java - How to replace @Controller by @RestController?

Question

Here is my TeacherController :

@Controller
@RequestMapping("/teacherController")
public class TeacherController {
private static final String TEACHER_MODEL = "teacher";
@Autowired
TeacherService teacherService;


@RequestMapping("check")
public ModelAndView index() {
    ModelAndView modelAndView = new ModelAndView();
    modelAndView.addObject("teachers", teacherService.getAll());
    modelAndView.setViewName("/teacherViews/teachersPage");
    return modelAndView;
}

And here page where I print my table :

<table  class="table table-dark" border="1" width="100%" cellpadding="5">
<thead>
<tr>
    <th>Teacher ID</th>
    <th>Teacher Name</th>
    <th>Teacher Position</th>
</tr>
</thead>
<tbody id="teacherBody">
<tr th:each="teacher : ${teachers}">
    <td th:text="${teacher.teacherId}" />
    <td th:text="${teacher.teacherName}" />
    <td th:text="${teacher.position}" />
</tr>
</tbody>

And all that I wrote above I need to rewrite using RestController and AJAX. I want that table data loads with loading page automatically, as I understand, It can works with js.

So, my problem is that I need to rewrite my Controller to RestController with AJAX but I don't understand how to do it.

Thanks in advance for your help!!!

Answer 1

Difference between @Controller and @Rest Controller

@Controller

The @Controller annotation has been part of the framework for a very long time.@Controller annotation designates that the annotated class is a controller. It is a specialization of @Controller and is autodetected through classpath scanning. It is typically utilized in amalgamation with annotated handler methods predicated on the @RequestMapping annotation.

For example,

@Controller
@RequestMapping("users")
public class HomeController {

    @GetMapping(produces = "application/json")
    public @ResponseBody User getAllUsers() {
        return findAllUsers();
    }
}

The request handling method is annotated with @ResponseBody. This annotation enables automatic serialization of the return object into the HttpResponse.

@RestController

The @RestController annotation was introduced in Spring 4.0 to simplify the engenderment of RESTful web services. It's an convenience annotation that combines @Controller and @ResponseBody

For example,

@RestController
@RequestMapping("users")
public class HomeController {

    @GetMapping(produces = "application/json")
    public Book getAllUsers() {
        return findAllUsers();
    }
}

The controller is annotated with the @RestController annotation, consequently the @ResponseBody isn't required. Every request handling method of the controller class automatically serializes return objects into HttpResponse. Link

After conversion

RestController

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api/v1")
public class TeacherController {

    @Autowired
    TeacherService teacherService;

    @GetMapping("/teacher")
    public List<Teacher> fetchAllTeacher() {
        return teacherService.getAll();
    }
}

HTML

<table id="table-content" border='1'>
<tr>
    <th>Teacher ID</th>
     <th>Teacher Name</th>
    <th>Teacher Position</th>
</tr>

Javascript(Not tested)

var service = 'http://localhost/api/v1/';

$(document).ready(function(){

    jQuery.support.cors = true;

    $.ajax(
    {
        type: "GET",
        url: service + '/teacher/',
        data: "{}",
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        cache: false,
        success: function (data) {
            
        var trHTML = '';
                
        $.each(data, function (i, item) {
            
            trHTML += '<tr><td>' + data.Teacher[i].Name + '</td><td>' + data.Teacher[i].Position + '</td></tr>';
        });
        
        $('#table-content').append(trHTML);
        
        },
        
        error: function (msg) {
            
            alert(msg.responseText);
        }
    });
})