SPR-5624 - A default HandlerExceptionResolver that resolves standard Spring exceptions

Author: poutsma

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/DispatcherServlet.java

@@ -13,6 +13,8 @@ org.springframework.web.servlet.HandlerAdapter=org.springframework.web.servlet.m
 	org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,\
 	org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter
 
+org.springframework.web.servlet.HandlerExceptionResolver=org.springframework.web.servlet.handler.DefaultHandlerExceptionResolver
+
 org.springframework.web.servlet.RequestToViewNameTranslator=org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator
 
 org.springframework.web.servlet.ViewResolver=org.springframework.web.servlet.view.InternalResourceViewResolver

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/DispatcherServlet.properties

@@ -0,0 +1,190 @@
+/*
+ * Copyright 2002-2009 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
+ *
+ *      http://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.handler;
+
+import java.util.Set;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.core.Ordered;
+import org.springframework.web.servlet.HandlerExceptionResolver;
+import org.springframework.web.servlet.ModelAndView;
+
+/**
+ * Abstract base class for {@link HandlerExceptionResolver} implementations. <p>Provides a set of mapped handlers that
+ * the resolver should map to, and the {@link Ordered} implementation.
+ *
+ * @author Arjen Poutsma
+ * @since 3.0
+ */
+public abstract class AbstractHandlerExceptionResolver implements HandlerExceptionResolver, Ordered {
+
+	/** Logger available to subclasses */
+	protected final Log logger = LogFactory.getLog(getClass());
+
+	private int order = Ordered.LOWEST_PRECEDENCE;
+
+	private Set mappedHandlers;
+
+	private Class[] mappedHandlerClasses;
+
+	private Log warnLogger;
+
+	public void setOrder(int order) {
+		this.order = order;
+	}
+
+	public int getOrder() {
+		return this.order;
+	}
+
+	/**
+	 * Specify the set of handlers that this exception resolver should apply to. The exception mappings and the default
+	 * error view will only apply to the specified handlers. <p>If no handlers and handler classes are set, the exception
+	 * mappings and the default error view will apply to all handlers. This means that a specified default error view will
+	 * be used as fallback for all exceptions; any further HandlerExceptionResolvers in the chain will be ignored in this
+	 * case.
+	 */
+	public void setMappedHandlers(Set mappedHandlers) {
+		this.mappedHandlers = mappedHandlers;
+	}
+
+	/**
+	 * Specify the set of classes that this exception resolver should apply to. The exception mappings and the default
+	 * error view will only apply to handlers of the specified type; the specified types may be interfaces and superclasses
+	 * of handlers as well. <p>If no handlers and handler classes are set, the exception mappings and the default error
+	 * view will apply to all handlers. This means that a specified default error view will be used as fallback for all
+	 * exceptions; any further HandlerExceptionResolvers in the chain will be ignored in this case.
+	 */
+	public void setMappedHandlerClasses(Class[] mappedHandlerClasses) {
+		this.mappedHandlerClasses = mappedHandlerClasses;
+	}
+
+	/**
+	 * Set the log category for warn logging. The name will be passed to the underlying logger implementation through
+	 * Commons Logging, getting interpreted as log category according to the logger's configuration. <p>Default is no warn
+	 * logging. Specify this setting to activate warn logging into a specific category. Alternatively, override the {@link
+	 * #logException} method for custom logging.
+	 *
+	 * @see org.apache.commons.logging.LogFactory#getLog(String)
+	 * @see org.apache.log4j.Logger#getLogger(String)
+	 * @see java.util.logging.Logger#getLogger(String)
+	 */
+	public void setWarnLogCategory(String loggerName) {
+		this.warnLogger = LogFactory.getLog(loggerName);
+	}
+
+	/**
+	 * Checks whether this resolver is supposed to apply (i.e. the handler matches in case of "mappedHandlers" having been
+	 * specified), then delegates to the {@link #doResolveException} template method.
+	 */
+	public ModelAndView resolveException(HttpServletRequest request,
+			HttpServletResponse response,
+			Object handler,
+			Exception ex) {
+
+		if (shouldApplyTo(request, handler)) {
+			// Log exception, both at debug log level and at warn level, if desired.
+			if (logger.isDebugEnabled()) {
+				logger.debug("Resolving exception from handler [" + handler + "]: " + ex);
+			}
+			logException(ex, request);
+			return doResolveException(request, response, handler, ex);
+		}
+		else {
+			return null;
+		}
+	}
+
+	/**
+	 * Check whether this resolver is supposed to apply to the given handler. <p>The default implementation checks against
+	 * the specified mapped handlers and handler classes, if any.
+	 *
+	 * @param request current HTTP request
+	 * @param handler the executed handler, or <code>null</code> if none chosen at the time of the exception (for example,
+	 * if multipart resolution failed)
+	 * @return whether this resolved should proceed with resolving the exception for the given request and handler
+	 * @see #setMappedHandlers
+	 * @see #setMappedHandlerClasses
+	 */
+	protected boolean shouldApplyTo(HttpServletRequest request, Object handler) {
+		if (handler != null) {
+			if (this.mappedHandlers != null && this.mappedHandlers.contains(handler)) {
+				return true;
+			}
+			if (this.mappedHandlerClasses != null) {
+				for (Class handlerClass : this.mappedHandlerClasses) {
+					if (handlerClass.isInstance(handler)) {
+						return true;
+					}
+				}
+			}
+		}
+		// Else only apply if there are no explicit handler mappings.
+		return (this.mappedHandlers == null && this.mappedHandlerClasses == null);
+	}
+
+	/**
+	 * Log the given exception at warn level, provided that warn logging has been activated through the {@link
+	 * #setWarnLogCategory "warnLogCategory"} property. <p>Calls {@link #buildLogMessage} in order to determine the
+	 * concrete message to log. Always passes the full exception to the logger.
+	 *
+	 * @param ex the exception that got thrown during handler execution
+	 * @param request current HTTP request (useful for obtaining metadata)
+	 * @see #setWarnLogCategory
+	 * @see #buildLogMessage
+	 * @see org.apache.commons.logging.Log#warn(Object, Throwable)
+	 */
+	protected void logException(Exception ex, HttpServletRequest request) {
+		if (this.warnLogger != null && this.warnLogger.isWarnEnabled()) {
+			this.warnLogger.warn(buildLogMessage(ex, request), ex);
+		}
+	}
+
+	/**
+	 * Build a log message for the given exception, occured during processing the given request.
+	 *
+	 * @param ex the exception that got thrown during handler execution
+	 * @param request current HTTP request (useful for obtaining metadata)
+	 * @return the log message to use
+	 */
+	protected String buildLogMessage(Exception ex, HttpServletRequest request) {
+		return "Handler execution resulted in exception";
+	}
+
+	/**
+	 * Actually resolve the given exception that got thrown during on handler execution, returning a ModelAndView that
+	 * represents a specific error page if appropriate. <p>May be overridden in subclasses, in order to apply specific
+	 * exception checks. Note that this template method will be invoked <i>after</i> checking whether this resolved applies
+	 * ("mappedHandlers" etc), so an implementation may simply proceed with its actual exception handling.
+	 *
+	 * @param request current HTTP request
+	 * @param response current HTTP response
+	 * @param handler the executed handler, or <code>null</code> if none chosen at the time of the exception (for example,
+	 * if multipart resolution failed)
+	 * @param ex the exception that got thrown during handler execution
+	 * @return a corresponding ModelAndView to forward to, or <code>null</code> for default processing
+	 */
+	protected abstract ModelAndView doResolveException(HttpServletRequest request,
+			HttpServletResponse response,
+			Object handler,
+			Exception ex);
+
+}