Problems Parsing JSON Responses with Apex
December 28th, 2009
A couple of weeks ago I wrote an article and small demo of a REST web service call returning XML. It was my intention to do the same demo using JSON. However, I ran into a small sang; I couldn’t get the Apex JSONObject to work. I worked on the code for most of the week before Christmas but couldn’t beat it into submission. I may be a tad dense but I looked through the code, made a couple of changes but couldn’t get the thing to work.
I was able to parse some simple JSON objects but complex objects did not want to cooperate. I received a couple of responses from Twitter and not many people have had much luck using the JSONObject with complex responses.
I started by downloading the JSONObject class from here and installed it into my Developer org. Then to use the Google Maps API Services I signed up for an API key and then took a look at their geocoding docs for JSON.
I started off by trying to parse the JSON response from their example URL. I executed the following code anonymously:
1 2 3 4 5 6 7 8 9 10 | JSONObject jsonObject;
HttpRequest req = new HttpRequest();
Http http = new Http();
req.setMethod('GET');
String url = 'http://maps.google.com/maps/geo?q=1600+Amphitheatre+Parkway,+Mountain+View,+CA&output=json&sensor=false&key=MY_API_KEY';
req.setEndpoint(url);
HTTPResponse resp = http.send(req);
JSONObject j = new JSONObject( resp.getBody() ); |
This produced the error:
System.TypeException: Invalid integer: -122.0843700
The JSON parser was supposed to return a string when it was not able to parse a value but it appeared to be choking on non-integers. I added the following to line 1374 before the value was returned:
new value( Integer.valueof(s) );
That at least seemed to fix the parsing problem, but now line 1335 was throwing a new error:
“Missing value”
I gave up hope using the Google Maps geocoding and thought I’d try a different approach. Yahoo! Web Services has really good JSON service so I thought I would try and use this JSON response. My code executed successfully and I didn’t receive any errors parsing the JSON response. My only problem was that I couldn’t really debug it much as I received the following message due to all of the parsing of the values:
*********** MAXIMUM DEBUG LOG SIZE REACHED ***********
So now I’m kind of stuck. Ron Hess offered to help out and take a look. I’m sure other people would like to use the JSONObject Apex class!
Categories: Apex, Code Sample, Salesforce
Hi Jeff, i have a few ideas but wanted to point out that there is a geocoding project in code share, look for the google earth project. For the json response, did you capture the JSON string that we can use to debug the parser?
Also, if you max out the debug log, you can turn off profiling and database info , then add system debug statements to see what is going on in the class
i found the JSON, somehow the parser thinks this is an array of int
“coordinates”: [ -122.0841430, 37.4219720, 0 ]
here is the fix, worked for my simple test
at line 1374 replace the try {} …
with this
try {
Integer si = Integer.valueof(s);
return new value( si );
} catch (System.TypeException e) {
try {
return new value( Double.valueof(s) );
} catch (System.TypeException g) {
// fall thru
}
}
Hey,
cant you use XML parsing technique here?
[...] Since posting this Jeff Douglas has written about JSON in SalesForce [...]
Hey Jeff how are you, Im very new to the blog’s and I dnt evn know hw to use or register the blogs, but I found very much interesting stuff in here and u r helping people a lot, since Im getting in to SFDC I would definitely need ur help and ur guidance…..please respond my comment so that I cn be down here eaisly without searching in google…
cheers
Sandy