Json Array not properly generated

Question

I have written java code for generating json of my searched data from file.But its not generating exact JsonArray. Its like

[{"item":"1617"},{"item":"1617"}]

instead of

[{"item":"747"},{"item":"1617"}].

Here 1617 is last item which is fetched from file.

JSONArray ja = new JSONArray();
JSONObject jo = new JSONObject();

while (products.readRecord())
{
    String productID = products.get("user");
    int j = Integer.parseInt(productID);
    if(j == userId) {
        itemid = products.get("item");
        jo.put("item",itemid);
        ja.add(jo);
    }
}  

out.println(ja);
products.close();

Saket Patel · Accepted Answer · 2012-03-21 20:55:30Z

6

you are actually creating one jSONobject object to handle two objects, shouldn't you need to create JSONObjects in the while loop? something like this, so every iteration in while loop will create a new JSONObject and add it to JSONArray

JSONArray ja = new JSONArray();

while (products.readRecord())
{
    String productID = products.get("user");
    int j = Integer.parseInt(productID, 10);

    if(j == userId)
    {
         JSONObject jo = new JSONObject();
         itemid = products.get("item");
         jo.put("item", itemid);
         ja.add(jo);
    }

}  

out.println(ja);
products.close();

Extra:

i am not sure how java does conversion for string to integer, but i think you should always specify radix when using parseInt so the strings like '09' will not be treated as octal value and converted to wrong value (atleast this is true in javascript :))

Integer.parseInt(productID, 10);

edited Mar 21, 2012 at 20:55

answered Mar 21, 2012 at 20:44

Saket Patel

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1 Comment

Guillaume Polet Over a year ago

+1. Even better, move the instantiation to the if-block, avoiding to instantiate unnecessary objects

Guillaume Polet · Accepted Answer · 2012-03-21 20:44:08Z

3

You must re-instantiate your JSonObject inside the loop because when you modify it you modify the underlying object which is referenced several times by your array. Move your JSONObject jo = new JSONObject(); inside the loop and it should work fine.

answered Mar 21, 2012 at 20:44

Guillaume Polet

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Comments

jabal · Accepted Answer · 2012-03-21 20:46:10Z

2

Place JSONObject jo = new JSONObject(); inside the loop:

while (products.readRecord())
{
  JSONObject jo = new JSONObject();
  String productID = products.get("user");
  int j = Integer.parseInt(productID);
  // etc

}

answered Mar 21, 2012 at 20:46

jabal

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