How to pass List or String array to getForObject with Spring RestTemplate

Question

I am developing some restful services with Spring. I have trouble with passing/getting string array or large string as parameters to my service controller. My code examples are like below;

Controller:

@RequestMapping(value="/getLocationInformations/{pointList}", method=RequestMethod.GET)
@ResponseBody
public LocationInfoObject getLocationInformations(@PathVariable("pointList") String pointList)
{
    // code block
}

Sample point list:

String pointList = "37.0433;35.2663,37.0431;35.2663,37.0429;35.2664,37.0428;35.2664,37.0426;35.2665,37.0424;35.2667,37.0422;35.2669,37.042;35.2671,37.0419;35.2673,37.0417;35.2674,37.0415;35.2674,37.0412;35.2672,37.0408;35.267,37.04;35.2667,37.0396;35.2665,37.0391;35.2663,37.0388;35.2662,37.0384;35.266,37.0381;35.2659,37.0379;35.2658,37.0377;35.2657,37.0404;35.2668,37.0377;35.2656,37.0378;35.2652,37.0378;35.2652,37.0381;35.2646,37.0382;35.264,37.0381;35.2635,37.038;35.263,37.0379;35.2627,37.0378;35.2626,37.0376;35.2626,37.0372;35.2627,37.0367;35.2628,37.0363;35.2628,37.036;35.2629,37.0357;35.2629,37.0356;35.2628,37.0356;35.2628,37.0355;35.2626";

Web service client code:

Map<String, String> vars = new HashMap<String, String>();
vars.put("pointList", pointList);

String apiUrl = "http://api.website.com/service/getLocationInformations/{pointList}";

RestTemplate restTemplate = new RestTemplate();
LocationInfoObject result = restTemplate.getForObject(apiUrl, LocationInfoObject.class, vars);

When I run client side application, it throws a HttpClientErrorException: 400 Bad Request, I think long location information string causes to this problem. So, how can I solve this issue? Or is it possible posting long string value as parameter to web service?

Thx all

Answer 1

List or other type of objects can post with RestTemplate's postForObject method. My solution is like below:

controller:

@RequestMapping(value="/getLocationInformations", method=RequestMethod.POST)
@ResponseBody
public LocationInfoObject getLocationInformations(@RequestBody RequestObject requestObject)
{
    // code block
}

Create a request object for posting to service:

public class RequestObject implements Serializable
{
    public List<Point> pointList    = null;
}

public class Point 
{
    public Float latitude = null;
    public Float longitude = null;
}

Create a response object to get values from service:

public class ResponseObject implements Serializable
{
    public Boolean success                  = false;
    public Integer statusCode               = null;
    public String status                    = null;
    public LocationInfoObject locationInfo  = null;
}

Post point list with request object and get response object from service:

String apiUrl = "http://api.website.com/service/getLocationInformations";
RequestObject requestObject = new RequestObject();
// create pointList and add to requestObject
requestObject.setPointList(pointList);

RestTemplate restTemplate = new RestTemplate();
ResponseObject response = restTemplate.postForObject(apiUrl, requestObject, ResponseObject.class);

// response.getSuccess(), response.getStatusCode(), response.getStatus(), response.getLocationInfo() can be used

Answer 2

The question is related to GET resource, not POST. Because of that I think that "accepted answer" is not the correct one.

So for other googlers like me that finds this, Ill add what helps me:

GET resources can receive a string list via @PathVariable or @RequestParam and even correctly bind it to a List<String> if you do pass the list separated by ,.

Your API can be:

@RequestMapping(value="/getLocationInformations/{pointList}", method=RequestMethod.GET)
@ResponseBody
public LocationInfoObject getLocationInformations(@PathVariable("pointList") List<String> pointList) {
    // code block
}

And your call would be:

List<String> listOfPoints = ...;
String points = String.join(",", listOfPoints);

String apiUrl = "http://api.website.com/service/getLocationInformations/{pointList}";
LocationInfoObject result = restTemplate.getForObject(apiUrl, LocationInfoObject.class, points);

Note that you must send lists to API using , as separator, otherwise the API cannot recognize it as a list. Also you cannot just add your list directly as a parameter, because depending on how it's mashalled the generated string may not be compatible.