minLen;
          private boolean required;
          // added getters and setters
      } // end of Validation class
    } // end of Prompt class
   } // end of Product
} // End of Info

转换后，我将提示对象设置为null

       item = gson.fromJson(response, Info.class);

有人能纠正我吗