commonsmultipartresolver.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.multipart.commons;

import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.FileUpload;
import org.apache.commons.fileupload.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.servlet.ServletRequestContext;

import org.springframework.util.ClassUtils;
import org.springframework.web.context.ServletContextAware;
import org.springframework.web.multipart.MaxUploadSizeExceededException;
import org.springframework.web.multipart.MultipartException;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.multipart.MultipartResolver;
import org.springframework.web.multipart.support.DefaultMultipartHttpServletRequest;
import org.springframework.web.util.WebUtils;

/**
 * Servlet-based {@link org.springframework.web.multipart.MultipartResolver} implementation
 * for <a href="http://jakarta.apache.org/commons/fileupload">Jakarta Commons FileUpload</a>
 * 1.1 or above. Commons FileUpload 1.2 or above is recommended.
 *
 * <p>Provides "maxUploadSize", "maxInMemorySize" and "defaultEncoding" settings as
 * bean properties (inherited from {@link CommonsFileUploadSupport}). See corresponding
 * ServletFileUpload / DiskFileItemFactory properties ("sizeMax", "sizeThreshold",
 * "headerEncoding") for details in terms of defaults and accepted values.
 *
 * <p>Saves temporary files to the servlet container's temporary directory.
 * Needs to be initialized <i>either</i> by an application context <i>or</i>
 * via the constructor that takes a ServletContext (for standalone usage).
 *
 * <p><b>NOTE:</b> As of Spring 2.0, this multipart resolver requires
 * Commons FileUpload 1.1 or higher. The implementation does not use
 * any deprecated FileUpload 1.0 API anymore, to be compatible with future
 * Commons FileUpload releases.
 *
 * @author Trevor D. Cook
 * @author Juergen Hoeller
 * @since 29.09.2003
 * @see #CommonsMultipartResolver(ServletContext)
 * @see CommonsMultipartFile
 * @see org.springframework.web.portlet.multipart.PortletMultipartResolver
 * @see org.apache.commons.fileupload.servlet.ServletFileUpload
 * @see org.apache.commons.fileupload.disk.DiskFileItemFactory
 */
public class CommonsMultipartResolver extends CommonsFileUploadSupport
		implements MultipartResolver, ServletContextAware {

	private final boolean commonsFileUpload12Present =
			ClassUtils.hasMethod(ServletFileUpload.class, "isMultipartContent", new Class[] {HttpServletRequest.class});


	/**
	 * Constructor for use as bean. Determines the servlet container's
	 * temporary directory via the ServletContext passed in as through the
	 * ServletContextAware interface (typically by a WebApplicationContext).
	 * @see #setServletContext
	 * @see org.springframework.web.context.ServletContextAware
	 * @see org.springframework.web.context.WebApplicationContext
	 */
	public CommonsMultipartResolver() {
		super();
	}

	/**
	 * Constructor for standalone usage. Determines the servlet container's
	 * temporary directory via the given ServletContext.
	 * @param servletContext the ServletContext to use
	 */
	public CommonsMultipartResolver(ServletContext servletContext) {
		this();
		setServletContext(servletContext);
	}


	/**
	 * Initialize the underlying <code>org.apache.commons.fileupload.servlet.ServletFileUpload</code>
	 * instance. Can be overridden to use a custom subclass, e.g. for testing purposes.
	 * @param fileItemFactory the Commons FileItemFactory to use
	 * @return the new ServletFileUpload instance
	 */
	protected FileUpload newFileUpload(FileItemFactory fileItemFactory) {
		return new ServletFileUpload(fileItemFactory);
	}

	public void setServletContext(ServletContext servletContext) {
		if (!isUploadTempDirSpecified()) {
			getFileItemFactory().setRepository(WebUtils.getTempDir(servletContext));
		}
	}


	public boolean isMultipart(HttpServletRequest request) {
		if (commonsFileUpload12Present) {
			return ServletFileUpload.isMultipartContent(request);
		}
		else {
			return ServletFileUpload.isMultipartContent(new ServletRequestContext(request));
		}
	}

	public MultipartHttpServletRequest resolveMultipart(HttpServletRequest request) throws MultipartException {
		String encoding = determineEncoding(request);
		FileUpload fileUpload = prepareFileUpload(encoding);
		try {
			List fileItems = ((ServletFileUpload) fileUpload).parseRequest(request);
			MultipartParsingResult parsingResult = parseFileItems(fileItems, encoding);
			return new DefaultMultipartHttpServletRequest(
					request, parsingResult.getMultipartFiles(), parsingResult.getMultipartParameters());
		}
		catch (FileUploadBase.SizeLimitExceededException ex) {
			throw new MaxUploadSizeExceededException(fileUpload.getSizeMax(), ex);
		}
		catch (FileUploadException ex) {
			throw new MultipartException("Could not parse multipart servlet request", ex);
		}
	}

	/**
	 * Determine the encoding for the given request.
	 * Can be overridden in subclasses.
	 * <p>The default implementation checks the request encoding,
	 * falling back to the default encoding specified for this resolver.
	 * @param request current HTTP request
	 * @return the encoding for the request (never <code>null</code>)
	 * @see javax.servlet.ServletRequest#getCharacterEncoding
	 * @see #setDefaultEncoding
	 */
	protected String determineEncoding(HttpServletRequest request) {
		String encoding = request.getCharacterEncoding();
		if (encoding == null) {
			encoding = getDefaultEncoding();
		}
		return encoding;
	}

	public void cleanupMultipart(MultipartHttpServletRequest request) {
		cleanupFileItems(request.getFileMap().values());
	}

}