How do I retrieve query parameters in a Spring Boot controller?

Question

I am developing a project using Spring Boot. I've a controller which accepts GET requests.

Currently I'm accepting requests to the following kind of URLs:

http://localhost:8888/user/data/002

but I want to accept requests using query parameters:

http://localhost:8888/user?data=002

Here's the code of my controller:

@RequestMapping(value="/data/{itemid}", method = RequestMethod.GET)
public @ResponseBody
item getitem(@PathVariable("itemid") String itemid) {   
    item i = itemDao.findOne(itemid);              
    String itemname = i.getItemname();
    String price = i.getPrice();
    return i;
}

Dosage

@RequestParam (good starting point: the official guide) – Barytes

> #32201941 – Fortress

Answer 1

Use @RequestParam

@RequestMapping(value="user", method = RequestMethod.GET)
public @ResponseBody Item getItem(@RequestParam("data") String itemid){

    Item i = itemDao.findOne(itemid);              
    String itemName = i.getItemName();
    String price = i.getPrice();
    return i;
}

Wold

then what is the URL of this method can you please tell ? What should i have to change – Dosage

sorry bro this URL is not working localhost:8888/user?data=001 I have enter this URL – Dosage

Remove value="/" from the request mapping annotation. Btw this is really poor design. If you're going to access an item for a user then the rest way would be user/items/{itemId}. – Wold

Using @RequestParam as public @ResponseBody item getitem(@RequestParam("data") String itemid){ requires data query parameter to be always present. Instead if you use it this way public @ResponseBody item getitem(@RequestParam Map<String, String> queryParameters){ , it makes data to be optional – Reider

@SampathSurineni it should be Map<String, String[]> queryParameters instead. – Billington

@samsri, or just use @RequestParam(name = "data", required = false) – Sonnnie

Latest looks like: If the method parameter is Map<String, String> or MultiValueMap<String, String> and a parameter name is not specified, then the map parameter is populated with all request parameter names and values. – Uppish

Answer 2

While the accepted answer by afraisse is absolutely correct in terms of using @RequestParam, I would further suggest to use an Optional<> as you cannot always ensure the right parameter is used. Also, if you need an Integer or Long just use that data type to avoid casting types later on in the DAO.

@RequestMapping(value="/data", method = RequestMethod.GET)
public @ResponseBody
Item getItem(@RequestParam("itemid") Optional<Integer> itemid) { 
    if( itemid.isPresent()){
         Item i = itemDao.findOne(itemid.get());              
         return i;
     } else ....
}

Stagecoach

where did you get Optional from? – Stylolite

@JoeyGough introduced in Java 8. docs.oracle.com/javase/8/docs/api/java/util/Optional.html – Stagecoach

It's a bad idea to put Optional in parameter. Don't use Optional in parameters. For this problem, you can use required = false. – Cf

@Cf why is it a bad idea to use Optional? – Showthrough

@hemanth5636, because you can have 3 possible values and not 2 ... (rules.sonarsource.com/java/RSPEC-3553) – Cf

But in this case Spring MVC will always populate it. So it will never be null. – Astragalus

Answer 3

To accept both @PathVariable and @RequestParam in the same /user endpoint:

@GetMapping(path = {"/user", "/user/{data}"})
public void user(@PathVariable(required=false,name="data") String data,
                 @RequestParam(required=false) Map<String,String> qparams) {
    qparams.forEach((a,b) -> {
        System.out.println(String.format("%s -> %s",a,b));
    }
  
    if (data != null) {
        System.out.println(data);
    }
}

Testing with curl:

• curl 'http://localhost:8080/user/books'
• curl 'http://localhost:8080/user?book=ofdreams&name=nietzsche'

Polak

what if you want to pass negatives, like &name!=nietzsche ? – Ineradicable

You can simply introduce another request parameter and put the unwanted name there :) – Bonilla

Answer 4

To accept both Path Variable and query Param in the same endpoint:

@RequestMapping(value = "/hello/{name}", method = RequestMethod.POST)
    public String sayHi(
            @PathVariable("name") String name, 
            @RequestBody Topic topic,
            //@RequestParam(required = false, name = "s") String s, 
            @RequestParam Map<String, String> req) {
        
        return "Hi "+name +" Topic : "+ topic+" RequestParams : "+req;
    }

URL looks like : http://localhost:8080/hello/testUser?city=Pune&Pin=411058&state=Maha

That

Answer 5

In Spring boot: 2.1.6, you can use like below:

    @GetMapping("/orders")
    @ApiOperation(value = "retrieve orders", response = OrderResponse.class, responseContainer = "List")
    public List<OrderResponse> getOrders(
            @RequestParam(value = "creationDateTimeFrom", required = true) String creationDateTimeFrom,
            @RequestParam(value = "creationDateTimeTo", required = true) String creationDateTimeTo,
            @RequestParam(value = "location_id", required = true) String location_id) {

        // TODO...

        return response;

@ApiOperation is an annotation that comes from Swagger api, It is used for documenting the apis.

Fend

required = true by default – Handicraft

Answer 6

I was interested in this as well and came across some examples on the Spring Boot site.

   // get with query string parameters e.g. /system/resource?id="rtze1cd2"&person="sam smith" 
// so below the first query parameter id is the variable and name is the variable
// id is shown below as a RequestParam
    @GetMapping("/system/resource")
    // this is for swagger docs
    @ApiOperation(value = "Get the resource identified by id and person")
    ResponseEntity<?> getSomeResourceWithParameters(@RequestParam String id, @RequestParam("person") String name) {

        InterestingResource resource = getMyInterestingResourc(id, name);
        logger.info("Request to get an id of "+id+" with a name of person: "+name);

        return new ResponseEntity<Object>(resource, HttpStatus.OK);
    }

See here also

Joniejonina

Answer 7

When using the @GetMapping annotation, you typically use @RequestParam in the request instead of @RequestBody. If you want to use @RequestBody, you should use the @PostMapping annotation in the API method.

Matusow