如何从JSON响应中获取所有属性名称（是否嵌套）

Question

I have following json response. I am not able to iterate through each Map . Please help me

{"status":"OK","result":{"1":{"Id":"3","Conferencce":"test3","Description":"test3","Admin":"919818559890","Moderator":null,"Keywords":"test3","StartDate":"2011-11-19 12:22:33","EndDate":"2011-11-19 14:22:33","Type":"both","MaxAtendee":"0","MinAtendee":"0","RegAtendee":"0","DescVoiceVideo":null,"Rating":null,"Status":"active","ApproveBy":null,"ApprovedOn":"2011-11-15 14:22:33","ApprovedReason":null,"AdminPin":null,"UserPin":null,"PricePerMin":null,"PricePerConf":null,"ReminderStart":null,"AdminJoin":null,"CreatedOn":"2011-11-17 13:31:27","CreatedBy":"1"},"2":{"Id":"2","Conferencce":"test2","Description":"test","Admin":"919818559899","Moderator":null,"Keywords":"test2","StartDate":"2011-11-18 12:22:33","EndDate":"2011-11-18 14:22:33","Type":"both","MaxAtendee":"0","MinAtendee":"0","RegAtendee":"0","DescVoiceVideo":null,"Rating":null,"Status":"active","ApproveBy":null,"ApprovedOn":"2011-11-15 12:22:33","ApprovedReason":null,"AdminPin":null,"UserPin":null,"PricePerMin":null,"PricePerConf":null,"ReminderStart":null,"AdminJoin":null,"CreatedOn":"2011-11-17 13:31:20","CreatedBy":"1"},"3":{"Id":"1","Conferencce":"test","Description":"tes","Admin":"919818559898","Moderator":null,"Keywords":"test","StartDate":"2011-11-17 12:22:33","EndDate":"2011-11-17 14:22:33","Type":"both","MaxAtendee":"0","MinAtendee":"0","RegAtendee":"0","DescVoiceVideo":null,"Rating":null,"Status":"active","ApproveBy":"1","ApprovedOn":"2011-11-15 12:22:33","ApprovedReason":null,"AdminPin":null,"UserPin":null,"PricePerMin":null,"PricePerConf":null,"ReminderStart":null,"AdminJoin":null,"CreatedOn":"2011-11-17 13:31:15","CreatedBy":"1"}}}

Answer 1

I am not able to iterate through each Map

Instead of treating the three components of the result response as maps, if the names of the keys are consistent and unchanging, I'd define a Java object to match the overall data structure along the following lines. Note this example uses Jackson to handle the JSON-to-Java conversion.

import java.io.File;
import java.math.BigInteger;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;

import org.codehaus.jackson.annotate.JsonAutoDetect.Visibility;
import org.codehaus.jackson.annotate.JsonMethod;
import org.codehaus.jackson.map.ObjectMapper;

public class JacksonFoo
{
  public static void main(String[] args) throws Exception
  {
    ObjectMapper mapper = new ObjectMapper();
    mapper.setVisibility(JsonMethod.ALL, Visibility.ANY);
    mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));

    Response response = mapper.readValue(new File("input.json"), Response.class);

    for (Map.Entry<Integer, Result> entry : response.result.entrySet())
    {
      System.out.printf("Entry %1$d: %2$s\n", entry.getKey(), entry.getValue());
    }
  }
}

class Response
{
  ResponseStatus status;
  Map<Integer, Result> result;
}

enum ResponseStatus
{
  OK, NOT_OK
}

class Result
{
  int Id;
  String Conferencce;
  String Description;
  BigInteger Admin;
  String Moderator;
  String Keywords;
  Date StartDate;
  Date EndDate;
  String Type;
  int MaxAtendee;
  int MinAtendee;
  int RegAtendee;
  String DescVoiceVideo;
  String Rating;
  Status Status;
  String ApproveBy;
  Date ApprovedOn;
  String ApprovedReason;
  String AdminPin;
  String UserPin;
  String PricePerMin;
  String PricePerConf;
  String ReminderStart;
  String AdminJoin;
  Date CreatedOn;
  int CreatedBy;

  @Override
  public String toString()
  {
    return String.format("Id: %1$d, Conferencce: %2$s, Description: %3$s, Admin: %4$d, StartDate: %5$tY-%5$tm-%5$td %5$tH:%5$tM:%5$tS", Id, Conferencce, Description, Admin, StartDate);
  }
}

enum Status
{
  active, inactive
}