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ystem.JSONException: Expected List<Railway.stations> but found "" at [line:1, column:2]
Hi,
Please suggest how to handle this type error in Apex.when a received blank value in response i get the error which is pasted below:-
Controller:-
public class Railway {
public string city {get; set;}
public string result {get; set;}
public JsonParser resset {get; set;}
Public void invoke(){
string endpoint='https://indianrailways.p.rapidapi.com/findstations.php?station='+city;
Http http=new Http();
HttpRequest req=new HttpRequest ();
Req.setHeader('X-RapidAPI-Host', 'indianrailways.p.rapidapi.com');
Req.setHeader('X-RapidAPI-Key', 'b6aaeccc96msh12c221cffd99255p151d80jsn32a04d0da645');
req.setEndpoint(endpoint);
req.setMethod('GET');
HttpResponse res=http.send(req);
result=res.getBody();
if(result!=null || result!=''){
resset =(JsonParser)system.JSON.deserialize(result,JsonParser .class);
}
else
{
ApexPages.addmessage(new ApexPages.message(ApexPages.severity.WARNING,'Please enter correct value'));
}
}
public class JsonParser{
public list<stations> stations{get;set;}
}
public class stations{
public String stationCode{get;set;}
public String stationName{get;set;}
}
}
VF PAGE:-
<apex:page controller="Railway">
<apex:form >
<apex:inputText value="{!city}"/>
<apex:commandButton action="{!invoke}" value="Invoke" rerender="i"/> <br></br>
</apex:form>
<apex:pageBlock title="STATION NAMAE AND CODES" id="i">
<apex:pageBlockSection title="STATION NAMAE AND CODES" columns="4">
<apex:pageBlockTable value="{!resset.stations}" var="a" rendered="{! !ISNULL(resset)}">
<apex:column headerValue="stationName" value="{!a.stationName}" />
<apex:column headerValue="stationCode" value="{!a.stationCode}" />
</apex:pageBlockTable>
</apex:pageBlockSection>
</apex:pageBlock> <br></br><br></br>
{!result} <br></br><br></br>
</apex:page>
ERROR:-
ystem.JSONException: Expected List<Railway.stations> but found "" at [line:1, column:2]
Error is in expression '{!invoke}' in component <apex:commandButton> in page irailway: Class.System.JSON.deserialize: line 15, column 1
Class.Railway.invoke: line 17, column 1
Please suggest how to handle this type error in Apex.when a received blank value in response i get the error which is pasted below:-
Controller:-
public class Railway {
public string city {get; set;}
public string result {get; set;}
public JsonParser resset {get; set;}
Public void invoke(){
string endpoint='https://indianrailways.p.rapidapi.com/findstations.php?station='+city;
Http http=new Http();
HttpRequest req=new HttpRequest ();
Req.setHeader('X-RapidAPI-Host', 'indianrailways.p.rapidapi.com');
Req.setHeader('X-RapidAPI-Key', 'b6aaeccc96msh12c221cffd99255p151d80jsn32a04d0da645');
req.setEndpoint(endpoint);
req.setMethod('GET');
HttpResponse res=http.send(req);
result=res.getBody();
if(result!=null || result!=''){
resset =(JsonParser)system.JSON.deserialize(result,JsonParser .class);
}
else
{
ApexPages.addmessage(new ApexPages.message(ApexPages.severity.WARNING,'Please enter correct value'));
}
}
public class JsonParser{
public list<stations> stations{get;set;}
}
public class stations{
public String stationCode{get;set;}
public String stationName{get;set;}
}
}
VF PAGE:-
<apex:page controller="Railway">
<apex:form >
<apex:inputText value="{!city}"/>
<apex:commandButton action="{!invoke}" value="Invoke" rerender="i"/> <br></br>
</apex:form>
<apex:pageBlock title="STATION NAMAE AND CODES" id="i">
<apex:pageBlockSection title="STATION NAMAE AND CODES" columns="4">
<apex:pageBlockTable value="{!resset.stations}" var="a" rendered="{! !ISNULL(resset)}">
<apex:column headerValue="stationName" value="{!a.stationName}" />
<apex:column headerValue="stationCode" value="{!a.stationCode}" />
</apex:pageBlockTable>
</apex:pageBlockSection>
</apex:pageBlock> <br></br><br></br>
{!result} <br></br><br></br>
</apex:page>
ERROR:-
ystem.JSONException: Expected List<Railway.stations> but found "" at [line:1, column:2]
Error is in expression '{!invoke}' in component <apex:commandButton> in page irailway: Class.System.JSON.deserialize: line 15, column 1
Class.Railway.invoke: line 17, column 1
Even if there is no Stations are found also you external system giving the below result in response body that is the reason if the condition getting passed:
{"stations":""}
so that i am checking further your response with below lines:
Map<String, Object> results = (Map<String, Object>)JSON.deserializeUntyped(result);
if(results.get('stations') != ''){
List<Object> lststations = (List<Object>)results.get('stations');
system.debug('@@@ lststations ==> ' + lststations.size());
if(lststations.size() > 0){
resset =(JsonParser)system.JSON.deserialize(result,JsonParser.class);
}
If there is stations are found then you will get the response as below. you capture these this things in your debug log.
{"stations":[{"stationName":"TIRUNELVELI TOWN","stationCode":"TYT"},{"stationName":"TIRUNELVELI","stationCode":"TEN"}]}
Please mark this as best answer if it helps to you!!!
Thanks,
Maharajan.C
All Answers
I have made some of the changes in your class:
now try the below code it will work.
public class Railway {
public string city {get; set;}
public string result {get; set;}
public JsonParser resset {get; set;}
Public void invoke(){
string endpoint='https://indianrailways.p.rapidapi.com/findstations.php?station='+city;
Http http=new Http();
HttpRequest req=new HttpRequest ();
Req.setHeader('X-RapidAPI-Host', 'indianrailways.p.rapidapi.com');
Req.setHeader('X-RapidAPI-Key', 'b6aaeccc96msh12c221cffd99255p151d80jsn32a04d0da645');
req.setEndpoint(endpoint);
req.setTimeout(12000); // To Avoid read time out error
req.setMethod('GET');
HttpResponse res=http.send(req);
result=res.getBody();
system.debug('result ==> '+ result);
if(result!=null && result!=''){
system.debug('@@@ result ==> '+ result);
Map<String, Object> results = (Map<String, Object>)JSON.deserializeUntyped(result);
if(results.get('stations') != ''){
List<Object> lststations = (List<Object>)results.get('stations');
system.debug('@@@ lststations ==> ' + lststations.size());
if(lststations.size() > 0){
resset =(JsonParser)system.JSON.deserialize(result,JsonParser.class);
}
}
else
{
resset = null;
}
}
else
{
ApexPages.addmessage(new ApexPages.message(ApexPages.severity.WARNING,'Please enter correct value'));
}
}
public class JsonParser{
public list<stations> stations{get;set;}
}
public class stations{
public String stationCode{get;set;}
public String stationName{get;set;}
}
}
Thanks,
Maharajan.C
I have a query why followng check not working
if(result!=null && result!='')
Because i am checking there that result string is '' or null then why code enters in block if the result in ''.
Even if there is no Stations are found also you external system giving the below result in response body that is the reason if the condition getting passed:
{"stations":""}
so that i am checking further your response with below lines:
Map<String, Object> results = (Map<String, Object>)JSON.deserializeUntyped(result);
if(results.get('stations') != ''){
List<Object> lststations = (List<Object>)results.get('stations');
system.debug('@@@ lststations ==> ' + lststations.size());
if(lststations.size() > 0){
resset =(JsonParser)system.JSON.deserialize(result,JsonParser.class);
}
If there is stations are found then you will get the response as below. you capture these this things in your debug log.
{"stations":[{"stationName":"TIRUNELVELI TOWN","stationCode":"TYT"},{"stationName":"TIRUNELVELI","stationCode":"TEN"}]}
Please mark this as best answer if it helps to you!!!
Thanks,
Maharajan.C