How can I pass an object as a query param in URI line?

Question

Could you please help me and explain how should I pass an author value?

@GetMapping(value = "/search")
    public ResponseEntity<List<Book>> searchBooksByTitleAndAuthor(
            @RequestParam(value = "title", required = false) final String title,
            @RequestParam(value = "author", required = false) final Author author) {
        HttpStatus httpStatus = HttpStatus.OK;
        List<Book> books = null;
        if (title == null && author == null) {
            log.info("Empty request");
            httpStatus = HttpStatus.BAD_REQUEST;
        } else if (title == null || author == null) {
            books = bookService.getBooksByTitleOrAuthor(title, author);
        } else {
            Optional<Book> book = bookService.getBookByTitleAndAuthor(title, author);
            if (book.isPresent()) {
                books = Arrays.asList(book.get());
            }
        }
        if (books == null) {
            return new ResponseEntity<>(httpStatus);
        } else {
            return new ResponseEntity<>(books, httpStatus);
        }
    }

And Author class that looks like:

@Entity
@NoArgsConstructor
@AllArgsConstructor
@Getter
@EqualsAndHashCode
@ToString
public final class Author {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long id;

    private String name;

    private LocalDate dateOfBirth;

    private String bio;
}

Is it a good approach to use author or @RequestParam instead of request body in this situation? I've thought about requesting only String that is authors' name but it will affect service's methods.

Couldn't you use the author ID instead of the full author? – Daniele May 19 '18 at 20:29 — Daniele, May 19 '18 at 20:29

score 2 · Accepted Answer · answered May 19 '18 at 22:02

According to https://lankydanblog.com/2017/03/11/passing-data-transfer-objects-with-get-in-spring-boot/ , ... you can (after you set some conversion annotations on your author.dateOfBirth):

Use @RequestParam on a String parameter (and let your controller/someone do the conversion):

    ..., @RequestParam(value = "author", required = false) final String author) { 

     ...final Author author = new ObjectMapper().setDateFormat(simpleDateFormat)
                             .readValue(author, Author.class);

In this case you would request like:

http://localhost:8080/myApp/search?title=foo&author={"id"="1",...}

alternatively: Omit @RequestParam, but pass the object (and let spring care for conversion):

...(@RequestParam(value = "title", required = false) final String title,
     final Author author)

and request like:

http://localhost:8080/myApp/search?title=foo&id=1&name=Donald E. Knuth&...

How can I pass an object as a query param in URI line?

1 Answers1