spring - java duplicate key in same json object

Question

I am trying to parse a JSON response using jsonObject library in Java, but receiving exception with duplicated key. I need to parse this JSON as it is, without any loop and without any conversion. Some solution stated that I have to convert those values to array, so I need your suggestion. Is there any library that can parse my json which has duplicated key without any change? This is my code :

BufferedReader in = new BufferedReader(
        new InputStreamReader(c.getInputStream()));  //stream to resource
    
String inputLine;
StringBuffer res = new StringBuffer();
    
while ((inputLine = in.readLine()) != null) {
    res.append(inputLine);
}
    
JSONObject json = new JSONObject(res.toString());
    

my error response :

Exception in thread "main" org.json.JSONException: Duplicate key "Account"
    at org.json.JSONObject.putOnce(JSONObject.java:1121)
    at org.json.JSONObject.<init>(JSONObject.java:208)
    at org.json.JSONTokener.nextValue(JSONTokener.java:362)
    at org.json.JSONObject.<init>(JSONObject.java:208)
    at org.json.JSONTokener.nextValue(JSONTokener.java:362)

question from:https://stackoverflow.com/questions/65914310/java-duplicate-key-in-same-json-object

Answer 1

you can make use of net.sf.json.JSONObject. It will accept JSON with the duplicate key.

This library will retain the duplicated values by storing them into arrays. If multiple same keys are available it will create one key with all the values as Array.

And also the coding part is just a single line. Once you parsed the json using net.sf.json.JSONObject then you can supply this to jackson library.

JSONObject jsonObject = JSONObject.fromObject( "{ "a": "a", "a": { "b": {},"b": true}}" );

System.out.println( "net.sf.json.JSONObject: " + jsonObject );

JsonNode jsonNode = new ObjectMapper().readTree( jsonObject.toString() );

System.out.println( "com.fasterxml.jackson.databind.JsonNode" + jsonNode );

Output:

net.sf.json.JSONObject: {"a":["a",{"b":[{},true]}]}

com.fasterxml.jackson.databind.JsonNode{"a":["a",{"b":[{},true]}]}

Maven dependency of net.sf.json

<dependency>
    <groupId>net.sf.json-lib</groupId>
    <artifactId>json-lib</artifactId>
    <version>2.4</version>
    <classifier>jdk15</classifier>
</dependency>