@GetMapping("/user")
public String getUser(
    @RequestParam String name, 
    @RequestParam(defaultValue = "20") int age) {
    return "Name: " + name + ", Age: " + age;
}

@GetMapping("/product/{id}")
public String getProduct(@PathVariable Long id) {
    return "Product ID: " + id;
}

@GetMapping("/order/{orderId}")
public String getOrder(
    @PathVariable String orderId,
    @RequestParam String status) {
    return "Order " + orderId + " is " + status;
}

public class SearchParams {
    private String keyword;
    private int page = 1;
    private int size = 20;
    // getters/setters方法
}
?
@GetMapping("/search")
public String search(SearchParams params) {
    return "Searching: " + params.getKeyword() 
           + " Page: " + params.getPage();
}

public class UserQuery {
    private String name;
    private Address address;
    // getters/setters
}
?
public class Address {
    private String city;
    private String zip;
}
?
@GetMapping("/user")
public String findUser(UserQuery query) {
    return query.getName() + " in " + query.getAddress().getCity();
}

// User實體
public class User {
    private String id;
    private String name;
    private String email;
    // getters/setters
}
?
@PostMapping("/users")
public User createUser(@RequestBody User user) {
    user.setId(UUID.randomUUID().toString());
    return user; // 自動轉(zhuǎn)為JSON
}

@GetMapping("/products")
public String getProducts(@RequestParam List<Long> ids) {
    return "IDs: " + ids.toString();
}

@PostMapping("/batch")
public String batchCreate(@RequestBody List<Item> items) {
    return "Created " + items.size() + " items";
}

@GetMapping("/events")
public String getEvents(@DateTimeFormat(pattern = "yyyy-MM-dd") Date date) {
    return "Events on: " + date.toString();
}

@GetMapping("/optional")
public String optionalParam(@RequestParam(required = false) String filter) {
    return filter != null ? "Filter: " + filter : "No filter";
}

@GetMapping("/auth")
public String auth(@RequestHeader("Authorization") String token) {
    return "Token: " + token.substring(0, 5) + "...";
}

@PostMapping("/upload")
public String uploadFile(@RequestParam("file") MultipartFile file) {
    return "File received: " + file.getOriginalFilename() 
           + " Size: " + file.getSize();
}

public class Registration {
    @NotBlank
    private String username;
    @Email
    private String email;
    @Min(18)
    private int age;
}
@PostMapping("/register")
public ResponseEntity<?> register(@Valid @RequestBody Registration form) {
    // 自動驗證參數(shù)
    return ResponseEntity.ok("Valid");
}
// 全局異常處理
@ControllerAdvice
public class ValidationHandler {
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    @ExceptionHandler(MethodArgumentNotValidException.class)
    public Map<String, String> handleValidation(MethodArgumentNotValidException ex) {
        Map<String, String> errors = new HashMap<>();
        ex.getBindingResult().getFieldErrors().forEach(error -> 
            errors.put(error.getField(), error.getDefaultMessage()));
        return errors;
    }
}