simplemappingexceptionresolver.java

spring api 源代码

/*
 * Copyright 2002-2007 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.Enumeration;
import java.util.Properties;
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;
import org.springframework.web.util.WebUtils;

/**
 * {@link org.springframework.web.servlet.HandlerExceptionResolver} implementation
 * that allows for mapping exception class names to view names, either for a
 * set of given handlers or for all handlers in the DispatcherServlet.
 *
 * <p>Error views are analogous to error page JSPs, but can be used with any
 * kind of exception including any checked one, with fine-granular mappings for
 * specific handlers.
 *
 * @author Juergen Hoeller
 * @since 22.11.2003
 * @see org.springframework.web.servlet.DispatcherServlet
 */
public class SimpleMappingExceptionResolver implements HandlerExceptionResolver, Ordered {

	/**
	 * The default name of the exception attribute: "exception".
	 */
	public static final String DEFAULT_EXCEPTION_ATTRIBUTE = "exception";


	/** Logger available to subclasses */
	protected final Log logger = LogFactory.getLog(getClass());

	private int order = Integer.MAX_VALUE;  // default: same as non-Ordered

	private Set mappedHandlers;

	private Class[] mappedHandlerClasses;

	private Log warnLogger;

	private Properties exceptionMappings;

	private String defaultErrorView;

	private Integer defaultStatusCode;

	private String exceptionAttribute = DEFAULT_EXCEPTION_ATTRIBUTE;


	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);
	}

	/**
	 * Set the mappings between exception class names and error view names.
	 * The exception class name can be a substring, with no wildcard support
	 * at present. A value of "ServletException" would match
	 * <code>javax.servlet.ServletException</code> and subclasses, for example.
	 * <p><b>NB:</b> Consider carefully how specific the pattern is, and whether
	 * to include package information (which isn't mandatory). For example,
	 * "Exception" will match nearly anything, and will probably hide other rules.
	 * "java.lang.Exception" would be correct if "Exception" was meant to define
	 * a rule for all checked exceptions. With more unusual exception names such
	 * as "BaseBusinessException" there's no need to use a FQN.
	 * <p>Follows the same matching algorithm as RuleBasedTransactionAttribute
	 * and RollbackRuleAttribute.
	 * @param mappings exception patterns (can also be fully qualified class names)
	 * as keys, and error view names as values
	 * @see org.springframework.transaction.interceptor.RuleBasedTransactionAttribute
	 * @see org.springframework.transaction.interceptor.RollbackRuleAttribute
	 */
	public void setExceptionMappings(Properties mappings) {
		this.exceptionMappings = mappings;
	}

	/**
	 * Set the name of the default error view.
	 * This view will be returned if no specific mapping was found.
	 * <p>Default is none.
	 */
	public void setDefaultErrorView(String defaultErrorView) {
		this.defaultErrorView = defaultErrorView;
	}

	/**
	 * Set the default HTTP status code that this exception resolver will apply
	 * if it resolves an error view.
	 * <p>Note that this error code will only get applied in case of a top-level
	 * request. It will not be set for an include request, since the HTTP status
	 * cannot be modified from within an include.
	 * <p>If not specified, no status code will be applied, either leaving this to
	 * the controller or view, or keeping the servlet engine's default of 200 (OK).
	 * @param defaultStatusCode HTTP status code value, for example
	 * 500 (SC_INTERNAL_SERVER_ERROR) or 404 (SC_NOT_FOUND)
	 * @see javax.servlet.http.HttpServletResponse#SC_INTERNAL_SERVER_ERROR
	 * @see javax.servlet.http.HttpServletResponse#SC_NOT_FOUND
	 */
	public void setDefaultStatusCode(int defaultStatusCode) {
		this.defaultStatusCode = new Integer(defaultStatusCode);
	}

	/**
	 * Set the name of the model attribute as which the exception should
	 * be exposed. Default is "exception".
	 * <p>This can be either set to a different attribute name or to
	 * <code>null</code> for not exposing an exception attribute at all.
	 * @see #DEFAULT_EXCEPTION_ATTRIBUTE
	 */
	public void setExceptionAttribute(String exceptionAttribute) {
		this.exceptionAttribute = exceptionAttribute;
	}


	/**
	 * 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)) {
			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 (int i = 0; i < this.mappedHandlerClasses.length; i++) {
					if (this.mappedHandlerClasses[i].isInstance(handler)) {
						return true;