REST API

01.07.2026 | Muallif: Jaxongir a.k.a | Kategoriya: Spring Boot | 20 daqiqa o'qish

Bu bo‘limda Spring Boot’da birinchi haqiqiy REST API yozishni o‘rganamiz. Bu mavzu ichida @RestController, @RequestMapping, @GetMapping, @PostMapping, @PutMapping, @DeleteMapping, @PathVariable, @RequestParam, @RequestBody, ResponseEntity va HTTP status codes bor.

1. REST API nima?

REST API - frontend, mobile app yoki boshqa servis backend bilan gaplashishi uchun ishlatiladigan HTTP API.

Masalan, mobil app backenddan userlar ro‘yxatini so‘raydi:

GET /users

Backend javob qaytaradi:

[
  {
    "id": 1,
    "name": "Ali"
  },
  {
    "id": 2,
    "name": "Vali"
  }
]

Oddiy qilib:

REST API - client va server o‘rtasidagi kelishilgan HTTP muloqot.

2. REST API qayerda ishlatiladi?

Masalan:

Android app → Spring Boot API
iOS app     → Spring Boot API
React app   → Spring Boot API
Telegram bot → Spring Boot API
Boshqa microservice → Spring Boot API

Backend odatda JSON qaytaradi.

3. HTTP methodlar

REST API’da eng ko‘p ishlatiladigan methodlar:

Method	Vazifasi	Misol
`GET`	Ma’lumot olish	Userlarni olish
`POST`	Yangi ma’lumot yaratish	Yangi user qo‘shish
`PUT`	Ma’lumotni to‘liq yangilash	Userni update qilish
`PATCH`	Qisman yangilash	Faqat phone numberni update qilish
`DELETE`	Ma’lumot o‘chirish	Userni o‘chirish

4. Birinchi controller

Spring Boot’da REST API yozish uchun @RestController ishlatiladi.

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String hello() {
        return "Salom Spring Boot";
    }
}

Brauzerda ochamiz:

http://localhost:8080/hello

Natija:

Salom Spring Boot

5. `@RestController` nima?

@RestController - bu class REST API controller ekanini bildiradi.

Ya’ni:

@RestController
public class UserController {
}

Spring bu classni HTTP request qabul qiladigan controller sifatida ko‘radi.

Muhim jihati:

@RestController methoddan qaytgan qiymatni avtomatik HTTP response body qilib beradi.

Masalan:

@GetMapping("/name")
public String name() {
    return "Ali";
}

Javob body:

Ali

6. `@RequestMapping` nima?

@RequestMapping umumiy path berish uchun ishlatiladi.

Masalan:

@RestController
@RequestMapping("/users")
public class UserController {
}

Endi shu controller ichidagi hamma endpoint /users bilan boshlanadi.

@GetMapping
public String getUsers() {
    return "Users list";
}

Full path:

GET /users

7. `@GetMapping`

GET - ma’lumot olish uchun.

@RestController
@RequestMapping("/users")
public class UserController {

    @GetMapping
    public String getUsers() {
        return "Userlar ro'yxati";
    }
}

Request:

GET /users

Response:

Userlar ro'yxati

8. @PostMapping

POST - yangi ma’lumot yaratish uchun.

@PostMapping
public String createUser() {
    return "User yaratildi";
}

Request:

POST /users

Response:

User yaratildi

Lekin real loyihada POST odatda body bilan keladi.

9. `@PutMapping`

PUT - mavjud ma’lumotni yangilash uchun.

@PutMapping("/{id}")
public String updateUser(@PathVariable Long id) {
    return "User yangilandi: " + id;
}

Request:

PUT /users/5

Response:

User yangilandi: 5

10. `@DeleteMapping`

DELETE - ma’lumotni o‘chirish uchun.

@DeleteMapping("/{id}")
public String deleteUser(@PathVariable Long id) {
    return "User o'chirildi: " + id;
}

Request:

DELETE /users/5

Response:

User o'chirildi: 5

11. To‘liq CRUD endpointlar

@RestController
@RequestMapping("/users")
public class UserController {

    @GetMapping
    public String getUsers() {
        return "Barcha userlar";
    }

    @GetMapping("/{id}")
    public String getUserById(@PathVariable Long id) {
        return "User ID: " + id;
    }

    @PostMapping
    public String createUser() {
        return "User yaratildi";
    }

    @PutMapping("/{id}")
    public String updateUser(@PathVariable Long id) {
        return "User yangilandi: " + id;
    }

    @DeleteMapping("/{id}")
    public String deleteUser(@PathVariable Long id) {
        return "User o'chirildi: " + id;
    }
}

Endpointlar:

GET    /users
GET    /users/1
POST   /users
PUT    /users/1
DELETE /users/1

12. `@PathVariable` nima?

@PathVariable - URL ichidagi qiymatni olish uchun ishlatiladi.

Masalan:

GET /users/10

Bu yerda 10 - path variable.

Kod:

@GetMapping("/{id}")
public String getUser(@PathVariable Long id) {
    return "User ID: " + id;
}

Natija:

User ID: 10

`@PathVariable` nomi boshqacha bo‘lsa

@GetMapping("/{userId}")
public String getUser(@PathVariable Long userId) {
    return "User ID: " + userId;
}

Yoki aniq ko‘rsatish mumkin:

@GetMapping("/{id}")
public String getUser(@PathVariable("id") Long userId) {
    return "User ID: " + userId;
}

13. `@RequestParam` nima?

@RequestParam - URL query parameter olish uchun ishlatiladi.

Masalan:

GET /users?name=Ali

Kod:

@GetMapping("/search")
public String searchUser(@RequestParam String name) {
    return "Qidirilgan user: " + name;
}

Request:

GET /users/search?name=Ali

Response:

Qidirilgan user: Ali

Bir nechta `@RequestParam`

GET /users/search?name=Ali&age=25

@GetMapping("/search")
public String searchUser(
        @RequestParam String name,
        @RequestParam Integer age
) {
    return name + " - " + age;
}

Optional `@RequestParam`

Agar parameter kelmasa ham xato bermasin desak:

@GetMapping("/search")
public String searchUser(
        @RequestParam(required = false) String name
) {
    return "Name: " + name;
}

Default qiymat berish:

@GetMapping("/search")
public String searchUser(
        @RequestParam(defaultValue = "unknown") String name
) {
    return "Name: " + name;
}

14. `@PathVariable` vs `@RequestParam`

Turi	Qayerdan oladi?	Misol
`@PathVariable`	URL path ichidan	`/users/5`
`@RequestParam`	Query parameterdan	`/users?name=Ali`

Qachon qaysi biri?

/users/5             → aniq bitta user olish → @PathVariable
/users?name=Ali      → filter/search qilish → @RequestParam
/users?page=1&size=20 → pagination → @RequestParam

15. `@RequestBody` nima?

@RequestBody - HTTP request body ichidagi JSON’ni Java objectga aylantirib beradi.

Masalan frontend shunday JSON yuboradi:

{
  "name": "Ali",
  "age": 25
}

Biz Java’da DTO class yozamiz:

public class CreateUserRequest {

    private String name;
    private Integer age;

    public String getName() {
        return name;
    }

    public Integer getAge() {
        return age;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

Controller:

@PostMapping
public String createUser(@RequestBody CreateUserRequest request) {
    return "User yaratildi: " + request.getName();
}

Request:

POST /users
Content-Type: application/json

Body:

{
  "name": "Ali",
  "age": 25
}

Response:

User yaratildi: Ali

16. Lombok bilan DTO

Agar Lombok ishlatsak:

@Getter
@Setter
public class CreateUserRequest {
    private String name;
    private Integer age;
}

Yoki Java record:

public record CreateUserRequest(
        String name,
        Integer age
) {
}

Spring Boot’da record DTO uchun juda qulay.

17. Response object qaytarish

Text emas, object qaytarsak, Spring avtomatik JSON qiladi.

public record UserResponse(
        Long id,
        String name,
        Integer age
) {
}

Controller:

@GetMapping("/{id}")
public UserResponse getUser(@PathVariable Long id) {
    return new UserResponse(id, "Ali", 25);
}

Response:

{
  "id": 1,
  "name": "Ali",
  "age": 25
}

18. List qaytarish

@GetMapping
public List<UserResponse> getUsers() {
    return List.of(
            new UserResponse(1L, "Ali", 25),
            new UserResponse(2L, "Vali", 30)
    );
}

Response:

[
  {
    "id": 1,
    "name": "Ali",
    "age": 25
  },
  {
    "id": 2,
    "name": "Vali",
    "age": 30
  }
]

19. `ResponseEntity` nima?

ResponseEntity - HTTP response’ni to‘liq nazorat qilish uchun ishlatiladi.

U orqali quyidagilarni belgilaymiz:

Response body
HTTP status code
Header

Oddiy misol:

@GetMapping("/{id}")
public ResponseEntity<UserResponse> getUser(@PathVariable Long id) {
    UserResponse response = new UserResponse(id, "Ali", 25);
    return ResponseEntity.ok(response);
}

Bu:

HTTP status: 200 OK
Body: user JSON

20. `201 Created` qaytarish

Yangi resource yaratilganda 201 Created qaytarish yaxshi.

@PostMapping
public ResponseEntity<UserResponse> createUser(
        @RequestBody CreateUserRequest request
) {
    UserResponse response = new UserResponse(1L, request.name(), request.age());

    return ResponseEntity
            .status(HttpStatus.CREATED)
            .body(response);
}

Response:

HTTP status: 201 Created

Body:

{
  "id": 1,
  "name": "Ali",
  "age": 25
}

21. `204 No Content` qaytarish

Delete qilinganda ko‘pincha body qaytarilmaydi.

@DeleteMapping("/{id}")
public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
    return ResponseEntity.noContent().build();
}

Response:

HTTP status: 204 No Content
Body yo‘q

22. HTTP status codes

Eng kerakli statuslar:

Status	Nomi	Qachon ishlatiladi?
`200`	OK	Muvaffaqiyatli GET/PUT
`201`	Created	Yangi ma’lumot yaratildi
`204`	No Content	Muvaffaqiyatli, lekin body yo‘q
`400`	Bad Request	Noto‘g‘ri request
`401`	Unauthorized	Login qilmagan
`403`	Forbidden	Ruxsat yo‘q
`404`	Not Found	Ma’lumot topilmadi
`409`	Conflict	Ma’lumot conflict bo‘ldi
`500`	Internal Server Error	Server ichki xatosi

23. To‘liq mini REST API

`UserResponse`

public record UserResponse(
        Long id,
        String name,
        Integer age
) {
}

`CreateUserRequest`

public record CreateUserRequest(
        String name,
        Integer age
) {
}

`UserController`

@RestController
@RequestMapping("/users")
public class UserController {

    @GetMapping
    public List<UserResponse> getUsers() {
        return List.of(
                new UserResponse(1L, "Ali", 25),
                new UserResponse(2L, "Vali", 30)
        );
    }

    @GetMapping("/{id}")
    public ResponseEntity<UserResponse> getUser(@PathVariable Long id) {
        UserResponse response = new UserResponse(id, "Ali", 25);
        return ResponseEntity.ok(response);
    }

    @PostMapping
    public ResponseEntity<UserResponse> createUser(
            @RequestBody CreateUserRequest request
    ) {
        UserResponse response = new UserResponse(3L, request.name(), request.age());

        return ResponseEntity
                .status(HttpStatus.CREATED)
                .body(response);
    }

    @PutMapping("/{id}")
    public ResponseEntity<UserResponse> updateUser(
            @PathVariable Long id,
            @RequestBody CreateUserRequest request
    ) {
        UserResponse response = new UserResponse(id, request.name(), request.age());
        return ResponseEntity.ok(response);
    }

    @DeleteMapping("/{id}")
    public ResponseEntity<Void> deleteUser(@PathVariable Long id) {
        return ResponseEntity.noContent().build();
    }
}

24. Postman yoki browser orqali test

Browser bilan

Browser faqat GET endpointlarni oson test qiladi:

http://localhost:8080/users
http://localhost:8080/users/1

Postman bilan

POST, PUT, DELETE uchun Postman ishlatish qulay.

POST request:

POST http://localhost:8080/users
Content-Type: application/json

Body:

{
  "name": "Hasan",
  "age": 22
}

Expected response:

{
  "id": 3,
  "name": "Hasan",
  "age": 22
}

Status:

201 Created

25. `curl` bilan test

Terminalda:

curl http://localhost:8080/users

POST:

curl -X POST http://localhost:8080/users \
  -H "Content-Type: application/json" \
  -d '{"name":"Hasan","age":22}'

PUT:

curl -X PUT http://localhost:8080/users/1 \
  -H "Content-Type: application/json" \
  -d '{"name":"Ali Updated","age":26}'

DELETE:

curl -X DELETE http://localhost:8080/users/1

26. Controller → Service → Repository qilish

Bo'shlanishiga controller ichida hamma narsani yozib ketish mumkin, lekin real loyihada bu noto‘g‘ri.

Yaxshi structure:

controller → service → repository

Masalan:

UserController request oladi
UserService biznes logika bajaradi
UserRepository data bilan ishlaydi

`UserService`

@Service
public class UserService {

    public List<UserResponse> getUsers() {
        return List.of(
                new UserResponse(1L, "Ali", 25),
                new UserResponse(2L, "Vali", 30)
        );
    }

    public UserResponse getUser(Long id) {
        return new UserResponse(id, "Ali", 25);
    }

    public UserResponse createUser(CreateUserRequest request) {
        return new UserResponse(3L, request.name(), request.age());
    }
}

`UserController`

@RestController
@RequestMapping("/users")
public class UserController {

    private final UserService userService;

    public UserController(UserService userService) {
        this.userService = userService;
    }

    @GetMapping
    public List<UserResponse> getUsers() {
        return userService.getUsers();
    }

    @GetMapping("/{id}")
    public ResponseEntity<UserResponse> getUser(@PathVariable Long id) {
        return ResponseEntity.ok(userService.getUser(id));
    }

    @PostMapping
    public ResponseEntity<UserResponse> createUser(
            @RequestBody CreateUserRequest request
    ) {
        return ResponseEntity
                .status(HttpStatus.CREATED)
                .body(userService.createUser(request));
    }
}

Bu yaxshiroq, chunki controller faqat request/response bilan ishlaydi.

27. Eng ko‘p xatolar

1. `@RestController` yozmaslik

Xato:

public class UserController {
}

To‘g‘ri:

@RestController
public class UserController {
}

2. `@RequestBody` unutish

Xato:

@PostMapping
public String createUser(CreateUserRequest request) {
    return request.name();
}

To‘g‘ri:

@PostMapping
public String createUser(@RequestBody CreateUserRequest request) {
    return request.name();
}

3. `Content-Type` bermaslik

POST request yuborganda header kerak:

Content-Type: application/json

Aks holda Spring body’ni to‘g‘ri o‘qimasligi mumkin.

4. Path nomlari chalkashishi

Xato:

@GetMapping("/{id}")
public String getUser(@PathVariable Long userId) {
    return userId.toString();
}

Bu holatda Spring ba’zan id bilan userIdni moslay olmaydi.

To‘g‘ri:

@GetMapping("/{id}")
public String getUser(@PathVariable("id") Long userId) {
    return userId.toString();
}

28. REST API naming qoidalari

Yaxshi endpointlar:

GET    /users
GET    /users/1
POST   /users
PUT    /users/1
DELETE /users/1

Yomonroq endpointlar:

GET /getUsers
POST /createUser
POST /deleteUser
GET /userDelete

REST’da odatda fe’l emas, resource nomi ishlatiladi:

/users
/products
/orders
/payments

Amalni HTTP method bildiradi:

GET    → olish
POST   → yaratish
PUT    → yangilash
DELETE → o‘chirish

29. Interview uchun javoblar

Savol: `@RestController` nima?

@RestController Spring’da REST API controller yaratish uchun ishlatiladi. U methoddan qaytgan qiymatni avtomatik HTTP response body qilib qaytaradi.

Savol: `@PathVariable` va `@RequestParam` farqi?

@PathVariable URL path ichidagi qiymatni oladi, masalan /users/1. @RequestParam esa query parameter oladi, masalan /users?name=Ali.

Savol: `@RequestBody` nima?

@RequestBody HTTP request body ichidagi JSON’ni Java obyektga convert qilib beradi.

Savol: `ResponseEntity` nima uchun kerak?

ResponseEntity response body, HTTP status code va headerlarni boshqarish uchun kerak.

30. Bo'shlangich java developer uchun xulosa

Bugungi mavzudan eslab qoling:

@RestController - REST API controller
@RequestMapping - umumiy path
@GetMapping - ma’lumot olish
@PostMapping - yangi ma’lumot yaratish
@PutMapping - ma’lumot yangilash
@DeleteMapping - ma’lumot o‘chirish
@PathVariable - URL pathdan qiymat olish
@RequestParam - query parameter olish
@RequestBody - JSON body olish
ResponseEntity - status/body/header boshqarish

31. Amaliy vazifa

Product API yoz:

GET    /products
GET    /products/1
POST   /products
PUT    /products/1
DELETE /products/1

DTO:

public record ProductRequest(
        String name,
        Double price
) {
}

Response:

public record ProductResponse(
        Long id,
        String name,
        Double price
) {
}

Controller service orqali ishlasin:

ProductController → ProductService

REST API

1. REST API nima?

2. REST API qayerda ishlatiladi?

3. HTTP methodlar

4. Birinchi controller

5. @RestController nima?

6. @RequestMapping nima?

7. @GetMapping

9. @PutMapping

10. @DeleteMapping

11. To‘liq CRUD endpointlar

12. @PathVariable nima?

@PathVariable nomi boshqacha bo‘lsa

13. @RequestParam nima?

Bir nechta @RequestParam

Optional @RequestParam

14. @PathVariable vs @RequestParam

15. @RequestBody nima?

16. Lombok bilan DTO

17. Response object qaytarish

18. List qaytarish

19. ResponseEntity nima?

20. 201 Created qaytarish

21. 204 No Content qaytarish

22. HTTP status codes

23. To‘liq mini REST API

UserResponse

CreateUserRequest

UserController

24. Postman yoki browser orqali test

Browser bilan

Postman bilan

25. curl bilan test

26. Controller → Service → Repository qilish

UserService

UserController

27. Eng ko‘p xatolar

1. @RestController yozmaslik

2. @RequestBody unutish

3. Content-Type bermaslik

4. Path nomlari chalkashishi

28. REST API naming qoidalari

29. Interview uchun javoblar

Savol: @RestController nima?

Savol: @PathVariable va @RequestParam farqi?

Savol: @RequestBody nima?

Savol: ResponseEntity nima uchun kerak?

30. Bo'shlangich java developer uchun xulosa

31. Amaliy vazifa

5. `@RestController` nima?

6. `@RequestMapping` nima?

7. `@GetMapping`

9. `@PutMapping`

10. `@DeleteMapping`

12. `@PathVariable` nima?

`@PathVariable` nomi boshqacha bo‘lsa

13. `@RequestParam` nima?

Bir nechta `@RequestParam`

Optional `@RequestParam`

14. `@PathVariable` vs `@RequestParam`

15. `@RequestBody` nima?

19. `ResponseEntity` nima?

20. `201 Created` qaytarish

21. `204 No Content` qaytarish

`UserResponse`

`CreateUserRequest`

`UserController`

25. `curl` bilan test

`UserService`

`UserController`

1. `@RestController` yozmaslik

2. `@RequestBody` unutish

3. `Content-Type` bermaslik

Savol: `@RestController` nima?

Savol: `@PathVariable` va `@RequestParam` farqi?

Savol: `@RequestBody` nima?

Savol: `ResponseEntity` nima uchun kerak?