\n
\n<\/div>\n
Application Startup<\/h1>\n
The following is conceptually similar to Spring Boot\u2019s @SpringBootApplication<\/code> annotated class and SpringApplication.run()<\/code>.<\/p>\nFastAPI<\/h2>\nfrom fastapi import FastAPI\r\nfrom app.routes.user_routes import router as user_router\r\nfrom app.routes.order_routes import router as order_router\r\n\r\napp = FastAPI()\r\n\r\napp.include_router(user_router)\r\napp.include_router(order_router)<\/code><\/pre>\nSpring Boot Equivalent<\/h2>\n@SpringBootApplication\r\npublic class Application {\r\n public static void main(String[] args) {\r\n SpringApplication.run(Application.class, args);\r\n }\r\n}<\/code><\/pre>\nIn FastAPI:<\/p>\n
\nFastAPI()<\/code> creates the application instance<\/li>\ninclude_router()<\/code> registers REST routes<\/li>\n- The framework automatically exposes Swagger UI<\/li>\n<\/ul>\n
Swagger UI is available at:<\/p>\n
http:\/\/localhost:8000\/docs<\/code><\/pre>\nThis is conceptually similar to Spring Boot applications using:<\/p>\n
\n- springdoc-openapi<\/li>\n
- springfox swagger<\/li>\n<\/ul>\n
\n
\n<\/div>\n
Routes<\/h1>\n
Routes in FastAPI are conceptually similar to Spring Boot Controllers.<\/p>\n
FastAPI<\/h2>\nfrom fastapi import APIRouter, HTTPException\r\nfrom typing import List\r\n\r\nrouter = APIRouter(prefix=\"\/users\", tags=[\"Users\"]<\/span>)\r\n\r\n@router.get(\"\/\", response_model=List[UserResponse]<\/span>)\r\ndef get_users():\r\n return user_service.get_all_users()\r\n\r\n@router.get(\"\/{user_id}\")\r\ndef get_user(user_id: int):\r\n user = user_service.get_user(user_id)\r\n\r\n if not user:\r\n raise HTTPException(status_code=404, detail=\"User not found\")\r\n\r\n return user\r\n\r\n@router.post(\"\/\")\r\ndef create_user(user: UserCreate):\r\n return user_service.create_user(user)<\/code><\/pre>\nSpring Boot Equivalent<\/h2>\n@RestController\r\n@RequestMapping(\"\/users\")\r\npublic class UserController {\r\n\r\n @GetMapping\r\n public List<User> getUsers() {\r\n return userService.getUsers();\r\n }\r\n\r\n @GetMapping(\"\/{id}\")\r\n public User getUser(@PathVariable Long id) {\r\n return userService.getUser(id);\r\n }\r\n\r\n @PostMapping\r\n public User createUser(@RequestBody User user) {\r\n return userService.createUser(user);\r\n }\r\n}<\/code><\/pre>\nSimilarities:<\/p>\n
\n@router.get()<\/code> is similar to @GetMapping<\/code><\/li>\n@router.post()<\/code> is similar to @PostMapping<\/code><\/li>\n- Path parameters work similarly<\/li>\n
- JSON serialization is automatic<\/li>\n<\/ul>\n
\n
\n<\/div>\n
Request Validation<\/h1>\n
FastAPI uses Pydantic models for request validation.<\/p>\n
FastAPI<\/h2>\nfrom pydantic import BaseModel\r\n\r\nclass UserCreate(BaseModel):\r\n first_name: str\r\n last_name: str\r\n email: str<\/code><\/pre>\nThis is similar to Spring Boot DTO validation.<\/p>\n
Spring Boot Equivalent<\/h2>\npublic class UserRequest {\r\n @NotBlank\r\n private String firstName;\r\n\r\n @NotBlank\r\n private String lastName;\r\n\r\n @Email\r\n private String email;\r\n}<\/code><\/pre>\nFastAPI automatically:<\/p>\n