Crud Operation Examples

CRUD (CREATE,READ,UPDATE,DELETE)operation spring program to find student by id with get and post request

Example-1:

Here’s an example Spring program that demonstrates how to perform CRUD operations and implement GET and POST requests to find a student by their ID.

• First, let’s define the Student class that represents a student and their details.
• First, let’s define the Student class that represents a student and their details.

  public class Student {
    private int id;
    private String name;
    private String email;
    // getters and setters
  }
  

• Next, let’s create a StudentController class that handles the requests.

  @RestController
  @RequestMapping("/students")
  public class StudentController {
  
    private Map<Integer, Student> students = new HashMap<>(); // a collection to store students
  
    // POST request to add a new student
    @PostMapping("/add")
    public ResponseEntity<Student> addStudent(@RequestBody Student student) {
        students.put(student.getId(), student);
        return ResponseEntity.ok(student);
    }
  
    // GET request to find a student by ID
    @GetMapping("/{id}")
    public ResponseEntity<Student> getStudentById(@PathVariable int id) {
        if (students.containsKey(id)) {
            return ResponseEntity.ok(students.get(id));
        }
        return ResponseEntity.notFound().build();
    }
  }
  

• In this class, we have defined two methods - addStudent and getStudentById.
• The addStudent method handles a POST request to add a new student to the collection. It takes in a Student object in the request body, adds it to the students collection, and returns the same student object with an HTTP status code of 200 (OK).

• The getStudentById method handles a GET request to find a student by their ID. It takes in the id of the student in the path variable, checks if the students collection contains a student with that ID, and returns the student object with an HTTP status code of 200 (OK) if found, or a 404 (Not Found) status code if not found.

• Finally, let’s define the main class that runs the Spring application.

  @SpringBootApplication
  public class StudentApplication {
  
    public static void main(String[] args) {
        SpringApplication.run(StudentApplication.class, args);
    }
  }
  

• That’s it! You can now run the application and test it out using a REST client or a web browser. Here are a few sample requests:

• To add a new student: ``` java POST http://localhost:8080/students/add Content-Type: application/json

{ “id”: 1, “name”: “John Doe”, “email”: “johndoe@example.com” }

* To find a student by ID:
``` java
GET http://localhost:8080/students/1

• This should return the following response:

  {
    "id": 1,
    "name": "John Doe",
    "email": "johndoe@example.com"
  }