java - 如何用Gson提取字段？

Question

我有这个 json 代码(它是整个 json 代码的一部分):

{
  "numFound": 41, 
  "edges": [
    {
      "endLemmas": "albero", 
      "context": "/ctx/all", 
      "end": "/c/it/albero/v", 
      "features": [
        "/c/it/alberatura /r/ConceptuallyRelatedTo -", 
        "/c/it/alberatura - /c/it/albero/v", 
        "- /r/ConceptuallyRelatedTo /c/it/albero/v"
      ], 
      "license": "/l/CC/By-SA", 
      "start": "/c/it/alberatura", 
      "startLemmas": "alberatura", 
      "text": [
        "albero", 
        "alberatura"
      ], 
      "uri": "/a/[/r/ConceptuallyRelatedTo/,/c/it/alberatura/,/c/it/albero/v/]", 
      "weight": 1.0, 
      "dataset": "/d/conceptnet/5/combined-sa", 
      "sources": [
        "/and/[/s/rule/wiktionary_monolingual_definitions/,/s/web/en.wiktionary.org/]"
      ], 
      "score": 7.81056, 
      "rel": "/r/ConceptuallyRelatedTo", 
      "timestamp": "2013-09-12T16:30:04.157Z", 
      "nodes": [
        "/r/ConceptuallyRelatedTo", 
        "/c/it/albero/v", 
        "/c/it/alberatura"
      ], 
      "id": "/e/021aa72c7605d9d2000f0774a0bf9042699fa6ee", 
      "surfaceText": "[[alberatura]] ConceptuallyRelatedTo [[albero]]"
    }, 

如何提取“特征”字段？我可以提取一些字段，例如“上下文”或“结束”，但对于“特征”我不能! :(

我的Java代码:

   public static void main(String[] args) throws IOException {

   URL url = new URL("http://conceptnet5.media.mit.edu/data/5.1/c/it/albero?get=context");
      HttpURLConnection conn = (HttpURLConnection) url.openConnection();
      conn.setRequestMethod("GET");
      conn.setRequestProperty("Accept", "application/json");
      BufferedReader br = new BufferedReader(new InputStreamReader((conn.getInputStream())));

      String inputLine;

      GsonCNItem gsonCNObj = new Gson().fromJson(br, GsonCNItem.class);

      for (int i = 0; i < 3; i++) {
        try{
          gsonCNObj.getCNThing(i);
        }catch (IndexOutOfBoundsException e) {}      
      }
    }

我的 GsonCNItem 类:

public class GsonCNItem {

  private String context;
  private String end;
  private List<GsonCNItem> edges;

  public List<GsonCNItem> getCNedges(){
    return edges;
  }

 public void getCNThing (int i){
    System.out.println(edges.get(i));
  }

  public String toString(){
    return String.format("Context: %s\nend: %s",context,end);    
  }
}

感谢您的帮助!

Answer 1

但是你的反序列化 JSON 的类是错误的，它应该如下所示:

public class MyJson {
    private long numFound;
    private ArrayList<GsonCNItem> edges;

    public ArrayList<GsonCNItem> getEdges(){
        return getEdges();
    }

    public class GsonCNItem{
        private String endLemmas;
        private String context;
        private String end;
        private ArrayList<String> features;
        ...
        private ArrayList<String> text;
        ...

        public ArrayList<String> getFeatures(){
            return features;
        }

        public ArrayList<String> getText(){
            return text;
        }

        public String toString(){
            return String.format("Context: %s\nend: %s",context,end);
        }
    }
}