Convert JSON Array to Normal Java List

Converting JSONarray to ArrayList

ArrayList<String> listdata = new ArrayList<String>();     
JSONArray jArray = (JSONArray)jsonObject; 
if (jArray != null) { 
   for (int i=0;i<jArray.length();i++){ 
    listdata.add(jArray.getString(i));
   } 
} 

Convert Json Array to normal Java list

ArrayList<String> list = new ArrayList<String>();     
JSONArray jsonArray = (JSONArray)jsonObject; 
if (jsonArray != null) { 
   int len = jsonArray.length();
   for (int i=0;i<len;i++){ 
    list.add(jsonArray.get(i).toString());
   } 
} 

How to convert a jsonArray into List String Java?

I assume JSONArray comes from Android. You can just do this:

ArrayList<String> list = new ArrayList<String>();
JSONArray jsonArray = (JSONArray)jsonObject;
if (jsonArray != null) {
    int len = jsonArray.length();
    for (int i=0;i<len;i++){
        list.add(jsonArray.get(i).toString());
    }
}

Source: Convert Json Array to normal Java list

How to convert the simple.JSONArray to normal JSONArray in Java

org.json.simple and org.json are different and incompatible libraries.

The use of org.json.simple shouldn't be recommended as it returns all of its values as an Object, whereas org.json allows to dictate what type to return.

The solution is not to use the org.json.simple.parser.JSONParser (delete all of the org.json.simple imports) but to read the String from the relevant file and pass that to the org.json.JSONArray directly, like so:

String json = FileUtils.readFileToString(new File( "src/main/resources/SampleRequest.json"), "UTF-8" );
JSONArray array = new JSONArray(json);

As you can see, I like to use the FileUtils from the following package for simplicity's sake, so add this dependency:

<!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.8.0</version>
</dependency>

How to convert json to ArrayList object in Java?

You need to use:

Product p = new Product(); 
p.setId( jsonArray.getJSONObject(i).getInt("id") );
p.setName( jsonArray.getJSONObject(i).getString("name") );
list.add(p)

All inside the loop, because you need to create a new product each time.

Convert JSONArray to String Array

Take a look at this tutorial.
Also you can parse above json like :

JSONArray arr = new JSONArray(yourJSONresponse);
List<String> list = new ArrayList<String>();
for(int i = 0; i < arr.length(); i++){
    list.add(arr.getJSONObject(i).getString("name"));
}

Convert JSONArray to String[] Array

i'm put the JSONArray to the string toString(), and i'm convert by regular expression like this ..

public String getImg(String d){
    return rubahFormat(d).split(",");
}

public String rubahFormat(String d){
    return d.replaceAll("[\\[\\]\\\"]","");
}

Thx ..

JsonArray to Arraylist Conversion

Internally this JsonArray implements list interface so type casting to List is perfectly fine. Moreover iterating each and every element will access list one by one which will be overhead(Performance impact).

If you need alternate way you can use toCollection static method from the same JsonArray class

Generic Method to Convert JSON Array String to List in java

Don’t reinvent the wheel:

public static <T> List<T> stringToClassList(String data, Class<T> convertType, ObjectMapper mapper) {
    return mapper.readValue(data, mapper.getTypeFactory().constructCollectionType(List.class, convertType));
}

Also note fixing the return type from List<?> (less useful) to List<T> (useful).

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Your test method can also be simplified and improved:

@Test
public void testStringToClassList() {
    String input = "[\"foo\", \"bar\"]";
    List<String> expected = Arrays.asList("foo", "bar");
    Assert.assertEquals(expected, stringToClassList(input, String.class));
}

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