How to dynamically simplify json using java? - java

I have received a json string like so:
{
"data": [
{
"name": "Order",
"value": "2"
},
{
"name": "Address",
"value": "182"
},
{
"name": "DNS",
"value": "null"
},
{
"name": "SSID",
"value": "work"
},
{
"name": "Protocol",
"value": "0"
},
{
"name": "Key",
"value": ""
},
{
"name": "carrier",
"value": "undefined"
},
{
"name": "SSH",
"value": "1"
},
{
"name": "ntp_addr",
"value": ""
},
{
"name": "Name",
"value": ""
}
]
}
I used stringify on an html response and this is what I have to parse. As you can see, it is pretty redundant; I would much rather { "Order":"2" } than { "name":"Order","value":"2" } ... So an array of name-value pairs, instead of an array of objects.
Is there a way I can dynamically format this response so that it will be easier to parse?
What 'd like is to be able to say:
JSONObject jsonObject = new JSONObject(jsonResponse);
JSONArray data = jsonObject.getJSONArray("data");
for (int i = 0; i < data.length(); i++) {
JSONObject dataObject = data.getJSONObject(i);
String order = dataObject.getString("Order");
String address = dataObject.getString("Address");
// etc...
}
But the current format makes it almost impossible to parse. I'd need loops within loops.

I'd like to use com.google.gson library. And this response easy to parse with it:
private final JsonParser PARSER = new JsonParser();
public void parse(String jsonString) {
JsonObject dataObject = PARSER.parse(jsonString).getAsJsonObject();
JsonArray dataArray = dataObject.get("data").getAsJsonArray();
dataArray.iterator().forEachRemaining(element -> {
String name = element.getAsJsonObject().get("name").getAsString();
String value = element.getAsJsonObject().get("value").getAsString();
}
}
Or you can simply use TypeAdapters for json deserialization directly in the object.

Something like this should do the trick
JSONObject jsonObject = new JSONObject(jsonResponse);
JSONArray data = jsonObject.getJSONArray("data");
JSONObject simplifiedDataObject = new JSONObject();
for (int i = 0; i < data.length(); i++) {
JSONObject dataField = data.getJSONObject(i);
simplifiedDataObject.put(dataField.getString("name"), dataField.get("value"));
}
You just iterate over each element in data, use the name field as the field on a new JSONObject and simply retrieve the value using the value key.

Related

Java - How to Parse empty Nested Json Array

I am trying to Parse below JSON data to String in Java using (GSON) Library, I am able to parse all JSON fields data except one of the JSON Array. I want to check if it's null/empty then in String variable store null value, if it's not then store the original value.
Input JSON Data:
{
"expand": "schema,names",
"startAt": 0,
"maxResults": 50,
"total": 37875,
"issues": [
{
"id": "1190",
"key": "GDS-81",
"fields": {
"issuetype": {
"id": "2170",
"name": "Service Request with Approvals",
"subtask": false
},
"customfield_29805": {
"id": "26",
"name": "Issue - First Response",
"completedCycles": []
}
}
}
]
}
Code that I have done so far,
JsonObject object = (JsonObject) new JsonParser().parse(jsonResponse);
JsonArray issuesArray = object.getAsJsonArray("issues");
for(int i=0; i<issuesArray.size(); i++) {
JsonObject currentissues = (JsonObject) issuesArray.get(i);
String Issue_Id = (String) currentissues.get("id").toString().replace("\"", "");
String Issue_Key = (String) currentissues.get("key").toString().replace("\"", "");
String Issue_Type = (String) currentissues.get("fields").getAsJsonObject().get("issuetype").getAsJsonObject().get("name").getAsString();
JsonObject customfield = (JsonObject) currentissues.get("fields").getAsJsonObject().get("customfield_29805");
JsonArray completedCyclesArray= customfield.getAsJsonArray("completedCycles");
String Issue_FirstResponseStartTime = (completedCyclesArray.size() > 0) ? completedCyclesArray.getAsString() : "NULL";
}
However when I execute code I get below error on line :JsonObject customfield
java.lang.ClassCastException: com.google.gson.JsonNull cannot be cast to com.google.gson.JsonObject
[![UpdatedCode StackTrace][1]][1]
[1]: https://i.stack.imgur.com/2wY0S.jpg
you dont need to explicitly , cast JsonElement to JsonObject instead use getAsJsonArray , Once you get your array, you can iterate through all the elements of it.
You also need to handle null check for completedCyclesArray before checking its siz else it will give you the NPE , I have fixed that as well.
Please find the modified working code as below
JsonParser parser = new JsonParser();
JsonArray array = parser.parse(jsonResponse).getAsJsonArray();
for(JsonElement e : array) {
JsonObject currentissues = (JsonObject) e;
String Issue_Id = (String) currentissues.get("id").toString().replace("\"", "");
String Issue_Key = (String) currentissues.get("key").toString().replace("\"", "");
String Issue_Type = (String) currentissues.get("fields").getAsJsonObject().get("issuetype").getAsJsonObject().get("name").getAsString();
JsonObject customfield = (JsonObject) currentissues.get("fields").getAsJsonObject().get("customfield_29805");
JsonArray completedCyclesArray= customfield.getAsJsonArray("completedCycles");
String Issue_FirstResponseStartTime = (null != completedCyclesArray && completedCyclesArray.size() > 0) ? completedCyclesArray.getAsString() : "NULL";
}
}
Please find my working solution for the updated json request(which not an array but nested json request)
JsonObject object = (JsonObject) new JsonParser().parse(jsonResponse);
JsonArray issuesArray = object.getAsJsonArray("issues");
String expand = object.get("expand").toString();
String startAt = object.get("startAt").toString();
String maxResults = object.get("maxResults").toString();
String total = object.get("total").toString();
System.out.println(String.format("expand %s , startAt %s, maxResults %s, total %s", expand, startAt, maxResults, total));
IntStream.range(0, issuesArray.size()).mapToObj(i -> (JsonObject) issuesArray.get(i)).forEach(currentissues -> {
String Issue_Id = (String) currentissues.get("id").toString().replace("\"", "");
String Issue_Key = (String) currentissues.get("key").toString().replace("\"", "");
String Issue_Type = (String) currentissues.get("fields").getAsJsonObject().get("issuetype").getAsJsonObject().get("name").getAsString();
JsonObject customfield = (JsonObject) currentissues.get("fields").getAsJsonObject().get("customfield_29805");
JsonArray completedCyclesArray = customfield.getAsJsonArray("completedCycles");
String Issue_FirstResponseStartTime = (completedCyclesArray.size() > 0) ? completedCyclesArray.toString() : "NULL";
System.out.println(String.format("Issue_Id %s , Issue_Key %s, Issue_Type %s, Issue_FirstResponseStartTime %s", Issue_Id, Issue_Key, Issue_Type, Issue_FirstResponseStartTime));
});
and this is the output I got :
expand "schema,names" , startAt 0, maxResults 50, total 37875 Issue_Id
1190 , Issue_Key GDS-81, Issue_Type Service Request with Approvals,
Issue_FirstResponseStartTime NULL
Please see my complete working code here complete code
for both the secnarios
Empty completedCycles
{
"expand": "schema,names",
"startAt": 0,
"maxResults": 50,
"total": 37875,
"issues": [
{
"id": "1190",
"key": "GDS-81",
"fields": {
"issuetype": {
"id": "2170",
"name": "Service Request with Approvals",
"subtask": false
},
"customfield_29805": {
"id": "26",
"name": "Issue - First Response",
"completedCycles": []
}
}
}
]
}
Non Empty completedCycles
{
"expand": "schema,names",
"startAt": 0,
"maxResults": 50,
"total": 37875,
"issues": [
{
"id": "1190",
"key": "GDS-81",
"fields": {
"issuetype": {
"id": "2170",
"name": "Service Request with Approvals",
"subtask": false
},
"customfield_29805": {
"id": "26",
"name": "Issue - First Response",
"completedCycles": [{"name":"abc"},{"name": "xyz"}]
}
}
}
]
}
Try adding getAsJsonObject() at the end of that statement.

Android JSON parsing Json Array is [] Throws Null Pointer Exception while parsing, How to write in Proper way?

I have complex API that i parse and show in list view,I will be struggle to parse JSONArray.Here i will be in struggle following Json Array which is inside the posts json object "tags_name": ["Activities"],,some object it will come like "tags_name": [], this.Kindly review my question. My API and code is below. Presently i will implemented parsing code with model class. Once fix this issue i have to write list view coding please help me. May be my question formation is in silly way. please it look like means give some suggestion to frame question. Thanks in Advance.
MyAPI:
{
"status": true,
"nextpage": 0,
"count": 31,
"data": {
"postlist": [{
"posts": {},
"tags_name": ["Activities"],
"images_count": 3,
"images": [],
"post_user": [],
"is_encourage_user": true,
"encourage_feed_id": "1093"
},
{
"posts": {"id": "4647"},
"tags_name": [],
"images_count": 0,
"images": [],
"post_user": [],
"is_encourage_user": true,
"encourage_feed_id": "992"
}
]
},
"token": "wqeeqweqweqweqweqsfsdfsdf"
}
My Method for Parsing
private void parsingPostValues(String responseStatus) throws JSONException {
JSONObject responseObject = new JSONObject(responseStatus);
JSONObject datObject = responseObject.getJSONObject("data");
JSONArray postArr = new JSONArray(datObject.getString("postlist"));
for (int i = 0; i < postArr.length(); i++) {
JSONObject tempPostObject = postArr.getJSONObject(i);
JSONObject postObject = tempPostObject.getJSONObject("posts");
//setTag Array- this is the functional area i'm in bottle-neck.
try {
JSONArray tagNameArr = tempPostObject.getJSONArray("tags_name");
//ArrayList<Bean> tagListdata = new ArrayList<Bean>(tagNameArr.length());
if (tagNameArr.length()>0) {
for (int tagInfo = 0; tagInfo < tagNameArr.length(); tagInfo++) {
// listdata.add(tagNameArr.get(i).toString());
String tagme = "";
//Bean tagBean = new Bean();
//tagBean.setTagsArray((tagme.isEmpty() ? tagNameArr.get(tagInfo).toString() : "null")); //tagBean.setTagsArray(tagNameArr.get(tagInfo).toString());
//tagListdata.add(tagBean);
//beanAccess.setTagsArray(tagNameArr.get(tagInfo));
System.out.println("Tags Array:"+tagInfo+":"+tagNameArr.get(tagInfo));
}
//beanAccess.setTagsArray(tagListdata);
}
} catch (Exception e) {
e.printStackTrace();
}
}
replace this
JSONArray postArr = new JSONArray(datObject.getString("postlist"));
To
JSONArray postArr = datObject.getJSONArray("postlist");
Replace
String imgCount = tempPostObject.getString("images_count");
String is_encourage_user = tempPostObject.getString("is_encourage_user");
To
String imgCount = postObject.getString("images_count");
String is_encourage_user = postObject.getString("is_encourage_user");
It will work for you.

Join two jsons based on element

I have two json files. I need to parse and join the json into a single structure
lineage.json
{
"lineage": [{
"sourceColumnId": "VMB_BESTADDRESS.SNAPSHOT_TS",
"description": "",
"targetColumnId": "VMB_BESTADDRESSUSAGE.NXREINS"
},
{
"sourceColumnId": "DSL_RECORD_SOURCES.MAMACT",
"description": "",
"targetColumnId": "G2_ZUMADF00.MAMACT"
},
{
"sourceColumnId": "DSL_RECORD_SOURCES.MAMADE",
"description": "",
"targetColumnId": "G2_ZUMADF00.HDF_S_POL_GEN"
}]
}
column.json
{
"column": [{
"ID": 39700,
"columnId": "VMB_BESTADDRESS.SNAPSHOT_TS",
"column": "SNAPSHOT_TS",
"dataType": "String",
"length": "",
"table": "VMB_BESTADDRESS",
},
{
"ID": 39701,
"columnId": "VMB_BESTADDRESSUSAGE.NXREINS",
"column": "NXREINS",
"dataType": "String",
"length": "",
"table": "VMB_BESTADDRESSUSAGE",
},
{
"ID": 39702,
"columnId": "VMB_BESTADDRESSUSAGE.PKADDRESSCODE",
"column": "PKADDRESSCODE",
"dataType": "String",
"length": "",
"table": "VMB_BESTADDRESSUSAGE",
}]
}
I need to join the two jsons such that for every match of sourcecolumnId and targetcolumnid in column the following json structure must be populated
{
output:{
sourceColumnId:VMB_BESTADDRESS.SNAPSHOT_TS,
sourceColumnName:SNAPSHOT_TS,
targetColumnId:VMB_BESTADDRESSUSAGE.NXREINS,
targetColumnNameNXREINS,
}
}
I need to join lookup two json to get the output such that
sourceColumnName -> column name from column.json whose columnId and sourceColumnId are same.
similarly for targetcolumnName also.
String str = "xxx"; // column.json
JSONArray jsonArrayColumn = JSON.parseObject(str);
Map<String, JSONObject> column = new HashMap(); // {id:name}
for(int i = 0; i < jsonArrayColumn.size(); i++){ // loop
JSONObject obj = jsonArrayColumn.getJSONObject(i);
column.put(obj.getString("columnId"), obj.getString("column"));
}
String str2 = "xxx"; // lineage.json
JSONArray jsonArrayLineage = JSON.parseObject(str2);
JSONArray resultArray = new JSONArray();
for(int i = 0; i < jsonArrayLineage.size(); i++){ // loop
JSONObject lineageObj = jsonArrayLineage.getJSONObject(i);
JSONObject obj = new JSONObject();
obj.put("sourceColumnId", lineageObj.get("sourceColumnId"));
obj.put("sourceColumnName", column.get(lineageObj.get("sourceColumnId")));
obj.put("targetColumnId", lineageObj.get("targetColumnId"));
obj.put("targetColumnName", column.get(lineageObj.get("targetColumnId")));
}
The resultArray is what you want.

Parsing jsonobject when entire json is an array?

I am using gson-2.5 for this. There is a slight difference in the format of these two jsons, where in the first one;
"usethis": [
{
"id": 111,
"text": "some text that i would like",
},
{
"id": 222,
"text": "someothertextiwouldlike",
}
]
I would have parsed this to get "text" this way, and everything would be ok;
JsonParser jp = new JsonParser();
JsonElement root = jp.parse(listcontents);
JsonObject rootobj = root.getAsJsonObject();
JsonArray items = rootobj.get("usethis").getAsJsonArray();
for(int i = 0; i < items.size(); i++) {
JsonObject item = items.get(i).getAsJsonObject();
String thetext = item.get("text").getAsString();
System.out.println("text: " + thetext + "\n");
}
The difference is that in the second one, I have nothing to get as the rootobject unlike in the first where I used "usethis";
[
{
"id": 111,
"text": "some text that i would like",
},
{
"id": 222,
"text": "someothertextiwouldlike",
}
]
And setting
rootobj.get("usethis").getAsJsonArray();
to
rootobj.get("").getAsJsonArray();
just gives me an error. How would I be able to parse the second json?
JsonElement is just a superclass of JsonArray and JsonObject.
JsonArray items = root.getAsJsonArray();
should do what you want.

Accessing json string in java and creating hashmap Android

I have a JSON string and I am trying to retrieve information from it. Json String looks like this.
JSON STRING :
{
"information": {
"device": {
"id": 0
},
"user": {
"id": 0
},
"data": [
{
"datum": {
"id": "00GF001",
"history_id": "9992BH",
"name": "abc",
"marks": 57,
"class": "B",
"type": "Student"
}
},
{
"datum": {
"id": "72BA9585",
"history_id": "78NAH2",
"name": "ndnmanet",
"marks": 70,
"class": "B",
"type": "Student"
}
},
{
"datum": {
"id": "69AHH85",
"history_id": "NN00E3006",
"name": "kit",
"department": "EF003",
"class": "A",
"type": "Employee"
}
},
{
"datum": {
"id": "09HL543",
"history_id": "34QWFTA",
"name": "jeff",
"department": "BH004",
"class": "A1",
"type": "Employee_HR"
}
}
]
}
}
I am trying to access data JSONArray and respective Datum from it. I differentiated each datum as per type such as student, employee etc and push information in hashmap.
I successfully did it in javascript but in Java I am struggle abit.
When I am trying to access JSONArray it throws exception
try {
JSONObject data = new JSONObject(dataInfo);
// Log.d(TAG, "CHECK"+data.toString());
JSONObject info = data.optJSONObject("information");
if(info.getJSONArray("data").getString(0).equals("Student") > 0) //exception here
Log.d(TAG, "Data"+ data.getJSONArray("data").length()); //exception here too
for(int m = 0; m < data.length(); m++){
// for(int s = 0; s < data[m].ge)
}
} catch (JSONException j){
j.printStackTrace();
}
Any pointers to create hashmap respective type I have. Appreciated
If you're trying to access the type field of a datum object, you'll want something like this:
JSONObject data = new JSONObject(dataInfo); // get the entire JSON into an object
JSONObject info = data.getJSONObject("information"); // get the 'information' object
JSONArray dataArray = info.getJSONArray("data"); // get the 'data' array
for (int i = 0; i < dataArray.length(); i++) {
// foreach element in the 'data' array
JSONObject dataObj = dataArray.getJSONObject(i); // get the object from the array
JSONObject datum = dataObj.getJSONObject("datum"); // get the 'datum' object
String type = datum.getString("type"); // get the 'type' string
if ("Student".equals(type)) {
// do your processing for 'Student' here
}
}
Note that you'll have to deal with exception handling, bad data, etc. This code just shows you the basics of how to get at the data that you're looking for. I separated each individual step into its own line of code so that I could clearly comment what is happening at each step, but you could combine some of the steps into a single line of code if that is easier for you.
if dataInfo is the json you posted, then you have to access information and from information, you can access data:
JSONObject data = new JSONObject(dataInfo);
JSONObject info = data.optJSONObject("information");
if (info != null) {
JSONArray dataArray = info.optJSONArray("data")
}

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