用GSon生成器和JSon文件填充Java类

Question

我想用一个外部JSon文件填充一个Java类，并使用Gson Builder。但是我的Java类将不会由我在JSon文件中声明的值填充。有什么问题？谢谢你的帮助

这是我的Json文件：

{
"tstamp": "2012-11-21 18:00",
"id": 123,
"publicationList": [
    {
        "id": "1L",
        "state": "PublicationState.IMMEDIATELY",
        "channel": "PublicationChannel.TIMETABLE", 
        "startDate": "2001-12-17 18:00",
        "endDate": "2001-12-17 18:00"
    },
    {
        "id": "2L",
        "state": "PublicationState.IMMEDIATELY",
        "channel": "PublicationChannel.NVS", 
        "startDate": "2001-12-17 18:00",
        "endDate": "2001-12-17 18:00"
    },
    {
        "id": "3L",
        "state": "PublicationState.IMMEDIATELY",
        "channel": "PublicationChannel.NVS", 
        "startDate": "2001-12-17 18:00",
        "endDate": "2001-12-17 18:00"
    }
]
}

这是我的Gson生成器和Gson实例创建者：

 Gson gson = new GsonBuilder()
            .setDateFormat("yyyy-MM-dd HH:mm")
            .registerTypeAdapter(Publication.class,
                    new PublicationInstanceCreator()).create();

 public class PublicationInstanceCreator implements
    InstanceCreator<PublicationDto> {

     @Override
     public PublicationDto createInstance(Type type) {

         return new PublicationDto();

     }

 }

这是Java类PublicAttionTo：

public class PublicationDto{

    private static final long serialVersionUID = 1L;

    private Long id;

    private PublicationState state = PublicationState.IMMEDIATELY;

    private PublicationChannel channel;

    private Date startDate;

    private Date endDate;


    //getter and setter methods

}

Answer 1

你的错误是什么？代码中也缺少主POJO对象

假设这个对象是Publications，您只需要使用

Publications p = new GsonBuilder().setDateFormat("yyyy-MM-dd HH:mm").create().fromJson(json, Publications.class);

你的适配器坏了。此外，我认为带有“L”的ID也不会起作用（去掉L），GSon会将数字转换为正确的长类型