Handling Multiple Query Parameters in Jersey

Question

In the web service I\'m working on, I need to implement a URI with query parameters which look like /stats?store=A&store=B&item=C&item=D

To

Answer 1

List<String> items=ui.getQueryParameters().get("item");

where ui is declared as a member in the rest resource like so :

@Context UriInfo ui;

the downside is that it doesn't appear in the methods arguments at all.

Answer 2

Some libs like axios js use the square brackets notation when sending a multi-value param request: /stats?store[]=A&store[]=B&item[]=C&item[]=D

To handle all cases (with or without square brackets) you can add another param like this:

public String methodImCalling(
  @QueryParam(value = "store") final List<String> store, 
  @QueryParam(value = "store[]") final List<String> storeWithBrackets, 
  @QueryParam(value = "item") final List<String> item,
  @QueryParam(value = "item[]") final List<String> itemWithBrackets) {
...
}

Inspecting each of the arguments checking for null.

Answer 3

If you change the type of your item method parameter from String to a collection such as List<String>, you should get a collection that holds all the values you are looking for.

@GET
@Path("/foo")
@Produces("text/plain")
public String methodImCalling(@DefaultValue("All") 
                              @QueryParam(value = "item") 
                              final List<String> item) {
   return "values are " + item;
}

The JAX-RS specification (section 3.2) says the following regarding the @QueryParam annotation:

The following types are supported:

1. Primitive Types
2. Types that have a constructor that accepts a single String argument.
3. Types that have a static method named valueOf with a single String argument.
4. List<T>, Set<T>, or SortedSet<T> where T satisfies 2 or 3 above.