Springboot

Controllers

A key difference between a traditional MVC controller and the RESTful web service controller from Springboot is the way that the HTTP response body is created.

@GetMapping("/greeting")
public Greeting greeting(@RequestParam(value = "name", defaultValue = "World") String name) {
  return new Greeting(counter.incrementAndGet(), String.format(template, name));
}

• Rather than relying on a View technology to perform server-side rendering of the greeting data to HTML, this RESTful web service controller populates and returns a Greeting object. The object data will be written directly to the HTTP response as JSON. To do this, the Greeting object must be converted to JSON
  • Spring’s out-of-the-box HTTP message converter support allows us to do this. This works out of the box because Jackson 2 (the Java JSON package) is in the classpath

@RestController

The @RestController annotation marks the class as a controller where every method returns a domain object instead of a view.

• it is shorthand for including both @Controller and @ResponseBody.