// 只返回狀態(tài)碼
ResponseEntity<Void> response = ResponseEntity.ok().build();

// 返回狀態(tài)碼和響應(yīng)體
ResponseEntity<String> response = ResponseEntity.ok("操作成功");

// 自定義HTTP狀態(tài)碼
ResponseEntity<String> response = ResponseEntity.status(HttpStatus.CREATED).body("資源已創(chuàng)建");

// 200 OK
ResponseEntity.ok()

// 201 Created
ResponseEntity.created(URI location)

// 204 No Content
ResponseEntity.noContent()

// 400 Bad Request
ResponseEntity.badRequest()

// 404 Not Found
ResponseEntity.notFound()

// 500 Internal Server Error
ResponseEntity.internalServerError()

@GetMapping("/custom-header")
public ResponseEntity<String> customHeader() {
    HttpHeaders headers = new HttpHeaders();
    headers.add("Custom-Header", "Custom-Value");
    return ResponseEntity.ok()
            .headers(headers)
            .body("帶有自定義響應(yīng)頭的響應(yīng)");
}

@GetMapping("/download")
public ResponseEntity<Resource> downloadFile() throws IOException {
    Path filePath = Paths.get("path/to/file.txt");
    Resource resource = new InputStreamResource(Files.newInputStream(filePath));
    
    return ResponseEntity.ok()
            .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + filePath.getFileName() + "\"")
            .contentType(MediaType.APPLICATION_OCTET_STREAM)
            .body(resource);
}

@GetMapping("/users")
public ResponseEntity<Page<User>> getUsers(
        @RequestParam(defaultValue = "0") int page,
        @RequestParam(defaultValue = "10") int size) {
    
    Pageable pageable = PageRequest.of(page, size);
    Page<User> users = userService.findAll(pageable);
    
    return ResponseEntity.ok()
            .header("X-Total-Count", String.valueOf(users.getTotalElements()))
            .body(users);
}

@ControllerAdvice
public class GlobalExceptionHandler {
    
    @ExceptionHandler(ResourceNotFoundException.class)
    public ResponseEntity<ErrorResponse> handleResourceNotFound(ResourceNotFoundException ex) {
        ErrorResponse error = new ErrorResponse(
            HttpStatus.NOT_FOUND.value(),
            ex.getMessage(),
            System.currentTimeMillis()
        );
        return new ResponseEntity<>(error, HttpStatus.NOT_FOUND);
    }
    
    @ExceptionHandler(Exception.class)
    public ResponseEntity<ErrorResponse> handleAllExceptions(Exception ex) {
        ErrorResponse error = new ErrorResponse(
            HttpStatus.INTERNAL_SERVER_ERROR.value(),
            "服務(wù)器內(nèi)部錯誤",
            System.currentTimeMillis()
        );
        return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);
    }
}

public class ErrorResponse {
    private int status;
    private String message;
    private long timestamp;
    private List<String> details;
    
    // 構(gòu)造方法、getter和setter
}

@PostMapping("/users")
public ResponseEntity<User> createUser(@RequestBody User user) {
    User savedUser = userService.save(user);
    URI location = ServletUriComponentsBuilder.fromCurrentRequest()
            .path("/{id}")
            .buildAndExpand(savedUser.getId())
            .toUri();
    
    return ResponseEntity.created(location).body(savedUser);
}

@GetMapping("/users/{id}")
public ResponseEntity<User> getUser(@PathVariable Long id) {
    return userService.findById(id)
            .map(user -> ResponseEntity.ok(user))
            .orElse(ResponseEntity.notFound().build());
}

@PutMapping("/users/{id}")
public ResponseEntity<User> updateUser(@PathVariable Long id, @RequestBody User user) {
    return ResponseEntity.ok(userService.update(id, user));
}

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

public class ApiResponse<T> {
    private boolean success;
    private String message;
    private T data;
    
    // 構(gòu)造方法、getter和setter
}

@GetMapping("/products/{id}")
public ResponseEntity<ApiResponse<Product>> getProduct(@PathVariable Long id) {
    return productService.findById(id)
            .map(product -> ResponseEntity.ok(
                new ApiResponse<>(true, "成功", product)))
            .orElse(ResponseEntity.ok(
                new ApiResponse<>(false, "產(chǎn)品不存在", null)));
}