10.4. Class Level Controller Annotations

10.4.1. Controller Classes - Video

Note

The starter code for this video is found in the forms branch of the hello-spring-demo repo. The final code presented in this video is found on the class-annotations branch. As always, code along to the videos on your own hello-spring project.

Have you been tracking your app progress in your own git branches? Saving your progress in branches for each video tutorial means you can always go back to a certain spot in the app development. We will be returning to the forms branch in the next lesson so track your class-annotations in a new branch with git checkout -b <branch-name>.

10.4.2. Controller Classes - Text

Once you have written several controller methods within a class, you may notice some similar behavior across handlers. This is an opportunity to DRY your code. Some of the annotations we use at the method level can also be used on whole controller classes.

We mention this earlier. If all of the methods in a controller class begin with the same root path, @RequestMapping can be added above the class.

@Controller
@RequestMapping(value="hello")
public class HelloController {

   // responds to /hello
   @GetMapping("")
    @ResponseBody
    public String hello() {
     return "Hello";
    }

   // responds to /hello/goodbye
   @GetMapping("goodbye")
    @ResponseBody
    public String helloGoodbye() {
     return "Hello, Goodbye";
    }
}

Note that we use @RequestMapping on the class. @GetMapping and @PostMapping cannot be applied at the class level.

In a related fashion, if you find that each of your methods in a controller class use @ResponseBody to return plain text, this annotation may be added at the top of the class, rather than at each method declaration.

10.4.3. Check Your Understanding

Question

True/False: No one controller method can handle several request types.

  1. True

  2. False

Question

We want the method hello to take another parameter, @RequestParam String friend, that will add a friend’s name to the returned greeting. The use should also be able to enter this name via a text field. What needs to be added to the form?

  1. Another input tag with a friend attribute.

  2. Another input tag with a name attribute.

  3. Another form tag with a method attribute.

  4. Another submit tag with a friend value.