# 13 예외처리 p230 - src/main/java/mvc/error/controller/ErrorController ```java @Slf4j @Controller @RequestMapping("/error") public class ErrorController { @GetMapping("/test") public void getTestError(HttpServletResponse resp) throws IOException { resp.sendError(400, "에러 발생"); } @GetMapping("/404") public String get400Error(){ return "error/404"; } // 404 에러 처리 - JSON 응답 @GetMapping(value = "/404", produces = "application/json") @ResponseBody public ResponseEntity> get404ErrorJson() { Map errorDetails = new HashMap<>(); errorDetails.put("status", 404); errorDetails.put("error", "Not Found"); errorDetails.put("message", "Page not found"); errorDetails.put("path", "/error/404"); return new ResponseEntity<>(errorDetails, HttpStatus.NOT_FOUND); } @GetMapping("/500") public String get500Error() { return "error/500"; } // 500 에러 처리 - JSON 응답 @GetMapping(value = "/500", produces = "application/json") @ResponseBody public ResponseEntity> get500ErrorJson() { Map errorDetails = new HashMap<>(); errorDetails.put("status", 500); errorDetails.put("error", "Internal Server Error"); errorDetails.put("message", "An unexpected error occurred"); errorDetails.put("path", "/error/500"); return new ResponseEntity<>(errorDetails, HttpStatus.INTERNAL_SERVER_ERROR); } @GetMapping("/runtime") public void runtimeException() { throw new RuntimeException("runtime exception 발생"); } // Runtime Exception 처리 - JSON 응답 @GetMapping(value = "/runtime", produces = "application/json") @ResponseBody public ResponseEntity> runtimeExceptionJson() { Map errorDetails = new HashMap<>(); errorDetails.put("status", 500); errorDetails.put("error", "Internal Server Error"); errorDetails.put("message", "Runtime exception 발생"); errorDetails.put("path", "/error/runtime"); return new ResponseEntity<>(errorDetails, HttpStatus.INTERNAL_SERVER_ERROR); } @GetMapping(value = "/illegal") @ResponseBody public ResponseEntity> IllegalExceptionHtml() { throw new ResponseStatusException(HttpStatus.NOT_FOUND, "타입 에러", new IllegalArgumentException()); } @GetMapping(value = "/illegal", produces = "application/json") @ResponseBody public ResponseEntity> IllegalExceptionJson() { throw new ResponseStatusException(HttpStatus.NOT_FOUND, "타입 에러", new IllegalArgumentException()); } } ``` p232 - src/main/java/mvc/error/CustomWebServerFactoryCustomizer ```java @Component public class CustomWebServerFactoryCustomizer implements WebServerFactoryCustomizer { @Override public void customize(ConfigurableWebServerFactory factory) { // 404 에러 페이지 등록 factory.addErrorPages(new ErrorPage(HttpStatus.NOT_FOUND, "/error/404")); // 500 에러 페이지 등록 factory.addErrorPages(new ErrorPage(HttpStatus.INTERNAL_SERVER_ERROR, "/error/500")); } } ``` p233 - src/main/resources/templates/error/4xx.html, 404.html, 500.html ```html 400 - Bad Request

400 - Bad Request

Timestamp: 2024-10-02T10:15:30

Status: 400

Error: Bad Request

Exception: org.springframework.web.bind.MissingServletRequestParameterException

Message: Required String parameter 'param' is not present

Path: /requested/path

요청하신 페이지를 찾을 수 없습니다.

``` ```html 404 - Bad Request

404 - Bad Request

Timestamp: 2024-10-02T10:15:30

Status: 400

Error: Bad Request

Exception: org.springframework.web.bind.MissingServletRequestParameterException

Message: Required String parameter 'param' is not present

Path: /requested/path

요청하신 페이지를 찾을 수 없습니다.

``` ```html 500 - Internal Server Error

500 - Internal Server Error

서버에 오류가 발생했습니다. 잠시 후 다시 시도해주세요.

``` p234 - src/main/java/mvc/error/ExceptionHandlingFilter ```java @WebFilter("/*") // 모든 요청에 대해 이 필터를 적용합니다. public class ExceptionHandlingFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { // 필터 초기화 (필요한 경우) } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpRequest = (HttpServletRequest) request; HttpServletResponse httpResponse = (HttpServletResponse) response; try { // 다음 필터 또는 서블릿으로 요청 전달 chain.doFilter(request, response); } catch (Exception e) { // 예외 발생 시 500 에러 페이지로 포워딩 handleException(e, httpRequest, httpResponse); } // 404 오류를 감지하여 처리 if (httpResponse.getStatus() == HttpServletResponse.SC_NOT_FOUND) { httpResponse.sendError(HttpServletResponse.SC_NOT_FOUND, "페이지를 찾을 수 없습니다."); } } @Override public void destroy() { // 필터 종료 작업 (필요한 경우) } // 예외를 처리하는 메서드 private void handleException(Exception e, HttpServletRequest request, HttpServletResponse response) throws IOException { // 로그 작성 (선택적) e.printStackTrace(); // 500 에러 페이지로 포워딩 response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "서버 내부 오류가 발생했습니다."); } } ``` p238, 240 - src/main/java/mvc/error/LoggingIntercetor ```java @Slf4j @Component public class LoggingInterceptor implements HandlerInterceptor { // 요청이 컨트롤러에 전달되기 전에 호출 @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) { // 요청별로 고유한 요청 UUID 생성 String requestUUID = UUID.randomUUID().toString(); // 요청 객체에 UUID를 저장 request.setAttribute("requestUUID", requestUUID); log.info("preHandle 요청이 컨트롤러에 전달되기 전에 호출 [{}]: {} {}", requestUUID, request.getMethod(), request.getRequestURI()); return true; } // 컨트롤러 실행 후, 뷰 렌더링 전에 호출 @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) { String requestUUID = (String) request.getAttribute("requestUUID"); log.info("postHandle 컨트롤러 실행 후, 뷰 렌더링 전에 호출 [RequestUUID: {}]", requestUUID); } // 요청 완료 후 (뷰 렌더링 완료 후) 호출 @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { String requestUUID = (String) request.getAttribute("requestUUID"); log.info("afterCompletion 요청 완료 후 (뷰 렌더링 완료 후) 호출 [RequestUUID: {}]", requestUUID); if (ex != null) { log.info("afterCompletion 예외 발생 [RequestUUID: {}]: {}", requestUUID, ex.getMessage()); } } } ``` p239 , 241- src/main/java/mvc/error/WebConfig ```java @Configuration public class WebConfig implements WebMvcConfigurer { private final LoggingInterceptor loggingInterceptor; @Autowired public WebConfig(LoggingInterceptor loggingInterceptor) { this.loggingInterceptor = loggingInterceptor; } @Override public void addInterceptors(InterceptorRegistry registry) { // 모든 요청에 대해 인터셉터 적용 registry.addInterceptor(loggingInterceptor) .addPathPatterns("/**") // 특정 경로에만 적용하려면 "/api/**" 등으로 변경 가능 .excludePathPatterns("/static/**", "/css/**", "/js/**", "/public/**", "/error"); // 특정 경로는 제외 } } ``` p243 - src/resources/templates/error/404.html ```html 404 - Bad Request

404 - Bad Request

Timestamp: 2024-10-02T10:15:30

Status: 400

Error: Bad Request

Exception: org.springframework.web.bind.MissingServletRequestParameterException

Message: Required String parameter 'param' is not present

Path: /requested/path

요청하신 페이지를 찾을 수 없습니다.

``` p246 - src/main/java/mvc/error/GlobalExceptionHandler ```java @ControllerAdvice public class GlobalExceptionHandler { @ExceptionHandler(IllegalArgumentException.class) public ResponseEntity handleIllegalArgumentException(IllegalArgumentException ex) { return ResponseEntity.status(HttpStatus.BAD_REQUEST) .body("잘못된 요청입니다: " + ex.getMessage()); } @ExceptionHandler(Exception.class) public ResponseEntity handleGenericException(Exception ex) { return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR) .body("서버에서 오류가 발생했습니다: " + ex.getMessage()); } } ``` p247 - src/main/java/mvc/error/PackageSpecificExceptionHandler, SpecificControllerExceptionHandler ```java @ControllerAdvice("mvc.error.controller") public class PackageSpecificExceptionHandler { } ``` ```java @ControllerAdvice(assignableTypes = {ErrorController.class}) public class SpecificControllerExceptionHandler { } ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://team-everywhere.gitbook.io/backend/spring/spring-boot/13.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.