java - 当Object-Key是随机的时，如何用Jackson2解析JSON？

Question

我想用 Jackson2 解析 Java 中的 JSON，其结构如下:

{
 "attachment": {
  "_2K26Z-mLJmMSRnssLwD0zQ": {
    "ext": "jpg",
    "height": 3024,
    "md5": "219c226e0070b7367f90e2f1bff1dfc2",
    "name": "IMG_1871.jpg",
    "ref": "MTUyMTAzNDY5MDUzNElNR18xODcxLmpwZw==",
    "rotate": true,
    "size": 1514957,
    "thumb": "thumb_1024_219c226e0070b7367f90e2f1bff1dfc2",
    "thumb_size": 73119,
    "type": "image",
    "width": 4032
    },
    "_Q7l14s87UquHcAYoolNCuw": {
      "ext": "png",
      "height": 186,
      "md5": "75023fd60d59907376943bf109858336",
      "name": "ns_attach_image_26071520280535225.png",
      "ref": "MTUyMDI4MDUzNTIzMG5zX2F0dGFjaF9pbWFnZV8yNjA3MTUyMDI4MDUzNTIyNS5wbmc=",
      "rotate": true,
      "size": 15182,
      "type": "image",
      "width": 347
    }
  },
  "title": "Test Title"
}

我的问题是我不知道如何处理附件的键，因为我无法定义具有未知名称字段的类。

有效的是

ObjectMapper mapper = new ObjectMapper();
Note note = mapper.readValue(fileio, Note.class); 

类注释在哪里

public class Note {
   private String title;
   private Object attachment;

   public String getTitle() {
      return title;
   }

   public void setTitle(String title) {
      this.title = title;
   }

   public Object getAttachment() {
      return attachment;
   }

   public void setAttachment(Object attachment) {
      this.attachment = attachment;
   }
}

但我想使用一个带有名称附件的类，该类包含 json 中键为“_2K26Z-mLJmMSRnssLwD0zQ”的所有字段。

Answer 1

您可以使用Map，这样附件的键就是映射中的键，映射中的值就是表示附件字段的对象。像这样:

public class Attachment {
    private String ext;
    private int height;
    private String md5;
    private String name;
    private String ref;
    private boolean rotate;
    private int size;
    private String thumb;
    private int thumb_size;
    private String type;
    private int width;

}

public class Note {
    private String title;

    private Map<String, Attachment> attachment = new HashMap<>();
}