cn.clxy.studio.common.web.multipart.GMultipartResolver.java Source code

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Here is the source code for cn.clxy.studio.common.web.multipart.GMultipartResolver.java

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/*
 * Copyright 2002-2008 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 cn.clxy.studio.common.web.multipart;

import org.apache.commons.fileupload.*;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
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 javax.servlet.http.HttpServletRequest;
import java.util.List;

/**
 * <p>This src is modified from Spring 3.0 CommonsMultipartResolver.java and renamed to GMultipartResolver
 * to make it work in GAE.
 *
 * <p>Servlet-based {@link org.springframework.web.multipart.MultipartResolver} implementation for <a
 * href="http://jakarta.apache.org/commons/fileupload">Jakarta Commons FileUpload</a> 1.2 or above.
 *
 * <p>
 * Provides "maxUploadSize" and "defaultEncoding" settings as bean properties
 * (inherited from {@link GFileUploadSupport}).
 *
 * See corresponding ServletFileUpload / GFileItemFactory properties ("sizeMax", "sizeThreshold", "headerEncoding") for details in
 * terms of defaults and accepted values.
 * </p>
 *
 * @author kernel164
 */
public class GMultipartResolver extends GFileUploadSupport implements MultipartResolver {
    private boolean resolveLazily = false;

    /**
     * Set whether to resolve the multipart request lazily at the time of file or parameter access.
     * <p>
     * Default is "false", resolving the multipart elements immediately, throwing corresponding
     * exceptions at the time of the {@link #resolveMultipart} call. Switch this to "true" for lazy
     * multipart parsing, throwing parse exceptions once the application attempts to obtain
     * multipart files or parameters.
     */
    public void setResolveLazily(boolean resolveLazily) {
        this.resolveLazily = resolveLazily;
    }

    /**
     * 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
     */
    @Override
    protected FileUpload newFileUpload(FileItemFactory fileItemFactory) {
        return new ServletFileUpload(fileItemFactory);
    }

    /**
     * Returns true if the request has multipart.
     */
    public boolean isMultipart(HttpServletRequest request) {
        return (request != null && ServletFileUpload.isMultipartContent(request));
    }

    /**
     * Resolves multipart request.
     */
    public MultipartHttpServletRequest resolveMultipart(final HttpServletRequest request)
            throws MultipartException {
        if (this.resolveLazily) {
            return new DefaultMultipartHttpServletRequest(request) {
                @Override
                protected void initializeMultipart() {
                    MultipartParsingResult parsingResult = parseRequest(request);
                    setMultipartFiles(parsingResult.getMultipartFiles());
                    setMultipartParameters(parsingResult.getMultipartParameters());
                }
            };
        } else {
            MultipartParsingResult parsingResult = parseRequest(request);

            return new DefaultMultipartHttpServletRequest(request, parsingResult.getMultipartFiles(),
                    parsingResult.getMultipartParameters(), parsingResult.getMultipartParameterContentTypes());
        }
    }

    /**
     * Parse the given servlet request, resolving its multipart elements.
     *
     * @param request the request to parse
     * @return the parsing result
     * @throws MultipartException if multipart resolution failed.
     */
    protected MultipartParsingResult parseRequest(HttpServletRequest request) throws MultipartException {
        String encoding = determineEncoding(request);
        FileUpload fileUpload = prepareFileUpload(encoding);
        try {
            List<FileItem> fileItems = ((ServletFileUpload) fileUpload).parseRequest(request);
            return parseFileItems(fileItems, encoding);
        } 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;
    }

    /**
     * Clean up multi part.
     */
    public void cleanupMultipart(MultipartHttpServletRequest request) {
        if (request != null) {
            try {
                cleanupFileItems(request.getFileMap().values());
            } catch (Throwable ex) {
                logger.warn("Failed to perform multipart cleanup for servlet request", ex);
            }
        }
    }
}