spring ExceptionHandlerExceptionResolver 源码

  • 2022-08-08
  • 浏览 (364)

spring ExceptionHandlerExceptionResolver 代码

文件路径:/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ExceptionHandlerExceptionResolver.java

/*
 * Copyright 2002-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.servlet.mvc.method.annotation;

import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import org.springframework.aop.support.AopUtils;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.SpringProperties;
import org.springframework.http.HttpStatusCode;
import org.springframework.http.converter.ByteArrayHttpMessageConverter;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
import org.springframework.http.converter.xml.SourceHttpMessageConverter;
import org.springframework.lang.Nullable;
import org.springframework.ui.ModelMap;
import org.springframework.web.accept.ContentNegotiationManager;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.context.request.ServletWebRequest;
import org.springframework.web.method.ControllerAdviceBean;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.method.annotation.ExceptionHandlerMethodResolver;
import org.springframework.web.method.annotation.MapMethodProcessor;
import org.springframework.web.method.annotation.ModelMethodProcessor;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.HandlerMethodArgumentResolverComposite;
import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
import org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite;
import org.springframework.web.method.support.ModelAndViewContainer;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.handler.AbstractHandlerMethodExceptionResolver;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;
import org.springframework.web.servlet.support.RequestContextUtils;

/**
 * An {@link AbstractHandlerMethodExceptionResolver} that resolves exceptions
 * through {@code @ExceptionHandler} methods.
 *
 * <p>Support for custom argument and return value types can be added via
 * {@link #setCustomArgumentResolvers} and {@link #setCustomReturnValueHandlers}.
 * Or alternatively to re-configure all argument and return value types use
 * {@link #setArgumentResolvers} and {@link #setReturnValueHandlers(List)}.
 *
 * @author Rossen Stoyanchev
 * @author Juergen Hoeller
 * @author Sebastien Deleuze
 * @since 3.1
 */
public class ExceptionHandlerExceptionResolver extends AbstractHandlerMethodExceptionResolver
		implements ApplicationContextAware, InitializingBean {

	/**
	 * Boolean flag controlled by a {@code spring.xml.ignore} system property that instructs Spring to
	 * ignore XML, i.e. to not initialize the XML-related infrastructure.
	 * <p>The default is "false".
	 */
	private static final boolean shouldIgnoreXml = SpringProperties.getFlag("spring.xml.ignore");


	@Nullable
	private List<HandlerMethodArgumentResolver> customArgumentResolvers;

	@Nullable
	private HandlerMethodArgumentResolverComposite argumentResolvers;

	@Nullable
	private List<HandlerMethodReturnValueHandler> customReturnValueHandlers;

	@Nullable
	private HandlerMethodReturnValueHandlerComposite returnValueHandlers;

	private List<HttpMessageConverter<?>> messageConverters;

	private ContentNegotiationManager contentNegotiationManager = new ContentNegotiationManager();

	private final List<Object> responseBodyAdvice = new ArrayList<>();

	@Nullable
	private ApplicationContext applicationContext;

	private final Map<Class<?>, ExceptionHandlerMethodResolver> exceptionHandlerCache =
			new ConcurrentHashMap<>(64);

	private final Map<ControllerAdviceBean, ExceptionHandlerMethodResolver> exceptionHandlerAdviceCache =
			new LinkedHashMap<>();


	public ExceptionHandlerExceptionResolver() {
		this.messageConverters = new ArrayList<>();
		this.messageConverters.add(new ByteArrayHttpMessageConverter());
		this.messageConverters.add(new StringHttpMessageConverter());
		if(!shouldIgnoreXml) {
			try {
				this.messageConverters.add(new SourceHttpMessageConverter<>());
			}
			catch (Error err) {
				// Ignore when no TransformerFactory implementation is available
			}
		}
		this.messageConverters.add(new AllEncompassingFormHttpMessageConverter());
	}


	/**
	 * Provide resolvers for custom argument types. Custom resolvers are ordered
	 * after built-in ones. To override the built-in support for argument
	 * resolution use {@link #setArgumentResolvers} instead.
	 */
	public void setCustomArgumentResolvers(@Nullable List<HandlerMethodArgumentResolver> argumentResolvers) {
		this.customArgumentResolvers = argumentResolvers;
	}

	/**
	 * Return the custom argument resolvers, or {@code null}.
	 */
	@Nullable
	public List<HandlerMethodArgumentResolver> getCustomArgumentResolvers() {
		return this.customArgumentResolvers;
	}

	/**
	 * Configure the complete list of supported argument types thus overriding
	 * the resolvers that would otherwise be configured by default.
	 */
	public void setArgumentResolvers(@Nullable List<HandlerMethodArgumentResolver> argumentResolvers) {
		if (argumentResolvers == null) {
			this.argumentResolvers = null;
		}
		else {
			this.argumentResolvers = new HandlerMethodArgumentResolverComposite();
			this.argumentResolvers.addResolvers(argumentResolvers);
		}
	}

	/**
	 * Return the configured argument resolvers, or possibly {@code null} if
	 * not initialized yet via {@link #afterPropertiesSet()}.
	 */
	@Nullable
	public HandlerMethodArgumentResolverComposite getArgumentResolvers() {
		return this.argumentResolvers;
	}

	/**
	 * Provide handlers for custom return value types. Custom handlers are
	 * ordered after built-in ones. To override the built-in support for
	 * return value handling use {@link #setReturnValueHandlers}.
	 */
	public void setCustomReturnValueHandlers(@Nullable List<HandlerMethodReturnValueHandler> returnValueHandlers) {
		this.customReturnValueHandlers = returnValueHandlers;
	}

	/**
	 * Return the custom return value handlers, or {@code null}.
	 */
	@Nullable
	public List<HandlerMethodReturnValueHandler> getCustomReturnValueHandlers() {
		return this.customReturnValueHandlers;
	}

	/**
	 * Configure the complete list of supported return value types thus
	 * overriding handlers that would otherwise be configured by default.
	 */
	public void setReturnValueHandlers(@Nullable List<HandlerMethodReturnValueHandler> returnValueHandlers) {
		if (returnValueHandlers == null) {
			this.returnValueHandlers = null;
		}
		else {
			this.returnValueHandlers = new HandlerMethodReturnValueHandlerComposite();
			this.returnValueHandlers.addHandlers(returnValueHandlers);
		}
	}

	/**
	 * Return the configured handlers, or possibly {@code null} if not
	 * initialized yet via {@link #afterPropertiesSet()}.
	 */
	@Nullable
	public HandlerMethodReturnValueHandlerComposite getReturnValueHandlers() {
		return this.returnValueHandlers;
	}

	/**
	 * Set the message body converters to use.
	 * <p>These converters are used to convert from and to HTTP requests and responses.
	 */
	public void setMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
		this.messageConverters = messageConverters;
	}

	/**
	 * Return the configured message body converters.
	 */
	public List<HttpMessageConverter<?>> getMessageConverters() {
		return this.messageConverters;
	}

	/**
	 * Set the {@link ContentNegotiationManager} to use to determine requested media types.
	 * If not set, the default constructor is used.
	 */
	public void setContentNegotiationManager(ContentNegotiationManager contentNegotiationManager) {
		this.contentNegotiationManager = contentNegotiationManager;
	}

	/**
	 * Return the configured {@link ContentNegotiationManager}.
	 */
	public ContentNegotiationManager getContentNegotiationManager() {
		return this.contentNegotiationManager;
	}

	/**
	 * Add one or more components to be invoked after the execution of a controller
	 * method annotated with {@code @ResponseBody} or returning {@code ResponseEntity}
	 * but before the body is written to the response with the selected
	 * {@code HttpMessageConverter}.
	 */
	public void setResponseBodyAdvice(@Nullable List<ResponseBodyAdvice<?>> responseBodyAdvice) {
		if (responseBodyAdvice != null) {
			this.responseBodyAdvice.addAll(responseBodyAdvice);
		}
	}

	@Override
	public void setApplicationContext(@Nullable ApplicationContext applicationContext) {
		this.applicationContext = applicationContext;
	}

	@Nullable
	public ApplicationContext getApplicationContext() {
		return this.applicationContext;
	}


	@Override
	public void afterPropertiesSet() {
		// Do this first, it may add ResponseBodyAdvice beans
		initExceptionHandlerAdviceCache();

		if (this.argumentResolvers == null) {
			List<HandlerMethodArgumentResolver> resolvers = getDefaultArgumentResolvers();
			this.argumentResolvers = new HandlerMethodArgumentResolverComposite().addResolvers(resolvers);
		}
		if (this.returnValueHandlers == null) {
			List<HandlerMethodReturnValueHandler> handlers = getDefaultReturnValueHandlers();
			this.returnValueHandlers = new HandlerMethodReturnValueHandlerComposite().addHandlers(handlers);
		}
	}

	private void initExceptionHandlerAdviceCache() {
		if (getApplicationContext() == null) {
			return;
		}

		List<ControllerAdviceBean> adviceBeans = ControllerAdviceBean.findAnnotatedBeans(getApplicationContext());
		for (ControllerAdviceBean adviceBean : adviceBeans) {
			Class<?> beanType = adviceBean.getBeanType();
			if (beanType == null) {
				throw new IllegalStateException("Unresolvable type for ControllerAdviceBean: " + adviceBean);
			}
			ExceptionHandlerMethodResolver resolver = new ExceptionHandlerMethodResolver(beanType);
			if (resolver.hasExceptionMappings()) {
				this.exceptionHandlerAdviceCache.put(adviceBean, resolver);
			}
			if (ResponseBodyAdvice.class.isAssignableFrom(beanType)) {
				this.responseBodyAdvice.add(adviceBean);
			}
		}

		if (logger.isDebugEnabled()) {
			int handlerSize = this.exceptionHandlerAdviceCache.size();
			int adviceSize = this.responseBodyAdvice.size();
			if (handlerSize == 0 && adviceSize == 0) {
				logger.debug("ControllerAdvice beans: none");
			}
			else {
				logger.debug("ControllerAdvice beans: " +
						handlerSize + " @ExceptionHandler, " + adviceSize + " ResponseBodyAdvice");
			}
		}
	}

	/**
	 * Return an unmodifiable Map with the {@link ControllerAdvice @ControllerAdvice}
	 * beans discovered in the ApplicationContext. The returned map will be empty if
	 * the method is invoked before the bean has been initialized via
	 * {@link #afterPropertiesSet()}.
	 */
	public Map<ControllerAdviceBean, ExceptionHandlerMethodResolver> getExceptionHandlerAdviceCache() {
		return Collections.unmodifiableMap(this.exceptionHandlerAdviceCache);
	}

	/**
	 * Return the list of argument resolvers to use including built-in resolvers
	 * and custom resolvers provided via {@link #setCustomArgumentResolvers}.
	 */
	protected List<HandlerMethodArgumentResolver> getDefaultArgumentResolvers() {
		List<HandlerMethodArgumentResolver> resolvers = new ArrayList<>();

		// Annotation-based argument resolution
		resolvers.add(new SessionAttributeMethodArgumentResolver());
		resolvers.add(new RequestAttributeMethodArgumentResolver());

		// Type-based argument resolution
		resolvers.add(new ServletRequestMethodArgumentResolver());
		resolvers.add(new ServletResponseMethodArgumentResolver());
		resolvers.add(new RedirectAttributesMethodArgumentResolver());
		resolvers.add(new ModelMethodProcessor());

		// Custom arguments
		if (getCustomArgumentResolvers() != null) {
			resolvers.addAll(getCustomArgumentResolvers());
		}

		// Catch-all
		resolvers.add(new PrincipalMethodArgumentResolver());

		return resolvers;
	}

	/**
	 * Return the list of return value handlers to use including built-in and
	 * custom handlers provided via {@link #setReturnValueHandlers}.
	 */
	protected List<HandlerMethodReturnValueHandler> getDefaultReturnValueHandlers() {
		List<HandlerMethodReturnValueHandler> handlers = new ArrayList<>();

		// Single-purpose return value types
		handlers.add(new ModelAndViewMethodReturnValueHandler());
		handlers.add(new ModelMethodProcessor());
		handlers.add(new ViewMethodReturnValueHandler());
		handlers.add(new HttpEntityMethodProcessor(
				getMessageConverters(), this.contentNegotiationManager, this.responseBodyAdvice));

		// Annotation-based return value types
		handlers.add(new ServletModelAttributeMethodProcessor(false));
		handlers.add(new RequestResponseBodyMethodProcessor(
				getMessageConverters(), this.contentNegotiationManager, this.responseBodyAdvice));

		// Multi-purpose return value types
		handlers.add(new ViewNameMethodReturnValueHandler());
		handlers.add(new MapMethodProcessor());

		// Custom return value types
		if (getCustomReturnValueHandlers() != null) {
			handlers.addAll(getCustomReturnValueHandlers());
		}

		// Catch-all
		handlers.add(new ServletModelAttributeMethodProcessor(true));

		return handlers;
	}

	@Override
	protected boolean hasGlobalExceptionHandlers() {
		return !this.exceptionHandlerAdviceCache.isEmpty();
	}

	/**
	 * Find an {@code @ExceptionHandler} method and invoke it to handle the raised exception.
	 */
	@Override
	@Nullable
	protected ModelAndView doResolveHandlerMethodException(HttpServletRequest request,
			HttpServletResponse response, @Nullable HandlerMethod handlerMethod, Exception exception) {

		ServletInvocableHandlerMethod exceptionHandlerMethod = getExceptionHandlerMethod(handlerMethod, exception);
		if (exceptionHandlerMethod == null) {
			return null;
		}

		if (this.argumentResolvers != null) {
			exceptionHandlerMethod.setHandlerMethodArgumentResolvers(this.argumentResolvers);
		}
		if (this.returnValueHandlers != null) {
			exceptionHandlerMethod.setHandlerMethodReturnValueHandlers(this.returnValueHandlers);
		}

		ServletWebRequest webRequest = new ServletWebRequest(request, response);
		ModelAndViewContainer mavContainer = new ModelAndViewContainer();

		ArrayList<Throwable> exceptions = new ArrayList<>();
		try {
			if (logger.isDebugEnabled()) {
				logger.debug("Using @ExceptionHandler " + exceptionHandlerMethod);
			}
			// Expose causes as provided arguments as well
			Throwable exToExpose = exception;
			while (exToExpose != null) {
				exceptions.add(exToExpose);
				Throwable cause = exToExpose.getCause();
				exToExpose = (cause != exToExpose ? cause : null);
			}
			Object[] arguments = new Object[exceptions.size() + 1];
			exceptions.toArray(arguments);  // efficient arraycopy call in ArrayList
			arguments[arguments.length - 1] = handlerMethod;
			exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer, arguments);
		}
		catch (Throwable invocationEx) {
			// Any other than the original exception (or a cause) is unintended here,
			// probably an accident (e.g. failed assertion or the like).
			if (!exceptions.contains(invocationEx) && logger.isWarnEnabled()) {
				logger.warn("Failure in @ExceptionHandler " + exceptionHandlerMethod, invocationEx);
			}
			// Continue with default processing of the original exception...
			return null;
		}

		if (mavContainer.isRequestHandled()) {
			return new ModelAndView();
		}
		else {
			ModelMap model = mavContainer.getModel();
			HttpStatusCode status = mavContainer.getStatus();
			ModelAndView mav = new ModelAndView(mavContainer.getViewName(), model, status);
			mav.setViewName(mavContainer.getViewName());
			if (!mavContainer.isViewReference()) {
				mav.setView((View) mavContainer.getView());
			}
			if (model instanceof RedirectAttributes) {
				Map<String, ?> flashAttributes = ((RedirectAttributes) model).getFlashAttributes();
				RequestContextUtils.getOutputFlashMap(request).putAll(flashAttributes);
			}
			return mav;
		}
	}

	/**
	 * Find an {@code @ExceptionHandler} method for the given exception. The default
	 * implementation searches methods in the class hierarchy of the controller first
	 * and if not found, it continues searching for additional {@code @ExceptionHandler}
	 * methods assuming some {@linkplain ControllerAdvice @ControllerAdvice}
	 * Spring-managed beans were detected.
	 * @param handlerMethod the method where the exception was raised (may be {@code null})
	 * @param exception the raised exception
	 * @return a method to handle the exception, or {@code null} if none
	 */
	@Nullable
	protected ServletInvocableHandlerMethod getExceptionHandlerMethod(
			@Nullable HandlerMethod handlerMethod, Exception exception) {

		Class<?> handlerType = null;

		if (handlerMethod != null) {
			// Local exception handler methods on the controller class itself.
			// To be invoked through the proxy, even in case of an interface-based proxy.
			handlerType = handlerMethod.getBeanType();
			ExceptionHandlerMethodResolver resolver = this.exceptionHandlerCache.computeIfAbsent(
					handlerType, ExceptionHandlerMethodResolver::new);
			Method method = resolver.resolveMethod(exception);
			if (method != null) {
				return new ServletInvocableHandlerMethod(handlerMethod.getBean(), method, this.applicationContext);
			}
			// For advice applicability check below (involving base packages, assignable types
			// and annotation presence), use target class instead of interface-based proxy.
			if (Proxy.isProxyClass(handlerType)) {
				handlerType = AopUtils.getTargetClass(handlerMethod.getBean());
			}
		}

		for (Map.Entry<ControllerAdviceBean, ExceptionHandlerMethodResolver> entry : this.exceptionHandlerAdviceCache.entrySet()) {
			ControllerAdviceBean advice = entry.getKey();
			if (advice.isApplicableToBeanType(handlerType)) {
				ExceptionHandlerMethodResolver resolver = entry.getValue();
				Method method = resolver.resolveMethod(exception);
				if (method != null) {
					return new ServletInvocableHandlerMethod(advice.resolveBean(), method, this.applicationContext);
				}
			}
		}

		return null;
	}

}

相关信息

spring 源码目录

相关文章

spring AbstractMappingJacksonResponseBodyAdvice 源码

spring AbstractMessageConverterMethodArgumentResolver 源码

spring AbstractMessageConverterMethodProcessor 源码

spring AsyncTaskMethodReturnValueHandler 源码

spring CallableMethodReturnValueHandler 源码

spring ContinuationHandlerMethodArgumentResolver 源码

spring DeferredResultMethodReturnValueHandler 源码

spring ExtendedServletRequestDataBinder 源码

spring HttpEntityMethodProcessor 源码

spring HttpHeadersReturnValueHandler 源码

0  赞