Controller Layer

In Spring MVC, the controller layer is the top layer of the architecture that is used to handle web requests. Then depending on the type of request, it passed it to corresponding layers.

Annotations used:

@Controller – This annotation marks that the particular class serves the role of a controller.
@GetMapping – This annotation marks the mapping of HTTP GET requests onto specific handler methods.
@PostMapping – This annotation marks the mapping of HTTP POST requests onto specific method handlers.

Java

import com.example.testing_001.model.Course;
import com.example.testing_001.service.CourseService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
 
import java.util.List;
 
@Controller
public class CourseController {
 
    @Autowired
    private CourseService courseService;
 
    @GetMapping("/")
    public String viewHomePage(Model model) {
        return findPaginated(1, "courseName", "asc", model);
    }
 
    @GetMapping("/add")
    public String showNewCourseForm(Model model) {
        Course Course = new Course();
        model.addAttribute("course", Course);
        return "new_course";
    }
 
    @PostMapping("/save")
    public String saveCourse(@ModelAttribute("course") Course course) {
        // save Course to database
        courseService.saveCourse(course);
        return "redirect:/";
    }
 
    @GetMapping("/update/{id}")
    public String showFormForUpdate(@PathVariable( value = "id") long id, Model model) {
 
        Course course = courseService.getCourseById(id);
        model.addAttribute("course", course);
        return "update_course";
    }
 
    @GetMapping("/delete/{id}")
    public String deleteCourse(@PathVariable (value = "id") long id) {
 
        this.courseService.deleteCourseById(id);
        return "redirect:/";
    }
 
 
    @GetMapping("/page/{pageNo}")
    public String findPaginated(@PathVariable (value = "pageNo") int pageNo,
                                @RequestParam("sortField") String sortField,
                                @RequestParam("sortDir") String sortDir,
                                Model model) {
        int pageSize = 5;
 
        Page<Course> page = courseService.findPaginated(pageNo, pageSize, sortField, sortDir);
        List<Course> listCourses = page.getContent();
 
        model.addAttribute("currentPage", pageNo);
        model.addAttribute("totalPages", page.getTotalPages());
        model.addAttribute("totalItems", page.getTotalElements());
 
        model.addAttribute("sortField", sortField);
        model.addAttribute("sortDir", sortDir);
        model.addAttribute("reverseSortDir", sortDir.equals("asc") ? "desc" : "asc");
 
        model.addAttribute("listCourses", listCourses);
        return "index";
    }
}

TRY: Change the GET mapping for course update and delete course to PUT mapping and DELETE mapping respectively. It is considered best practice to use mappings based on the functionality of the api.

Spring MVC CRUD with Example

CRUD stands for Create, Read/Retrieve, Update, and Delete. These are the four basic operations to create any type of project. Spring MVC is a Web MVC Framework for building web applications. It is a spring module same as Spring boot, spring-security, etc. The term MVC stands for Model-View-Controller architecture. In this article, we will be building a simple course-tracking CRUD application that will be focused on the Spring MVC module.

Controller Layer

Java

Spring MVC CRUD with Example

Similar Reads

Contact Us