Convert JSON array[array[String]] to Java array

Question

I have a JavaScript JSON array[array[String]] called jsonArray in my JSP1.jsp.

I am converting jsonArray to a String jsonArrayStr using JSON.stringify(jsonArray) in JSP1.jsp.

I am passing jsonArrayStr as a parameter while calling another JSP JSP2.jsp this way-

"JSP2.do?jsonArrayStr="+jsonArrayStr

In JSP2.jsp, I am doing this-

String jsonArrayStr = request.getParameter("jsonArrayStr");

Now how do I convert jsonArrayStr to Java array (JSP2.jsp doesn't contain any JavaScript code)

Summary-

I have a JavaScript JSON Array in a JSP1.jsp, which I want to access as a normal Java array/arraylist in JSP2.jsp. How do I achieve this?

Are you starting out with a one-dimensional array, or a two-dimensional array? Does your array contain just Strings, or does it contain arrays that contain strings? JSON.stringify() on e one-dimensional array would look like: ["a", "b", "c", "x", "y", "z"] JSON.stringify() on a two-dimensional array would look like: [["a", "b", "c"],["x"],["y","z"]] — sdouglass
– sdouglass, Commented Feb 8, 2013 at 6:30
@user1649068 you want to create a array of java objects from jsonarray? — Parvathy
– Parvathy, Commented Feb 8, 2013 at 12:32

sdouglass · Accepted Answer · 2013-02-09 00:50:01Z

OK, so you have a two-dimensional array of strings represented as a JSON like this stored in a Java String:

[["a", "b", "c"],["x"],["y","z"]]

You need to somehow parse or "deserialize" that value into a Java String[][]. You can use a library like from http://www.json.org/java/index.html or http://jackson.codehaus.org/ or you can try to do it manually. Manually could be a little tricky but not impossible. The json.org library is very simple and might be good enough. The code would be something like this (I haven't tried/tested this):

JSONArray jsonArray = new JSONArray(jsonArrayStr); // JSONArray is from the json.org library
String[][] arrayOfArrays = new String[jsonArray.length()][];
for (int i = 0; i < jsonArray.length(); i++) {
    JSONArray innerJsonArray = (JSONArray) jsonArray.get(i);
    String[] stringArray = new String[innerJsonArray.length()];
    for (int j = 0; j < innerJsonArray.length(); j++) {
        stringArray[j] = innerJsonArray.get(j);
    }
    arrayOfArrays[i] = stringArray;
}

TheWhiteRabbit · Accepted Answer · 2013-02-08 04:59:00Z

0

somethingk like this

ArrayList<String> strings= 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());
   } 
} 

String[] Stringarray = strings.toArray(new String[strings.size()]);

answered Feb 8, 2013 at 4:59

TheWhiteRabbit

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9 Comments

AlwaysALearner Over a year ago

According to my question, what is JSONObject here? jsonArray or jsonArrayStr?

AlwaysALearner Over a year ago

So, u mean to say there is no need for me to stringify() the json object? I will be able to directly access the JSONobject across JSP pages without passing them?

TheWhiteRabbit Over a year ago

yes, directly pass the jsonArray as request parameter to jsp2 and in jsp2 do as mentioned above :)

AlwaysALearner Over a year ago

are you talking about net.sf.json.JSONArray

AlwaysALearner Over a year ago

This is how I am passing the array value to another JSP as u said- "JSP2.do?jsonArray="+jsonArray;

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