This may to possible of duplicate i need to convert the list to jsonobject like this
{"EmailID":"Djlj#sl.com","PhoneNumber":"870796850","ID":2}
like this how can i achieve this so far what i have tried is :
List<CustomerModel> listobj=new ArrayList<CustomerModel>();
listobj=timetrackerdaoobj.Listtoserver();
String gsonString=new Gson().toJson(listobj, collectionType);
In this method am getting jsonarray like this
[{"EmailID":"Djlj#sl.com","PhoneNumber":"870796850","ID":2}]
But i need format like this:
{"EmailID":"Djlj#sl.com","PhoneNumber":"870796850","ID":2}
Try this way,
String gsonString=new Gson().toJson(listobj, collectionType);
gsonString = gsonString.replace("[","").replace("]","");
System.out.println(gsonString); // here you got expected answer
this may helps you.
You want a JSON Object, and not a JSON Array. So pass only your java object and not the list into your Gson converter :
String gsonString = new Gson().toJson(listobj.get(0), yourType);
I am using the following libraries to create some JSON object.
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
The json I am trying to create is this:
{
"function": "create_contact_group",
"parameters": [{
"user_id": "teer",
"comp_id": "97",
"contact_group_name": "Test01",
"invite_user_list": [{
"invite_user_id": "steve"
}]
}]
}
My function looks like this:
public JSONObject createJSONRequest() {
/* Create json object */
JSONObject jsonObject = new JSONObject();
Map<String, String> map = new HashMap<>();
map.put("user_id", "teer");
map.put("comp_id", "97");
map.put("contact_group_name", "Test01");
List<String> mInviteUserList = new ArrayList<>();
mInviteUserList.add("steve");
/* Create the list of invitee */
Map<String, String> inviteList = new HashMap<>();
for(String user : mInviteUserList) {
inviteList.put("invite_user_id", user);
}
/* Add the invitees into the json array */
JSONArray inviteArray = new JSONArray();
inviteArray.add(inviteList);
/* Add the json array to the json object */
jsonObject.put("invite_user_list", inviteArray);
JSONArray parameterlist = new JSONArray();
parameterlist.add(map);
parameterlist.add(jsonObject);
jsonObject.put("parameters", parameterlist);
jsonObject.put("function", "create_contact_group");
Log.d(TAG, "jsonObject: " + jsonObject.toJSONString());
return jsonObject;
}
However, the function crashes when I get to the following line:
Log.d(TAG, "jsonObject: " + jsonObject.toJSONString())
I think it has something to do with this line here:
parameterlist.add(jsonObject);
Stacktrace:
java.lang.StackOverflowError java.lang.AbstractStringBuilder.enlargeBuffer(AbstractStringBuilder.java:95) at java.lang.AbstractStringBuilder.append0(AbstractStringBuilder.java:132)
at java.lang.StringBuffer.append(StringBuffer.java:126) at org.json.simple.JSONValue.escape(JSONValue.java:266) at org.json.simple.JSONObject.toJSONString(JSONObject.java:116)
Many thanks for any suggestions,
There are a couple of issues in your code.
One issue is that the structure you create in the java code will not match the structure that you show above. This I will try to describe a bit below.
The second issue is that you get a stackoverflow exception (which you know but don't know why).
The stackoverflow exception is thrown cause the program runs out of the stack memory assigned by the computer. Why you ask? Well, cause you create a recursive or cyclic JSON object.
This isn't good, but its not that big a deal cause its kinda easy to fix.
So why does the program throw this exception? Well, look at the following snippet:
JSONArray parameterlist = new JSONArray();
parameterlist.add(map);
parameterlist.add(jsonObject);
jsonObject.put("parameters", parameterlist);
jsonObject.put("function", "create_contact_group");
You create a JSONArray and then add the JSONObject created before to the array.
After that you add the same array to the object that is already in the array.
I expect that you see the issue with that!
So, that should not be done.
And how to fix this? Well, I kinda think its better that I describe how you should write the code to get the structure you are actually asking for, so I'll try do that...
What to do...?
A JSON (JavaScript Object Notation) -object is always declared with this type of brackets: {} a JSON array with [], so, the JSON you are trying to generate should be in the following data types:
{ // <= Root object (a JSON-object).
"function": "create_contact_group", // <= Key in the root-object (where the key is a string and the value a string)
"parameters": [ // <= Key in the root-object (where the key is a string and the value is an array.
{ // <= Object inside the array.
"user_id": "teer", // Key (string/string)
"comp_id": "97", // Key (string/string)
"contact_group_name": "Test01", // Key (string/string)
"invite_user_list": [ // Key (string/array)
{ // Object inside the invite_user_list array
"invite_user_id": "steve" // Key (string/string)
}
]
}
]
}
So when creating the JSON-object in java, you will want to create a root object then add all the diff params inside it.
Adding a value to a JSONObject is done with the JSONObject.put(string, Object) method, where the string is a key and the object a value.
So to start, I would recommend creating the parameters list.
In your case, you use a HashMap for the objects, which is not really wrong, but not really necessary either, I would just stick to a JSONObject, which is not all that different than a HashMap<string, Object>.
So instead of map.put(...), you could do something like:
JSONObject param = new JSONObject();
param.put("user_id", "teer");
param.put("comp_id", "97");
param.put("contact_group_name", "Test01");
Now, one of the objects values should be an array (invite_user_id) and the easiest way to add an array to the object is to create a JSONArray and then just add it.
JSONArray inviteList = new JSONArray();
// Then you need to add an object to the array for each `user` that has invited.
// For-loop here maybe?
JSONObject invitee = new JSONObject();
invitee.put("invite_user_id", user);
inviteList,add(invitee); // This will make it into an array with objects, I.E., [ { "invite_user_id": "Steve" } ]
After creating the invite list, add it to the param object like:
param.put("invite_user_list", inviteList);
// Now, param should be in its own list too, so you should probably create a JSONArray for the params.
// Ill leave that to you, and we pretend we have a list of the param objects named "params".
And then at the end, you create the root object and set its values:
JSONObject root = new JSONObject();
root.put("parameters", params);
root.put("function", "create_contact_group");
And that should be it.
This should create a JSON-string with the structure that you made above. But I would recommend testing (and writing unit tests!) for this (especially as I have written this code in the browser!).
But why?!
I guess I should try to describe why your code was not working as the one I described above.
You start by creating a root object, so far so good (can create it at start or at the time you need it, doesn't really matter), after that you create a HashMap and add the properties to it.
So far this is also legit (you could later create a JSONObject from the map).
In the next part, you create an ArrayList (im not really sure why) and add a name to it, and then another HashMap which you add the single name to (key invite_user_list) inside a for-loop.
This is either not necessary (cause its just one name) or wrong (if there is supposed to be more names in a real life execution of the code), in case of unnecessary, the for-loop shouldn't be there and in case of "not like real life" it should not be added to a Map!
Instead the invieList should have been an array, and each entry added should have been a object which had the "invite_user_id" key set to the name.
After that, you add the inviteList HashMap to a newly created JSONArray, I guess this could be kinda okay, if you only want one object ever in the array, else I would recommend creating it before the loop and add each entry into it!
The inviteArray is then put inside the root object with the key invite_user_list, after that you create another JSONArray and add both the map (your parameters created at the start) and the JSONObject (root) created first of all.
But the thing you do after that, is why you are getting a stackoverflow exception, you add the parameterlist (which contains the jsonObject (root)) to the jsonObject, which makes the jsonObject exist inside an array that is inside itself!
This creates a cyclic JSON structure which will never end if the whole thing was to be unrolled, hence the computer throws the exception.
The structure of the resulting object would also be wrong, cause it would look something like this:
{ // Root (jsonObject)
"invite_user_list": [
{ "invite_user_id": "steve" }
]
"parameters": [
{ // The "map" hashmap
"user_id", "teer",
"comp_id": "97",
"contact_group_name": "Test01"
},
{ // The jsonObject object (which is also the root!)
"invite_user_list": [
{ "invite_user_id": "steve" }
],
"parameters": [
{ // The "map" hashmap
"user_id", "teer",
"comp_id": "97",
"contact_group_name": "Test01"
},
{
// The jsonObject object again (which is also the root and the parent!)
// ... and so on til eternity!
}
],
"function": "create_contact_group"
}
],
"function": "create_contact_group"
}
Extra...
I would like to add here at the end (where I hope you end up after reading the whole wall of text that I wrote above, cause you might have learnt something!) that there is a easier way of doing it.
Now, I haven't used this lib myself, but from what I understand, it should be able to serialize a whole object, the lib can be found at Googles github repos which can be used as a json serializer and convert a class-instance to a json string, then you could just create a class for the whole object and fill it up and serialize it at the end of the function, without using either JSONArray nor JSONObject.
The issue is due to recursion process that occurs when you are trying to add the JsonObject to JsonArray and viceVersa.
The thing you are doing is,
JSONArray parameterlist = new JSONArray();
parameterlist.add(map);
parameterlist.add(jsonObject);
And then
jsonObject.put("parameters", parameterlist);
The problem is when you print the object using jsonObject.toJSONString(), Then at first it will fetch the parameterlist then as jsonObject is part of the keyvalue pair on the parameterlist JsonArray it will refetch the jsonObject which then again fetch the parameterlist and this process continues on and hence causing the StackOverflow Issue.
The Quick Solution is to create new JsonObject while assigning the parameterList,
JSONArray parameterlist = new JSONArray();
parameterlist.add(map);
parameterlist.add(jsonObject);
JSONObject newJson = new JSONObject();
newJson.put("parameters", parameterlist);
System.out.println(newJson.toJSONString());
I have a json object like
{"0":"Andrew Smith"}
how can i get the value means Andrew Smith. I tried a lot but not getting.They key name will get change. I tried in this way
JsonObject jObject = new JsonObject(currentObj);
System.out.println(currentObj.toString());
Iterator i = jObject.keys();
String value = "";
while(i.hasNext()) {
String currentKey = String.valueOf(i.next());
Object currentValue = jObject.get(currentKey);
}
its not going into the loop. So how can i get the value at 0th position.
please help me. Thanks
Try to use Gson:
Map<Integer, String> map = new Gson().fromJson("{\"0\":\"Andrew Smith\"}", new TypeToken<Map<Integer, String>>(){}.getType());
System.out.println(map.entrySet().iterator().next().getValue());
Prints 'Andrew Smith'.
Get the iterator for keys and call getString for the first value
JSONObject obj = new JSONObject("{\"0\":\"Andrew Smith\"}");
Iterator<String> x = obj.keys();
if(x.hasNext())
Log.e("FACEBOOK", obj.getString(x.next()));
Your code works if you just fix all compiler errors.
i.e
It's JSONObject, not JsonObject.
currentObjis not in scope. I suppose you cut it out from somewhere where it is
but replacing it with at string literal will make it easier for other people to
test as well as eliminating one possible source of errors.
Fixing those, putting it in a method and declaring the exception made it work just
fine. Assuming whatever code you started with actually does compile I suggest checking
that the JSONObject in question really is what you think it is.
Following code produces a nested array as a result for keys containing three items:
import org.codehaus.jettison.json.JSONObject;
// ...
JSONObject ret = new JSONObject();
for (Key key:keys) ret.append("blocked",key.id());
The result is:
{"blocked": [[["1"],"2"],"3"]}
Is this expected? If it is, how can I construct a plain array adding item by item?
You need to create a JSONArray object:
JSONObject ret = new JSONObject();
JSONArray arr = new JSONArray();
arr.put("1");
arr.put("2");
arr.put("3");
ret.put("blocked", arr);
The result is:
{"blocked":["1","2","3"]}
It's curious because the API says the following:
Append values to the array under a key. If the key does not exist in the
JSONObject, then the key is put in the JSONObject with its value being a
JSONArray containing the value parameter. If the key was already
associated with a JSONArray, then the value parameter is appended to it.
But it doesn't work correctly. When I do:
JSONObject o = new JSONObject();
o.append("arr", "123");
o.append("arr", "456");
I get an Exception saying that "JSONObject[arr] is not a JSONArray". It looks like there is a bug.
I ran into a similar problem. You should use the put method; not the append method. And, of course, you should create a JSONArrray and use that as the second argument of the put method.
Consider following piece of code:
JSONObject json = new JSONObject();
json.put("one", 1);
json.put("two", 2);
json.put("three", 3);
If i print the jsonobject it prints like this
{"three":"1","two":"2","one":"1"}
But i want like this.
{"one":"1","two":"2","three":"3"}
Please help. Thanks in advance.
The documentation at http://www.json.org/javadoc/org/json/JSONObject.html says:
A JSONObject is an unordered collection of name/value pairs.
In other words, properties of an object are accessed by name, not by position and the default serialized form does not guarantee any specific order.
Strict positioning comes only with arrays:
JSONArray json = new JSONArray();
json.put("1");
json.put("2");
json.put("3");
json.toString(); // results in ["1", "2", "3"]
The easiest workaround to solve your problem is to use the sortedKeys() method and by iterating the JSONObject key by key, produce the JSON string manually in what ever order necessary. Implementing a custom Comparator might help also.