[FIXED] Table is not loaded using Spring boot

Issue

i am creating simple spring boot application project. i have create two various controller those are student and course controller and Index controller is Index controller is a Main Page .when i ran the project index is loaded sucessfully.when i click the course link success visit to course page but course tables is not loaded and course page as link addnewcourse when i click that it will redirect to HTTP Status 404 – Not Found. i don't that what i was happing i attached the full source code on github link here https://github.com/raguram1986/SpringSecuritys i attached the screenshot image below the folder structure.

Course Controller

 @Controller
    @RequestMapping("/Course")
    
    public class CourseController {
        
         @Autowired
            private CourseService service;
    
           @GetMapping("/")
            public String viewHomePage(Model model) {
                List<Course> listcourse = service.listAll();
                model.addAttribute("listcourse", listcourse);
                System.out.print("Get / "); 
                return "course";
            }
    
            @GetMapping("/addcourse")
            public String add(Model model) {
                List<Course> listcourse = service.listAll();
                model.addAttribute("listcourse", listcourse);
                model.addAttribute("course", new Course());
                return "addcourse";
            }
            
    
            @RequestMapping(value = "/save", method = RequestMethod.POST)
            public String saveCourse(@ModelAttribute("course") Course course) {
                service.save(course);
                return "redirect:/";
            }
    
            @RequestMapping("/edit/{id}")
            public ModelAndView showEditCoursePage(@PathVariable(name = "id") int id) {
                ModelAndView mav = new ModelAndView("addcourse");
                Course course = service.get(id);
                mav.addObject("course", course);
                return mav;
                
            }
            @RequestMapping("/delete/{id}")
            public String deleteCoursePage(@PathVariable(name = "id") int id) {
                service.delete(id);
                return "redirect:/";
            }
    }

Domain

@Entity
public class Course {
    
    @Id
    @GeneratedValue(strategy= GenerationType.IDENTITY)
    private Long id;
    private String coursename;
    private int duration;

    public Course()
    {       
        
    }
 
    public Course(Long id, String coursename, int duration) {
        
        this.id = id;
        this.coursename = coursename;
        this.duration = duration;
    }
    

    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getCoursename() {
        return coursename;
    }
    public void setCoursename(String coursename) {
        this.coursename = coursename;
    }
    public int getDuration() {
        return duration;
    }
    public void setDuration(int duration) {
        this.duration = duration;
    }


    @Override
    public String toString() {
        return "Course [id=" + id + ", coursename=" + coursename + ", duration=" + duration + "]";
    }
  

}

Repository

@Repository
public interface CourseRepository extends JpaRepository<Course, Long>{

}

Service

@Service
public class CourseService 
{
    @Autowired
    private CourseRepository repo;
    
    public List<Course> listAll() {
        return repo.findAll();
    }
     
    public void save(Course course) {
        repo.save(course);
    }
     
    public Course get(long id) {
        return repo.findById(id).get();
    }
     
    public void delete(long id) {
        repo.deleteById(id);
    }

}

Course.html

<div>
    <h2 >Course Creation</h2>
    <tr>
        <div align = "left" >
           
             <h3><a  th:href="@{'/addcourse'}">Add new</a></h3>  
           
        </div>
    
    </tr>

    <div class="col-sm-8" align = "center">
    <div class="panel-body" align = "center" >
                 
                 
  <table class="table">
  <thead class="thead-dark">
    <tr>
            <th>Course ID</th>
            <th>Course Name</th>
            <th>Duration</th>
             <th>edit</th>
             <th>delete</th>
    </tr>
  </thead>
  <tbody>
      <tr  th:each="course : ${listcourse}">
        <td th:text="${course.id}">Course ID</td>
        <td th:text="${course.coursename}">Course Name</td>
        <td th:text="${course.duration}">Duration</td>

        <td>
            <a th:href="@{'/edit/' + ${course.id}}">Edit</a>
        </td>                               
        <td>
            <a th:href="@{'/delete/' + ${course.id}}">Delete</a>
        </td>           
        </tr> 
   
  </tbody>
</table>

                    
                 </div>

            </div> 

    </tr>

    </tbody>
    </table>
    <div>

Solution

You have @RequestMapping("/Course") annotation on CourseController and in Course.html you trying to make request to /addcourse (i guess, please check in your browser development tool) but you need to make request to /Course/addcourse endpoint because of annotation on controller class. So u need to change <h3><a th:href="@{'/addcourse'}">Add new</a></h3> to <h3><a th:href="@{'/Course/addcourse'}">Add new</a></h3>

Answered By - ARManakhov