4. exception , exceptionhandler , interceptor , webConfig

예외처리

먼저 exceptionhandler 라는 패키지와 
우리가 원하는 예외들을 담을수 있게 
common/exception 패키지 두개를 만들자.

exceptionhandler 에는 두개의 클래스가 있다.
@Slf4j
@RestControllerAdvice
@Order(value = Integer.MIN_VALUE)
public class ApiExceptionHandler {

    @ExceptionHandler(value = ApiException.class)
    public ResponseEntity<Object> apiException(
            ApiException apiException
    ){
        log.error("",apiException);

        var errorCode = apiException.getErrorCodeIfs();

        return ResponseEntity
                .status(errorCode.getHttpStatusCode())
                .body(
                        Api.ERROR(errorCode,apiException.getErrorDescription())
                );
    }
}


@Slf4j
@RestControllerAdvice
@Order(value = Integer.MAX_VALUE) //가장 마지막에 실행 적용
public class GlobalExceptionHandler {

    @ExceptionHandler(value = Exception.class)
    public ResponseEntity<Api<Object>> exception(
            Exception exception
    ){
        log.error("",exception);

        return ResponseEntity
                .status(500)
                .body(
                        Api.ERROR(ErrorCode.SERVER_ERROR)
                );
    }
}



@Getter
public class ApiException extends RuntimeException implements  ApiExceptionIfs{

    private final ErrorCodeIfs errorCodeIfs;
    private final String errorDescription;

    public ApiException(ErrorCodeIfs errorCodeIfs){
        super(errorCodeIfs.getDescription());
        this.errorCodeIfs=errorCodeIfs;
        this.errorDescription = errorCodeIfs.getDescription();
    }

    public ApiException(ErrorCodeIfs errorCodeIfs, String errorDescription){
        super(errorDescription);
        this.errorCodeIfs=errorCodeIfs;
        this.errorDescription =errorDescription;
    }

    public ApiException(ErrorCodeIfs errorCodeIfs, Throwable tx){
        super(tx);
        this.errorCodeIfs=errorCodeIfs;
        this.errorDescription = errorCodeIfs.getDescription();
    }

    public ApiException(ErrorCodeIfs errorCodeIfs, Throwable tx,  String errorDescription){
        super(tx);
        this.errorCodeIfs=errorCodeIfs;
        this.errorDescription = errorDescription;
    }
}


public interface ApiExceptionIfs {

    ErrorCodeIfs getErrorCodeIfs();
    String getErrorDescription();
}

다음으로 인터셉터 등록을 해줘야 된다.

먼저 config 패키지에 web 패키지를 만들고
WebConfig 만든다음  아래와 같이 코드를 작성해준다.
WebMvcConfigurer 이놈이 있으면 검증한다는 뜻이다.

@RequiredArgsConstructor
@Configuration
public class WebConfig implements WebMvcConfigurer {

    private final AuthorizationInterceptor authorizationInterceptor;

    private List<String> OPEN_API = List.of(
            "/open-api/**"
    );

    private List<String> DEFAULT_EXCLUDE = List.of(
            "/",
            "favicon.ico",
            "/error"
    );

    private List<String> SWAGGER = List.of(
            "/swagger-ui.html",
            "/swagger-ui/**",
            "/v3/api-docs/**"
    );



    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(authorizationInterceptor)
                .excludePathPatterns(OPEN_API)
                .excludePathPatterns(DEFAULT_EXCLUDE)
                .excludePathPatterns(SWAGGER);
    }
}


authorizationInterceptor 이놈의 코드는 아래와 같다.


@Slf4j
@RequiredArgsConstructor
@Component
public class AuthorizationInterceptor implements HandlerInterceptor {


    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
       log.info("Authorization Interceptor url : {}", request.getRequestURI());

       //WEB , chrome 의 경우 GET, POST OPTIONS = pass
        if(HttpMethod.OPTIONS.matches(request.getMethod())){
            return true;
        }

        //js, html, png, resource 를 요청하는 경우 =pass
        if(handler instanceof ResourceHttpRequestHandler){
            return true;
        }

        //ToDo header 검증

        return true;
    }
}