I'm having trouble with gson:
For example I have this output from website:
[["connected"], ["user1":"Hello"], ["user2":"Hey"], ["disconnected"]]
But I want parse this JSON and output something like this:
connected
user1 says: Hello
user2 says: Hey
disconnected
I quicly wrote this code:
public static void PrintEvents(String id){
String response = Post.getResponse(Server()+"events?id="+id,"");
// response is [["connected"],["user1":"Hello"],["user2":"Hey"],["disconnected"]]
JsonElement parse = (new JsonParser()).parse(response); //found this in internet
int bound = ????????????; // Should be 4
for (int i=1;i<=bound;i++){
String data = ???????????;
if (data == "connected" || data == "disconnected") then {
System.out.println(data);
}else if(?????==2){// to check how many strings there is, if it's ["abc","def"] or ["abc"]
String data2 = ??????????????;
System.out.println(data+" says: "+data2);
}else{
//something else
}
};
}
What should I insert to these parts with question marks to make code work?
I cannot find any way to make it work...
Sorry for my bad English.
EDIT: Changed response to [["connected"], ["user1","Hello"], ["user2","Hey"], ["disconnected"]]. Earlier response was not valid JSON.
The response that you have pasted is not a valid json. paste it in http://www.jsoneditoronline.org/ and see the error.
Please find the below code snippet:
public static void printEvents(String id)
{
String response = "[[\"connected\"] ,[\"user1:Hello\"],[\"user2:Hey\"],[\"disconnected\"]]";
JsonElement parse = (new JsonParser()).parse(response); //found this in internet
int bound = ((JsonArray)parse).size(); // Should be 4
for (int i = 0; i < bound; i++) {
String data = ((JsonArray)parse).get(0).getAsString();
if (data.equals("connected") || data.equals("disconnected")) {
System.out.println(data);
continue;
}
String[] splittedData = data.split(":");
if (splittedData.length
== 2) {// to check how many strings there is, if it's ["abc","def"] or ["abc"]
System.out.println(splittedData[0] + " says: " + splittedData[1]);
}
/*
*else{
* your else logic goes here
* }
* */
}
}
Couple of suggestions:
If you are new to json world, use jackson instead of Gson.
the response is not a good design. Slightly correct json:
{
"firstKey": "connected",
"userResponses": [
{
"user1": "hey"
},
{
"user2": "hi"
}
],
"lastKey": "disconnected"
}
Also try to define pojos , instead of working inline with json.
You need to define a separate class like this:
class MyClass{
String name;
String value;
}
and then:
List<MyClass> myclasses = new Gson().fromJson(response, new TypeToken<List<MyClass>>(){}.getType());
then
for(MyClass myclass: myclasses){
...
}
Related
To make it into a valid JSON
"{containerId:81,params:[{parameterName:vinay,valueInDesignMode:where actor_id<50,valueInRunMode:where actor_id<100},{parameterName:name,valueInDesignMode:where actor < =10,valueInRunMode:},{parameterName:nameID,valueInDesignMode:,valueInRunMode:}]}"
Expected output
{"containerId":81,"params":[{"parameterName":"vinay","valueInDesignMode":"where actor_id<50","valueInRunMode":"where actor_id<100","containerId":81},{"parameterName":"name","valueInDesignMode":"where actor < =10","valueInRunMode":""},{"parameterName":"nameID","valueInDesignMode":"","valueInRunMode":""}]}
Please check this:
public static void main(String[] args) {
String inputJson = "{containerId:81,params:[{parameterName:vinay,valueInDesignMode:where actor_id<50,valueInRunMode:where actor_id<100},{parameterName:name,valueInDesignMode:where actor < =10,valueInRunMode:},{parameterName:nameID,valueInDesignMode:,valueInRunMode:}]}";
String outputJson =
inputJson
.replace(" ", "")
.replaceAll("([\\w]+):", "\"$1\":")
.replaceAll(":([\\w|<|=]+)", ": \"$1\"")
.replaceAll("\"([\\d]+)\"", "$1")
.replace(":}", ": \"\"}")
.replace(":]", ": \"\"]")
.replace(":,", ": \"\",");
System.out.println(outputJson);
}
Although this code gives your desired result but you can find better solutions.
To convert the above Object to JSON you need to make the key and value as a string like the below and later you can parse the JSON to evaluate the conditional statements.
{
"containerId":81,
"params":[
{
"parameterName":"vinay",
"valueInDesignMode":"where actor_id<50",
"valueInRunMode":"where actor_id<100"
},
{
"parameterName":"name",
"valueInDesignMode":"where actor < =10",
"valueInRunMode":null
},
{
"parameterName":"nameID",
"valueInDesignMode": null,
"valueInRunMode":null
}
]}
so as part of some work I've been doing I was given a file with WebServices that are being used in a Swift application. I have zero familiarity with WebServices and only know Java through syntax understanding. I need to call one of these gets with a parameter from the swift application. What I'm trying to figure out first and foremost is how I can call one of these webservices with a parameter from the URL it's associated with. For example down below I want to call the method
http://localhost:9000/ListVehicleByPlateNumber
and I want to specify the parameter through the URL say something like
http://localhost:9000/ListVehicleByPlateNumber?para="123"
But this doesn't assign any value to the parameter and I'm not getting results. If I hardcode so that the string used in the function is = "123" it gives me the results I'm looking for. I just need to know how I can pass this parameter through the url, syntax-wise.
Routes file
GET /ListVehicleByPlateNumber controllers.NewVehicle.listVehicleByPlateNumber(para: String ?="")
Controller
public Result listVehicleByPlateNumber(String para){
NewVehicleModel v = new NewVehicleModel();
List<NewVehicleModel> vehiclesC = v.searchByPlateVehicle(para);
ObjectNode wrapper = Json.newObject();
ObjectNode msg = Json.newObject();
if(vehiclesC != null) {
msg.set("VehicleList", toJson(vehiclesC));
wrapper.set("success", msg);
return ok(wrapper);
}else{
msg.put("error", "There are no vehicles with the plate number");
wrapper.set("error", msg);
return badRequest(wrapper);
}
}
Where it's called
public List<NewVehicleModel> searchByPlateVehicle(String plateNumber){
Transaction t = Ebean.beginTransaction();
List<NewVehicleModel> vehicles = new ArrayList<>();
try {
String sql = "SELECT V.idNewVehicle, V.VehicleType,V.PlateNumber,V.VehicleJurisdiction,V.State,V.Vin,V.Year, " +
"V.Make,V.modelos,V.RegistrationNumber,V.InsuranceCompany,V.PurchaseDate,V.ExpirationDate,V.idPersonaFK " +
"FROM NewVehicle V " +
"WHERE V.PlateNumber = :plateNumber";
RawSql rawSql = RawSqlBuilder.parse(sql)
.columnMapping("V.idNewVehicle", "idNewVehicle")
.columnMapping("V.State", "state")
.columnMapping("V.VehicleType", "vehicleType")
.columnMapping("V.PlateNumber", "plateNumber")
.columnMapping("V.VehicleJurisdiction", "vehicleJurisdiction")
.columnMapping("V.Vin", "vin")
.columnMapping("V.Year", "year")
.columnMapping("V.Make", "make")
.columnMapping("V.modelos", "modelos")
.columnMapping("V.RegistrationNumber", "registrationNumber")
.columnMapping("V.InsuranceCompany", "insuranceCompany")
.columnMapping("V.PurchaseDate", "purchaseDate")
.columnMapping("V.ExpirationDate", "expirationDate")
.columnMapping("V.idPersonaFK", "idPersonaFK")
.create();
Query<NewVehicleModel> query = Ebean.find(NewVehicleModel.class);
query.setRawSql(rawSql)
.setParameter("plateNumber", plateNumber);
vehicles = query.findList();
t.commit();
}
catch (Exception e){
System.out.println(e.getMessage());
}finally {
t.end();
}
return vehicles;
}
Found my own answer. I ended up casting from Integer to String here's how it looks in routes
GET /ListVehicleByPlateNumber/:para controllers.NewVehicle.listVehicleByPlateNumber(para: Integer )
Controller
public Result listVehicleByPlateNumber(int para){
String p = String.valueOf(para);
URI Format for value 123 example.
http://localhost:9000/ListVehicleByPlateNumber/123
This is a very straightforward question, but this error is very mysterious to me as I have not been able to find a solution or anyone else who has had this problem. I've also used a very similar technique in another activity and it worked just fine. I am making an android application which makes a POST request to a server. The response is a JSONObject that must be parsed into a number and another JSONObject which must also be parsed, and its values assigned to an array of CurrentGame objects. The first call to getJSONObject works fine, but calling getString on that JSONObject returns the following error:
java.lang.NullPointerException: Attempt to write to field 'java.lang.String com.xxxxx.xxxxx.CurrentGame.oppEmail' on a null object reference
Here is my java code:
private void handleResponse(JSONObject response){
int numGroups = 0;
try{
numGroups = response.getInt("Number");
}catch(JSONException e){
e.printStackTrace();
}
Log.i("Number of Groups", String.valueOf(numGroups));
CurrentGame[] currentGames = new CurrentGame[numGroups];
JSONObject current;
int yourTurn = 0;
for(int i = 0; i < numGroups; i++){
try{
current = response.getJSONObject(String.valueOf(i));
Log.i("Current JSONObject: ", String.valueOf(current));
if(current.has("OppEmail")){
currentGames[i].oppEmail = current.getString("OppEmail");
}
if(current.has("OppName")) {
currentGames[i].oppName = current.getString("OppName");
}
if(current.has("Group")) {
currentGames[i].group = current.getString("Group");
}
if(current.has("YourTurn")) {
yourTurn = current.getInt("YourTurn");
}
if(yourTurn == 0){
currentGames[i].yourTurn = true;
}
else{
currentGames[i].yourTurn = false;
}
}
catch (JSONException e){
e.printStackTrace();
}
}
}
Shouldn't the JSONObject.has() check at least be preventing this error?
I know the first getInt() and getJSONObject are working. Heres the Log:
06-21 21:58:56.644 20116-20116/com.xxxxx.xxxxx D/Response:﹕ {"Number":2,"0":{"Group":"Test Group 1","OppEmail":"xxxxx#xxxxx.edu","OppName":"MikeyP","YourTurn":0},"1":{"Group":"Test Group 2","OppEmail":"xxxxx#xxxxx.edu","OppName":"MikeyP","YourTurn":1}}
06-21 21:58:56.644 20116-20116/com.xxxxxx.xxxxxt I/Number of Groups﹕ 2
06-21 21:58:56.644 20116-20116/com.xxxxx.xxxxx I/Current JSONObject﹕ {"Group":"Test Group 1","OppEmail":"xxxxxx#xxxxx.edu","OppName":"MikeyP","YourTurn":0}
Here's the server code:
$games['Number'] = $numgames;
if($numgames > 0){
$i = 0;
while($row = mysqli_fetch_array($getgames)){
$currGame['Group'] = $row['GroupName'];
// Get the opponent's email and username
if($row['Player1'] != $email){
$opponent = $row['Player1'];
$currGame['OppEmail'] = $opponent;
$sql = "SELECT Username FROM users WHERE Email = '".$opponent."'";
$username = mysqli_query($conn, $sql);
$row2 = mysqli_fetch_assoc($username);
$currGame['OppName'] = $row2['Username'];
}
else if($row['Player2'] != $email){
$opponent = $row['Player2'];
$currGame['OppEmail'] = $opponent;
$sql = "SELECT Username FROM users WHERE Email = '".$opponent."'";
$username = mysqli_query($conn, $sql);
$row2 = mysqli_fetch_assoc($username);
$currGame['OppName'] = $row2['Username'];
}
// Determine if it is this player's turn
if($row['CurrentPlayer'] != $email){
$currGame['YourTurn'] = 0;
}
else{
$currGame['YourTurn'] = 1;
}
$games[$i] = $currGame;
$i++;
}
}
//Echo array of groups
header('Content-Type: application/json');
$response = json_encode($games);
echo $response;
Thank you in advance for any ideas as to what I'm doing wrong here. I know similar questions have been asked about getString() returning null, but having read them all I'm still very stumped.
Problem is caused by :
currentGames[i].oppEmail = current.getString("OppEmail");
line.
Because currentGames Array is initialized with size 2 but not added any item of type CurrentGame.
Instead of using currentGames[i].oppEmail create a object of CurrentGame class add all values then add it in currentGames Array like:
CurrentGame objCurrentGame=new CurrentGame();
if(current.has("OppEmail")){
objCurrentGame.oppEmail = current.getString("OppEmail");
}
... same for other fields
...
//Add objCurrentGame to Array
currentGames[i]=objCurrentGame;
Parsing json this way is not robust and error prone, it is recommended to use such libraries as
Gson
Jackson
Retrofit
as these open source libraries offer stable implementation for such purposes and there is no need to reinvent the wheel yourself.
example:
YourPojoClass obj = new Gson().fromJson("{SomeJsonString}", YourPojoClass.class);
In this way, you get the strongly typed pojo instance.You don't even need write the POJO class yourself, and there are many online service that can generate the POJO class out of json strings:
http://www.jsonschema2pojo.org/
http://pojo.sodhanalibrary.com/
I have a parser to parse the below response,the issue is i am able to parse only first table dataset not able to parse second or later table dataset,not sure where looping is going wrong.the xml response is like
anyType{schema=anyType{element=anyType{complexType=anyType{choice=anyType{element=anyType{complexType=anyType{sequence=anyType{element=anyType{}; element=anyType{}; element=anyType{}; element=anyType{}; element=anyType{}; }; }; }; }; }; }; }; diffgram=anyType{NewDataSet=anyType{Table=anyType{RemMessage=Exeed Discount Limit on Invoice dated on 05/03/2015 for C SHAH , from 3 - Lokhandwala Showroom; InvM_Id=77693; DocType=3; PrmR_TypeId=3; PrmR_Id=1820; }; **Table=anyType{RemMessage=Exeed Discount Limit on Invoice dated on 14/03/2015 for G P SHAH , from 3 - Khar Showroom; InvM_Id=77800; DocType=3; PrmR_TypeId=3; PrmR_Id=1865; };** Table=anyType{RemMessage=Exeed Discount Limit on Invoice dated on 14/03/2015 for DOONGARSHI SHAH , from 3 - Khar Showroom; InvM_Id=77801; DocType=3; PrmR_TypeId=3; PrmR_Id=1866; }; }; }; }
my parsing code is not parsing entire response properly,The code is
public class KSoap2ResultParser {
public static void parseBusinessObject(String input, Object output) throws NumberFormatException, IllegalArgumentException, IllegalAccessException, InstantiationException{
System.out.println("input----> " +input);
Class theClass = output.getClass();
Field[] fields = theClass.getDeclaredFields();
for (int i = 0; i < fields.length; i++) {
Type type=fields[i].getType();
System.out.println("type--" +type);
fields[i].setAccessible(true);
//detect String
if (fields[i].getType().equals(String.class)) {
String tag = fields[i].getName() + "="; //"s" is for String in the above soap response example + field name for example Name = "sName"
System.out.println("fff------------"+tag);
if(input.contains(tag)){
String strValue = input.substring(input.indexOf(tag)+tag.length(), input.indexOf(";", input.indexOf(tag)));
System.out.println("RemMessage------------"+strValue);
if(strValue.length()!=0){
fields[i].set(output, strValue);
}
}
}
//detect int or Integer
if (type.equals(Integer.TYPE) || type.equals(Integer.class)) {
String tag = fields[i].getName() + "="; //"i" is for Integer or int in the above soap response example+ field name for example Goals = "iGoals"
if(input.contains(tag)){
String strValue = input.substring(input.indexOf(tag)+tag.length(), input.indexOf(";", input.indexOf(tag)));
System.out.println("strvalue------------"+strValue);
if(strValue.length()!=0){
fields[i].setInt(output, Integer.valueOf(strValue));
}
}
}
//detect float or Float
if (type.equals(Float.TYPE) || type.equals(Float.class)) {
String tag = "f" + fields[i].getName() + "=";
if(input.contains(tag)){
String strValue = input.substring(input.indexOf(tag)+tag.length(), input.indexOf(";", input.indexOf(tag)));
if(strValue.length()!=0){
fields[i].setFloat(output, Float.valueOf(strValue));
}
}
}
}
}
}
and i am calling from
String response=androidHttpTransport.responseDump;
SoapObject obj=(SoapObject)envelope.getResponse();
for(int i=0; i < obj.getPropertyCount(); i++) {
GetReminder rem = new GetReminder();
KSoap2ResultParser.parseBusinessObject(obj.getProperty(i).toString(),rem);
reminders.add(rem);
}
there is an issue in parsing please help me to correct it.
First, FYI, the response you get is not XML.
You have 2 solutions to properly parse the response:
1- Get the WS response as an actual XML
To do that see this thread. And then use a proper XML DOM parser to process the response and build the Java objects.
2- Do it directly with a SOAP api
Looking for the best way, I came across this with tips that are relevant to your problem.
Look at parsing array elements. In your case, you can change your code:
Change the line:
KSoap2ResultParser.parseBusinessObject(obj.getProperty(i).toString(),rem);
by:
KSoap2ResultParser.parseBusinessObject((SoapObject)obj.getProperty(i),rem);
And change the signature of method parseBusinessObject(SoapObject pojoSoap, Object obj). Then in the method, for each type, e.g. for String:
if(strValue.length()!=0){
fields[i].set(output, strValue);
}
by:
if(strValue.length()!=0){
String fieldName = fields[i].getName();
String fieldValue = pojoSoap.getProperty(fieldName).toString();
fields[i].set(output, fieldValue);
}
I need to parse a large XML file (probably going to use StAX in Java) and output it into a delimited text file and I have a couple of design questions. First here is an example of the XML
<demographic>
<value>001</value>
<question>Name?</question>
<value>Bob</value>
<question>Last Name?</question>
<value>Smith</value>
<followUpQuestions>
<question>Middle Init.</question>
<value>J</value>
</followUpQuestions>
</demographic>
this would need to be outputted (in the delimited output file) as
001~Bob~Smith~J
so here are my questions:
How can I distinguish between all the different "value" tags, since the tag names are not unique. Currently I tried to resolve this by having 'state' variables that turn on once they pass question-text such as "Name?", however this approach doesnt really work for the first value since I have to check to make sure the 'name' and 'lastName' states are off to ensure I'm getting the first value.
Everytime the client changes the text of the questions (which happens) I have to change the code and recompile it. Is there anyway to avoid this? Maybe save the questions-text in a text file that the program reads in?
Can this be scalable? I need to extract over 100 values and the XML files are usually about 2 gigs large.
Thank you, in advance, for your help (from a Java and XML newbie)!!
UPDATE: here is my attempt to code the solution, can someone please help to streamline? There has to be a less messy way to do this:
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import java.io.*;
class TestJavaForStackOverflow{
boolean nameState = false,
lastNameState = false,
middleInitState = false;
String name = "",
lastName = "",
middleInit = "",
value = "";
public void parse() throws IOException, XMLStreamException{
XMLInputFactory factory = XMLInputFactory.newInstance();
XMLStreamReader streamReader = factory.createXMLStreamReader(
new FileReader("/n04/data/revmgmt/anthony/scripts/Java_Programs/TestJavaForStackOverflow.xml"));
while(streamReader.hasNext()){
streamReader.next();
if(streamReader.getEventType() == XMLStreamReader.START_ELEMENT){
if("demographic".equals(streamReader.getLocalName())){
parseDemographicInformation(streamReader);
}
}
}
System.out.println(value + "~" + name + "~" + lastName + "~" + middleInit);
}
public void parseDemographicInformation(XMLStreamReader streamReader) throws XMLStreamException {
while(streamReader.hasNext()){
streamReader.next();
if(streamReader.getEventType() == XMLStreamReader.END_ELEMENT){
if("demographic".equals(streamReader.getLocalName())){
return;
}
}
else if(streamReader.getEventType() == XMLStreamReader.START_ELEMENT){
if("question".equals(streamReader.getLocalName())){
streamReader.next();
if("Name?".equals(streamReader.getText())){
nameState = true;
}
else if("Last Name?".equals(streamReader.getText())){
lastNameState = true;
}
else if("Middle Init.".equals(streamReader.getText())){
middleInitState = true;
}
}
else if("value".equals(streamReader.getLocalName())){
streamReader.next();
if(nameState){
name = streamReader.getText();
nameState = false;
}
else if (lastNameState){
lastName = streamReader.getText();
lastNameState = false;
}
else if (middleInitState){
middleInit = streamReader.getText();
middleInitState = false;
}
else {
value = streamReader.getText();
}
}
}
}
}
public static void main(String[] args){
TestJavaForStackOverflow t = new TestJavaForStackOverflow();
try{t.parse();}
catch(IOException e1){}
catch(XMLStreamException e2){}
}
}
I think the flags are not very scalable if you have a lot of different questions to parse, and neither are the global variables to hold the results... if you have 100 questions then you'll need 100 variables, and when they change over time it will be a bear to keep them up to date. I would use a map structure to hold the result, and another one to hold the correspondence between each question text and the corresponding field you are trying to capture (this is not actual Java, just an approximation):
public Map parseDemographicInformation(XmlStream xml, Map questionMap) {
Map record = new Map();
String field = "id";
while((elem = xml.getNextElement())) {
if(elem.tagName == "question") {
field = questionMap[elem.value];
} else if(elem.tagName == "value") {
record[field] = elem.value;
}
}
return record;
}
Then you have something like this to output the result:
String[] fieldsToOutput = { "id", "firstName", "lastName" }; // ideally read this from a file too so it can be changed dynamically
// ...
for(int i=0; i < fieldsToOutput.length; i++){
if(i > 0)
System.out.print("~");
System.out.print(record[fieldsToOutput[i]]);
}
System.out.println();