Question

我正在尝试解析json文件以使用Java提取某些字段。但是，我正在获取某些字段（标签）的空值，例如国家/地区，site_type，replies_count，partners_count等。我尝试在json对象之后使用.toString（），但我仍然不断获取NULL值。

有人可以帮助我修复代码吗？作为json的示例如下：

{
"posts": [
{
  "thread": {
    "uuid": "5cf0a3152a01d082500a46b358e984610ce87c9c",
    "url": "https://www.cnn.com/videos/cnnmoney/2018/05/27/active-shooter-video-game-backlash.hln",
    "site_full": "www.cnn.com",
    "site": "cnn.com",
    "site_section": "http://feeds.feedburner.com/cnn/wYAn",
    "site_categories": [
      "media"
    ],
    "section_title": "CNN.com - RSS Channel - HP Hero",
    "title": "New 'school shooter' game stirs outrage",
    "title_full": "New 'school shooter' game stirs outrage",
    "published": "2018-05-27T15:15:00.000+03:00",
    "replies_count": 0,
    "participants_count": 0,
    "site_type": "news",
    "country": "US",
    "spam_score": 0.0,
    "main_image": "https://cdn.cnn.com/cnnnext/dam/assets/180527080429-video-game-active-shooter-super-tease.jpg",
    "performance_score": 3,
    "domain_rank": 81,
    "social": {
      "facebook": {
        "likes": 399,
        "comments": 0,
        "shares": 399
      },
      "gplus": {
        "shares": 0
      },
      "pinterest": {
        "shares": 2
      },
      "linkedin": {
        "shares": 0
      },
      "stumbledupon": {
        "shares": 0
      },
      "vk": {
        "shares": 0
      }
    }
  },
  "uuid": "5cf0a3152a01d082500a46b358e984610ce87c9c",
  "url": "https://www.cnn.com/videos/cnnmoney/2018/05/27/active-shooter-video-game-backlash.hln",
  "ord_in_thread": 0,
  "author": "",
  "published": "2018-05-27T15:15:00.000+03:00",
  "title": "New 'school shooter' game stirs outrage",
  "text": "MUST WATCH New 'active shooter' video game sparks backlash Thousands of people have petitioned to stop the release of a new video game which takes on the point of view of a school gunman.",
  "highlightText": "",
  "highlightTitle": "",
  "language": "english",
  "external_links": [],
  "entities": {
    "persons": [],
    "organizations": [],
    "locations": []
  },
  "rating": null,
  "crawled": "2018-05-27T16:05:21.021+03:00"
}
],
"total_count": "122"

}

这是我的代码（我正在使用json.simple。* API解析json）：

import java.io.FileReader;
import java.util.Iterator;

import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;



public class JSONRetriever {

public static void main(String[] args) {
    JSONParser jsonParser = new JSONParser();
    Object object;

    try {

        object = jsonParser.parse(new FileReader("C:\\sample.json"));
        JSONObject jsonObject = (JSONObject) object;

        JSONArray posts = (JSONArray) jsonObject.get("posts");

        Iterator itr = posts.iterator();

        while (itr.hasNext()) {

            Object slide = itr.next();
            JSONObject jsonObject2 = (JSONObject) slide;
            JSONObject thread = (JSONObject) jsonObject2.get("thread");

            String uuid = (String) thread.get("uuid");
            String url = (String) thread.get("url");
            String site_full = (String) thread.get("site_full");
            String site = (String) thread.get("site");
            String site_section = (String) thread.get("site_section");

            String section_title = (String) jsonObject2.get("section_title");
            String title = (String) jsonObject2.get("title");
            String title_full = (String) jsonObject2.get("title_full");
            String published = (String) jsonObject2.get("published");
            String replies_count = (String) jsonObject2.get("replies_count");
            String participants_count = (String) jsonObject2.get("participants_count");
            String site_type = (String) jsonObject2.get("site_type");
            String country = (String) jsonObject2.get("country");
            String spam_score = (String) jsonObject2.get("spam_score");

            JSONObject social = (JSONObject) jsonObject2.get("social");
            System.out.println("section_title: " + section_title);
            System.out.println("title: " + title);
            System.out.println("title_full: " + title_full);
            System.out.println("published: " + published);
            System.out.println("replies_count: " + replies_count);
            System.out.println("participants_count: " + participants_count);
            System.out.println("site_type: " + site_type);
            System.out.println("country: " + country);
            System.out.println("spam_score: " + spam_score);

            System.out.println("uuid: " + uuid);
            System.out.println("url: " + url);
        }


    }catch(Exception e)
    {
        e.printStackTrace();
    }

}
}

Answer 1

您的字段位于您的“线程”对象中，而不是“ jsonObject2”中，例如，使用：

 String country = (String) thread.get("country");

为什么解析JSON时会得到NULL值

}

1 个答案: