解析JSON并创建对象

时间：2013-08-06 07:47:42

标签： android json parsing

在我的应用程序中，我要解析这个JSON：

programs.json 

{
  "programs": {
    "program": [
      {
        "programNumber": "1",
        "imgURL": "http://www.photovideolife.com/userfiles/Placeholder%2001.jpg",
        "description": "Lorem ipsum dolor sit er elit",
        "episode": [
          {
            "pN": "1",
            "episodeNumber": "1",
            "transmissionName": "Titolo",
            "date": "29 Giu 2013",
            "time": "14:30",
            "channel": "Real Time",
            "channelLogo": "https://lh6.googleusercontent.com/-XSh-9ngYJu4/ThiY-xl2EeI/AAAAAAAABmc/iz04VpL5hOs/s800/realtime.png"
          },
          {
            "pN": "1",
            "episodeNumber": "1",
            "transmissionName": "Titolo",
            "date": "29 Giu 2013",
            "time": "16:30",
            "channel": "DMAX",
            "channelLogo": "http://tv.zam.it/canali/dmax.png"
          },
          {
            "pN": "1",
            "episodeNumber": "2",
            "transmissionName": "Titolo",
            "date": "01 Lug 2013",
            "time": "14:30",
            "channel": "Real Time",
            "channelLogo": "https://lh6.googleusercontent.com/-XSh-9ngYJu4/ThiY-xl2EeI/AAAAAAAABmc/iz04VpL5hOs/s800/realtime.png"
          },
          {
            "pN": "1",
            "episodeNumber": "2",
            "transmissionName": "Titolo",
            "date": "01 Lug 2013",
            "time": "16:30",
            "channel": "DMAX",
            "channelLogo": "http://tv.zam.it/canali/dmax.png"
          }
        ]
      },
      {
        "programNumber": "2",
        "imgURL": "http://mesa.umich.edu/files/mesa/field/image/placeholder2.png",
        "description": "Lorem ipsum dolor sit er elit",
        "Episode": [
          {
            "pN": "2",
            "episodeNumber": "1",
            "transmissionName": "Titolo 1",
            "date": "30 Giu 2013",
            "time": "13:30",
            "channel": "Real Time",
            "channelLogo": "https://lh6.googleusercontent.com/-XSh-9ngYJu4/ThiY-xl2EeI/AAAAAAAABmc/iz04VpL5hOs/s800/realtime.png"
          },
          {
            "pN": "2",
            "episodeNumber": "1",
            "transmissionName": "Titolo 1",
            "date": "30 Giu 2013",
            "time": "18:30",
            "channel": "DMAX",
            "channelLogo": "http://tv.zam.it/canali/dmax.png"
          },
          {
            "pN": "2",
            "episodeNumber": "2",
            "transmissionName": "Titolo 1",
            "date": "01 Lug 2013",
            "time": "13:30",
            "channel": "Real Time",
            "channelLogo": "https://lh6.googleusercontent.com/-XSh-9ngYJu4/ThiY-xl2EeI/AAAAAAAABmc/iz04VpL5hOs/s800/realtime.png"
          },
          {
            "pN": "2",
            "episodeNumber": "2",
            "transmissionName": "Titolo 1",
            "date": "01 Lug 2013",
            "time": "18:30",
            "channel": "DMAX",
            "channelLogo": "http://tv.zam.it/canali/dmax.png"
          }
        ]
      },
      {
        "programNumber": "3",
        "imgURL": "http://wp.contempographicdesign.com/wp_paramount/wp-content/themes/paramount/images/image_placeholder_lrg.jpg",
        "description": "Lorem ipsum dolor sit er elit",
        "Episode": [
          {
            "pN": "3",
            "episodeNumber": "1",
            "transmissionName": "Titolo 2",
            "date": "30 Giu 2013",
            "time": "10:30",
            "channel": "Real Time",
            "channelLogo": "https://lh6.googleusercontent.com/-XSh-9ngYJu4/ThiY-xl2EeI/AAAAAAAABmc/iz04VpL5hOs/s800/realtime.png"
          },
          {
            "pN": "3",
            "episodeNumber": "1",
            "transmissionName": "Titolo 2",
            "date": "30 Giu 2013",
            "time": "17:30",
            "channel": "DMAX",
            "channelLogo": "http://tv.zam.it/canali/dmax.png"
          },
          {
            "pN": "3",
            "episodeNumber": "2",
            "transmissionName": "Titolo 2",
            "date": "01 Lug 2013",
            "time": "10:30",
            "channel": "Real Time",
            "channelLogo": "https://lh6.googleusercontent.com/-XSh-9ngYJu4/ThiY-xl2EeI/AAAAAAAABmc/iz04VpL5hOs/s800/realtime.png"
          },
          {
            "pN": "3",
            "episodeNumber": "2",
            "transmissionName": "Titolo 2",
            "date": "01 Lug 2013",
            "time": "17:30",
            "channel": "DMAX",
            "channelLogo": "http://tv.zam.it/canali/dmax.png"
          }
        ]
      }
    ]
  }
}

我想创建一些对象来存储来自此JSON文件的数据，因此我使用Gson库使这种解析非常容易。我使用这个库创建对象时遇到了麻烦，我创建了4个对象：

  • EpisodeData，我存储此信息（pN，episodeNumber，日期，时间，频道和channelLogo）
  • 这是一集EpisodeData
  • 编程它是一组剧集
  • 我存储阵列程序的程序

这是对象的代码：

EpisodeData.java 

public class EpisodeData implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public String pN, episodeNumber, transmissionName, date, time, channel, channelLogo;
}

Episode.java 

public class Episode implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public EpisodeData[] episodeData;
}

Program.java 

public class Program implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public Episode[] episode; 
}

Programs.java 

public class Programs implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    public Program program;

}

所以我建立了连接（使用AsyncHttpClient）从服务器下载JSON文件，然后我开始解析它，但是我遇到了麻烦。我在这里发布了代码片段：

public void onSuccess(String json) {
   super.onSuccess(json);
   Gson decoder = new Gson();
   Programs programs = decoder.fromJson(json, Programs.class);
   Log.d("PROGRAMS", "" + programs.program);
}

为什么我无法访问Episode和EpisodeData？为什么当我尝试记录programs.program时它返回null？

我希望你能帮我找到解决这个问题的方法 谢谢

2 个答案:

答案 0 :(得分：1)

问题出在基础对象中。它不应该是程序，而是具有Programs属性的另一个对象。除此之外，Programs对象有一个Program as属性数组，而不是单个实例。

基础对象：

public class JsonRootObject {

    public Programs programs;

}

程序对象：

public class Programs implements Serializable {

    private static final long serialVersionUID = 1L;
    public Program []program;

}

程序对象：

public class Program implements Serializable {

    private static final long serialVersionUID = 1L;
    public Episode[] episode; 
}

剧集对象：

public class Episode implements Serializable {

    private static final long serialVersionUID = 1L;
    public String pN, episodeNumber, transmissionName, date, time, channel, channelLogo;
    @Override
    public String toString() {
        return "Episode [pN=" + pN + ", episodeNumber=" + episodeNumber
                + ", transmissionName=" + transmissionName + ", date="
                + date + ", time=" + time + ", channel=" + channel
                + ", channelLogo=" + channelLogo + "]";
    }
}

不需要EpisodeData，因为Episode是最后一个级别。

最后你可以用以下方法解析它：

Gson decoder = new Gson();
JsonRootObject programs = decoder.fromJson(json, JsonRootObject.class);

我在Episode类中添加了一个toString方法来测试解析器，这就是结果：

System.out.println(programs.programs.program[0].episode[0]);

08-06 05:31:58.236: I/System.out(1249): Episode [pN=1, episodeNumber=1, transmissionName=Titolo, date=29 Giu 2013, time=14:30, channel=Real Time, channelLogo=https://lh6.googleusercontent.com/-XSh-9ngYJu4/ThiY-xl2EeI/AAAAAAAABmc/iz04VpL5hOs/s800/realtime.png]

希望有所帮助：）

答案 1 :(得分：0)

我认为您应该在字段pN的声明之上添加@@ SerializedName（“ - pN”），并对其他字段执行此操作。

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