从Java中的JSON数组对象获取字符串值

EDIT: I actually found the answer. I can't close the question as I am new. I was able to use Array.getString(i) to return the string value needed. Thanks for all the help.

编辑:我实际上找到了答案。因为我是新人,所以我无法解决这个问题。我能够使用Array.getString(i)返回所需的字符串值。谢谢你的帮助。

I have JSON like this:

我有这样的JSON:

{
  "List": [
    "example1",
    "example2",
    "example3",
    "example4"
  ]
}

And I am trying to get the string value of those objects without using a key. How can I do that? The getString() for jsonObject require a key and I don't have one.

我试图在不使用密钥的情况下获取这些对象的字符串值。我怎样才能做到这一点? jsonObject的getString()需要一个键,而我没有。

3 个解决方案

#1

I assume that you have a file :/home/user/file_001.json

我假设你有一个文件:/home/user/file_001.json

the file contains this : `

该文件包含:`

{"age":34,"name":"myName","messages":["msg 1","msg 2","msg 3"]}

Now let's write a program that reads the file : /home/user/file_001.json and converts its content to a java JSONObject.

现在让我们编写一个程序来读取文件:/home/user/file_001.json并将其内容转换为java JSONObject。

package org.xml.json;

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

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


    public class JsonSimpleRead
    {
        @SuppressWarnings("unchecked")
        public static void main(String[] args)
        {
            JSONParser parser = new JSONParser();
            try
            {
                Object obj = parser.parse(new FileReader("/home/user/file_001.json"));
                JSONObject jsonObject = (JSONObject) obj;
                String name = (String) jsonObject.get("name");
                System.out.println(name);

                long age = (Long) jsonObject.get("age");
                System.out.println(age);

                JSONArray msg = (JSONArray) jsonObject.get("messages");
                Iterator<String> iterator = msg.iterator();
                while (iterator.hasNext())
                {
                    System.out.println(iterator.next());
                }
            }
            catch (FileNotFoundException e)
            {
                e.printStackTrace();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            catch (ParseException e)
            {
                e.printStackTrace();
            }
        }
    }

#2

"List" is your key because that is the property of the outermost JSON object:

“List”是您的密钥,因为它是最外层JSON对象的属性:

JSONObject json = new JSONObject( jsonString );
JSONArray array = json.getArray( "List" );

#3

Another solution:

import org.json.JSONArray;
import org.json.JSONObject;

// example json
String list = "{\"List\": [\"example1\", \"example2\", \"example3\", \"example4\"]}";

// to parse the keys & values of our list, we must turn our list into 
// a json object.
JSONObject jsonObj = new JSONObject(list);

// isolate our list values by our key name (List)
String listValues = jsonObj.getString("List");

// turn our string of list values into a json array (to be parsed)
JSONArray listItems = new JSONArray(listValues);

// now we can print individual values using the getString and 
// the index of the desired value (zero indexed)
Log.d("TAG", listItems.getString(2));

#1