使用Java读取多个对象JSON [英] Read Multiple Objects JSON with Java

问题描述

我需要使用以下结构读取Java中的JSON文件：

  {id_user：10， level：medium，text：hello 10} 
 {id_user：20，level：medium，text：hello 20} 
 {id_user：30，level：medium，text：hello 30} 
  

谢谢！

---

[已编辑]

我有这段代码，但只能读取第一个JSON对象，我需要逐一读取三个对象。

  private void loadJSONFile（）{
 FileReader fileReader = new FileReader（pathFile）; 
 try（JsonReader jsonReader = new JsonReader（fileReader））{
 jsonReader.beginObject（）; 
 while（jsonReader.hasNext（））{
 String name = jsonReader.nextName（）; 
 if（name.equals（filter_level））{
 System.out.println（jsonReader.nextString（））; 
} else if（name.equals（text））{
 System.out.println（text：+ jsonReader.nextString（））; 
} else {
 jsonReader.skipValue（）; 
} 
} 
 jsonReader.endObject（）; 
 jsonReader.close（）; 
} 
} 
  

谢谢！ <解决方案

我知道这已经差不多一年了:)但是我实际上是在重新发布一个答案，因为我遇到了和你一样的问题

我有这个text.txt文件 - 我知道这不是一个有效的Json数组 - 但是如果你看，你会看到这个文件的每一行都是Json对象

  {Sensor_ID：874233，Date：Apr 29,2016 08:49:58 Info Log1} 
 {Sensor_ID：34234，Date：Apr 29,2016 08:49:58 Info Log12} 
 {Sensor_ID：56785，Date ：Apr 29,2016 08:49:58 Info Log13} 
 {Sensor_ID：235657，Date：Apr 29,2016 08:49:58 Info Log14} 
 {Sensor_ID：568678，Date：Apr 29,2016 08:49:58 Info Log15} 
  

现在我想读取上面的每一行，并将名称Sensor_ID和Date解析为Json格式。经过长时间的搜索，我有以下几点：

试试看，并在控制台上查看结果。我希望它有帮助。

  package reading_file; 
 
 import java.io. *; 
 import java.util.ArrayList; 
 
 import org.json.simple.JSONObject; 
 import org.json.simple.parser.JSONParser; 
 import org.json.simple.parser.ParseException; 
 
 public class file_read {
 public static void main（String [] args）{
 ArrayList< JSONObject> json = new ArrayList< JSONObject>（）; 
 JSONObject obj; 
 //要打开的文件的名称。 
 String fileName =C：\\ Users\\aawad\\workspace\\kura_juno\\data_logger\\\\\\\\\\\\\\\\\\\\\\\ Apr_28_2016\\ 。文本 ; 
 
 //这将一次引用一行
 String line = null; 
 
尝试{
 // FileReader以默认编码读取文本文件。 
 FileReader fileReader = new FileReader（fileName）; 
 
 //总是将FileReader包装在BufferedReader中。 
 BufferedReader bufferedReader = new BufferedReader（fileReader）; $（$）
 $ b while（（line = bufferedReader.readLine（））！= null）{
 obj =（JSONObject）new JSONParser（）。parse（line）; 
 json.add（obj）; 
 System.out.println（（String）obj.get（Sensor_ID）+：+ 
（String）obj.get（Date））; 
} 
 //总是关闭文件。 
 bufferedReader.close（）; 
} 
 catch（FileNotFoundException ex）{
 System.out.println（Unable to open file'+ fileName +'）; 
} 
 catch（IOException ex）{
 System.out.println（Error reading file'+ fileName +'）; 
 //或者我们可以这样做：
 // ex.printStackTrace（）; 
} catch（ParseException e）{
 // TODO自动生成的catch块
 e.printStackTrace（）; 
} 
} 
} 
  

I need to read a JSON file in Java with the following structure:

{"id_user":"10","level":"medium","text":"hello 10"}
{"id_user":"20","level":"medium","text":"hello 20"}
{"id_user":"30","level":"medium","text":"hello 30"}

Thanks!.

---

[POST-EDITED]

I have this code but only read the first JSON Object, I need read the three objects one by one.

private void loadJSONFile(){
        FileReader fileReader = new FileReader(pathFile);
        try (JsonReader jsonReader = new JsonReader(fileReader)) {
            jsonReader.beginObject();
            while (jsonReader.hasNext()) {
                String name = jsonReader.nextName();
                if (name.equals("filter_level")) {
                    System.out.println(jsonReader.nextString());
                } else if (name.equals("text")) {
                    System.out.println("text: " + jsonReader.nextString());
                } else {
                    jsonReader.skipValue();
                }
            }
            jsonReader.endObject();
            jsonReader.close();
        }
    }

thanks!

解决方案

I know it has been almost one year for this post :) but i am actually reposing again as an answer because i had this problem same as you Yuan

I have this text.txt file - I know this is not a valid Json array - but if you look, you will see that each line of this file is a Json object in its case alone.

{"Sensor_ID":"874233","Date":"Apr 29,2016 08:49:58 Info Log1"}
{"Sensor_ID":"34234","Date":"Apr 29,2016 08:49:58 Info Log12"}
{"Sensor_ID":"56785","Date":"Apr 29,2016 08:49:58 Info Log13"}
{"Sensor_ID":"235657","Date":"Apr 29,2016 08:49:58 Info Log14"}
{"Sensor_ID":"568678","Date":"Apr 29,2016 08:49:58 Info Log15"}

Now I want to read each line of the above and parse the names "Sensor_ID" and "Date" into Json format. After long search, I have the following:

Try it and look on the console to see the result. I hope it helps.

package reading_file;

import java.io.*;
import java.util.ArrayList;

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

public class file_read {
public static void main(String [] args) {
    ArrayList<JSONObject> json=new ArrayList<JSONObject>();
    JSONObject obj;
    // The name of the file to open.
    String fileName = "C:\\Users\\aawad\\workspace\\kura_juno\\data_logger\\log\\Apr_28_2016\\test.txt ";

    // This will reference one line at a time
    String line = null;

    try {
        // FileReader reads text files in the default encoding.
        FileReader fileReader = new FileReader(fileName);

        // Always wrap FileReader in BufferedReader.
        BufferedReader bufferedReader = new BufferedReader(fileReader);

        while((line = bufferedReader.readLine()) != null) {
            obj = (JSONObject) new JSONParser().parse(line);
            json.add(obj);
            System.out.println((String)obj.get("Sensor_ID")+":"+
                               (String)obj.get("Date"));
        }
        // Always close files.
        bufferedReader.close();         
    }
    catch(FileNotFoundException ex) {
        System.out.println("Unable to open file '" + fileName + "'");                
    }
    catch(IOException ex) {
        System.out.println("Error reading file '" + fileName + "'");                  
        // Or we could just do this: 
        // ex.printStackTrace();
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}
}

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