Java Reference
In-Depth Information
47. @ModelAttribute("authorList")
48. public List<Author> populateAuthorList() {
49. AuthorService authorService = new AuthorService();
50. return authorService.getAuthorList();
51. }
52.
53. @RequestMapping(method = RequestMethod.POST)
54. public String processSubmit(@ModelAttribute("book") Book book, BindingResult result,
SessionStatus status) {
55. BookService bookService = new BookService();
56. bookService.createBook(book);
57. return "redirect:/list_book.html";
58. }
59. }
Line 22
: The
AddBookController
class is annotated with
@RequestMapping("/addBook.html")
, which means that all the methods in
this class will handle the request for the URL
"/ addBook.html"
.
Line 24
: The initialization for binding is done by annotating the method name
with
@RequestMapping(method=RequestMethod.GET)
.
Line 25
:
initForm()
handles the
GET
request type and shows the add new
book form.
Line 28
:
initForm()
also adds a new instance to the model map so that the new
instance can be associated with the form.
Line 32
: Binding is defined by annotating the method name with
@InitBinder
.
Annotating controller methods with
@InitBinder
allows configuring the web data
binding directly within the controller class.
@InitBinder
identifies methods that
initialize the
WebDataBinder
that is used to populate the command and form object
arguments of annotated handler methods. Such init-binder methods support all
arguments that
@RequestMapping
supports, except for command/form objects and
the corresponding validation result objects. Init-binder methods that are declared
must not have a return value. Thus, they are usually declared as void.
Line 33
: Typical arguments include
WebDataBinder
in combination with
WebRequest
or
java.util.Locale
, allowing code to register context-specific editors.
Data binding is configured using the
WebDataBinder
class.
WebDataBinder
is
a special
DataBinder
for data binding from web request parameters to
JavaBean objects.
Spring injects an instance of this class into any controller method that has been
annotated with
@InitBinder
. This object is then used to define the data binding
rules for the controller.
WebRequest
allows for generic request parameter access as well as
request/session attribute access without ties to the native Servlet API.
Line 34
:
setDisallowedFields()
registers the fields that are not allowed
for binding.
