예외 자동변환하는 DefaultHandlerExceptionResolver

 

만약 localhost:8090/api/response-handler-ex?data=111 라는 url에서 data가 Interger 라면 

localhost:8090/api/response-handler-ex?data=qqq 라고 넣으면 typeMissMatch 오류가 날 것이다.

 

그럼 서버에서 오류가 나기 때문에 원래는 500이 나야하지만, 사용자가 잘못 넣은 값이기 때문에 400으로 처리하는 것이 맞을 것이다.

 

 

하지만 부트는 타입미스매치를 자동으로 400으로 처리해 준다.

 

아래의 디폴트핸들러익셉션리졸버가 그것을 가능하게 해준다

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//

package org.springframework.web.servlet.mvc.support;

import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.ConversionNotSupportedException;
import org.springframework.beans.TypeMismatchException;
import org.springframework.http.HttpHeaders;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.lang.Nullable;
import org.springframework.validation.BindException;
import org.springframework.web.ErrorResponse;
import org.springframework.web.HttpMediaTypeNotAcceptableException;
import org.springframework.web.HttpMediaTypeNotSupportedException;
import org.springframework.web.HttpRequestMethodNotSupportedException;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.MissingPathVariableException;
import org.springframework.web.bind.MissingServletRequestParameterException;
import org.springframework.web.bind.ServletRequestBindingException;
import org.springframework.web.context.request.async.AsyncRequestTimeoutException;
import org.springframework.web.multipart.support.MissingServletRequestPartException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.NoHandlerFoundException;
import org.springframework.web.servlet.handler.AbstractHandlerExceptionResolver;

public class DefaultHandlerExceptionResolver extends AbstractHandlerExceptionResolver {
    public static final String PAGE_NOT_FOUND_LOG_CATEGORY = "org.springframework.web.servlet.PageNotFound";
    protected static final Log pageNotFoundLogger = LogFactory.getLog("org.springframework.web.servlet.PageNotFound");

    public DefaultHandlerExceptionResolver() {
        this.setOrder(Integer.MAX_VALUE);
        this.setWarnLogCategory(this.getClass().getName());
    }

    @Nullable
    protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
        try {
            if (ex instanceof ErrorResponse errorResponse) {
                ModelAndView mav = null;
                if (ex instanceof HttpRequestMethodNotSupportedException theEx) {
                    mav = this.handleHttpRequestMethodNotSupported(theEx, request, response, handler);
                } else if (ex instanceof HttpMediaTypeNotSupportedException theEx) {
                    mav = this.handleHttpMediaTypeNotSupported(theEx, request, response, handler);
                } else if (ex instanceof HttpMediaTypeNotAcceptableException theEx) {
                    mav = this.handleHttpMediaTypeNotAcceptable(theEx, request, response, handler);
                } else if (ex instanceof MissingPathVariableException theEx) {
                    mav = this.handleMissingPathVariable(theEx, request, response, handler);
                } else if (ex instanceof MissingServletRequestParameterException theEx) {
                    mav = this.handleMissingServletRequestParameter(theEx, request, response, handler);
                } else if (ex instanceof MissingServletRequestPartException theEx) {
                    mav = this.handleMissingServletRequestPartException(theEx, request, response, handler);
                } else if (ex instanceof ServletRequestBindingException theEx) {
                    mav = this.handleServletRequestBindingException(theEx, request, response, handler);
                } else if (ex instanceof MethodArgumentNotValidException theEx) {
                    mav = this.handleMethodArgumentNotValidException(theEx, request, response, handler);
                } else if (ex instanceof NoHandlerFoundException theEx) {
                    mav = this.handleNoHandlerFoundException(theEx, request, response, handler);
                } else if (ex instanceof AsyncRequestTimeoutException theEx) {
                    mav = this.handleAsyncRequestTimeoutException(theEx, request, response, handler);
                }

                return mav != null ? mav : this.handleErrorResponse(errorResponse, request, response, handler);
            }

            if (ex instanceof ConversionNotSupportedException theEx) {
                return this.handleConversionNotSupported(theEx, request, response, handler);
            }

            if (ex instanceof TypeMismatchException theEx) {
                return this.handleTypeMismatch(theEx, request, response, handler);
            }

            if (ex instanceof HttpMessageNotReadableException theEx) {
                return this.handleHttpMessageNotReadable(theEx, request, response, handler);
            }

            if (ex instanceof HttpMessageNotWritableException theEx) {
                return this.handleHttpMessageNotWritable(theEx, request, response, handler);
            }

            if (ex instanceof BindException theEx) {
                return this.handleBindException(theEx, request, response, handler);
            }
        } catch (Exception var17) {
            if (this.logger.isWarnEnabled()) {
                this.logger.warn("Failure while trying to resolve exception [" + ex.getClass().getName() + "]", var17);
            }
        }

        return null;
    }

    @Nullable
    protected ModelAndView handleHttpRequestMethodNotSupported(HttpRequestMethodNotSupportedException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleHttpMediaTypeNotSupported(HttpMediaTypeNotSupportedException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleHttpMediaTypeNotAcceptable(HttpMediaTypeNotAcceptableException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleMissingPathVariable(MissingPathVariableException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleMissingServletRequestParameter(MissingServletRequestParameterException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleMissingServletRequestPartException(MissingServletRequestPartException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleServletRequestBindingException(ServletRequestBindingException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleMethodArgumentNotValidException(MethodArgumentNotValidException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    @Nullable
    protected ModelAndView handleNoHandlerFoundException(NoHandlerFoundException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        pageNotFoundLogger.warn(ex.getMessage());
        return null;
    }

    @Nullable
    protected ModelAndView handleAsyncRequestTimeoutException(AsyncRequestTimeoutException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        return null;
    }

    protected ModelAndView handleErrorResponse(ErrorResponse errorResponse, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        if (!response.isCommitted()) {
            HttpHeaders headers = errorResponse.getHeaders();
            headers.forEach((name, values) -> {
                values.forEach((value) -> {
                    response.addHeader(name, value);
                });
            });
            int status = errorResponse.getStatusCode().value();
            String message = errorResponse.getBody().getDetail();
            if (message != null) {
                response.sendError(status, message);
            } else {
                response.sendError(status);
            }
        } else {
            this.logger.warn("Ignoring exception, response committed. : " + errorResponse);
        }

        return new ModelAndView();
    }

    protected ModelAndView handleConversionNotSupported(ConversionNotSupportedException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        this.sendServerError(ex, request, response);
        return new ModelAndView();
    }

    protected ModelAndView handleTypeMismatch(TypeMismatchException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        response.sendError(400);
        return new ModelAndView();
    }

    protected ModelAndView handleHttpMessageNotReadable(HttpMessageNotReadableException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        response.sendError(400);
        return new ModelAndView();
    }

    protected ModelAndView handleHttpMessageNotWritable(HttpMessageNotWritableException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        this.sendServerError(ex, request, response);
        return new ModelAndView();
    }

    /** @deprecated */
    @Deprecated(
        since = "6.0",
        forRemoval = true
    )
    protected ModelAndView handleBindException(BindException ex, HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
        response.sendError(400);
        return new ModelAndView();
    }

    protected void sendServerError(Exception ex, HttpServletRequest request, HttpServletResponse response) throws IOException {
        request.setAttribute("jakarta.servlet.error.exception", ex);
        response.sendError(500);
    }
}