What are the differences in these 2 controllers?

[Andrea Nobili]

Hello to all,

I am studing the Spring MVC showcase example downloaded from the STS dashboard.

I have a basic question for you:

In my home.jsp view I have two links, something like that:

<ul> <li> <a id="simpleLink" class="textLink" href="<c:url value="/simple" />">GET /simple</a> </li> <li> <a id="simpleRevisited" class="textLink" href="<c:url value="/simple/revisited" />">GET /simple/revisited</a> </li>

So, in this example the first one is handled by a controller class named SimpleController and the second one is handled by a controller class named SimpleControllerRevisited

This is the code of SimpleController class:

package org.springframework.samples.mvc.simple;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class SimpleController {

	@RequestMapping("/simple")
	public @ResponseBody String simple() {
		return "Hello world!";
	}
	
}

As you can see the simple() method is annoted by @RequestMapping("/simple") annotation so it mean that this method handles request towards "/simple" folder. This method return a String to the caller and this string is encapsulated into the BODY section of the HTTP Response...ok it is very simple !!

Now this is the code of SimpleControllerRevisited

package org.springframework.samples.mvc.simple;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class SimpleControllerRevisited {

	@RequestMapping(value="/simple/revisited", method=RequestMethod.GET, headers="Accept=text/plain")
	public @ResponseBody String simple() {
		return "Hello world revisited!";
	}

}

It is very similar to the previus SimpleController() method. It handles request towards "/simple/revisited" folder and return a string into the BODY of the HTTP Response

what is the difference between these two methods?

When I do:
method=RequestMethod.GET I'm specifying that the HTTP Request type is a GET...but is it not the default HTTP Request? Also in the other method is a GET although it is not explicitly specified? Or what?

What do exactly the: headers="Accept=text/plain" parameter of the @RequestMapping annotation?

thank you very much
Andrea

[Mark Spritzler]

OK, the first one will also map tp POST, PUT and DELETE RequestMethodTypes. The second will only allow GET requests. For the second one the accept portion means the Request Header must have headers="Accept=text/plain" Otherwise that method will not be called regardless of URL or RequestMethod type.

Mark