Java tutorial
/* * Copyright (c) 2008-2019 The Aspectran Project * * 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 com.aspectran.web.support.multipart.commons; import com.aspectran.core.activity.request.FileParameter; import com.aspectran.core.util.FilenameUtils; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItem; import java.io.ByteArrayInputStream; import java.io.File; import java.io.IOException; import java.io.InputStream; /** * This class represents a file item that was received within * a multipart/form-data POST request. * * <p>Created: 2008. 04. 11 PM 8:55:25</p> */ public class CommonsMultipartFileParameter extends FileParameter { private FileItem fileItem; private long fileSize; /** * Create an instance wrapping the given FileItem. * * @param fileItem the FileItem to wrap */ public CommonsMultipartFileParameter(FileItem fileItem) { this.fileItem = fileItem; this.fileSize = fileItem.getSize(); } @Override public File getFile() { if (fileItem instanceof DiskFileItem) { return ((DiskFileItem) fileItem).getStoreLocation(); } else { return null; } } /** * Gets the content type of the data being uploaded. This is never null, and * defaults to "content/unknown" when the mime type of the data couldn't be * determined and was not set manually. * * @return the content type */ @Override public String getContentType() { return fileItem.getContentType(); } /** * Returns the file name that was uploaded in the multipart form. * * @return the file name */ @Override public String getFileName() { return getCanonicalName(fileItem.getName()); } /** * Returns the file size that was uploaded in the multipart form. * * @return the file size */ @Override public long getFileSize() { return fileSize; } /** * Return an InputStream to read the contents of the file from. * * @return the contents of the file as stream, or an empty stream if empty * @throws IOException in case of access errors (if the temporary store fails) */ @Override public InputStream getInputStream() throws IOException { InputStream inputStream = fileItem.getInputStream(); return (inputStream != null ? inputStream : new ByteArrayInputStream(new byte[0])); } /** * Return an byte array to read the contents of the file from. * * @return the byte array */ @Override public byte[] getBytes() { byte[] bytes = fileItem.get(); return (bytes != null ? bytes : new byte[0]); } /** * Save an uploaded file as a given destination file. * * @param destFile the destination file * @param overwrite whether to overwrite if it already exists * @return a saved file * @throws IOException if an I/O error has occurred */ @Override public File saveAs(File destFile, boolean overwrite) throws IOException { if (destFile == null) { throw new IllegalArgumentException("destFile can not be null"); } validateFile(); try { destFile = determineDestinationFile(destFile, overwrite); fileItem.write(destFile); } catch (FileUploadException e) { throw new IllegalStateException(e.getMessage()); } catch (Exception e) { throw new IOException("Could not save as file " + destFile, e); } setSavedFile(destFile); return destFile; } @Override public File renameTo(File destFile, boolean overwrite) throws IOException { File file = getFile(); if (file == null) { throw new IllegalStateException("The uploaded temporary file does not exist"); } if (destFile == null) { throw new IllegalArgumentException("destFile can not be null"); } validateFile(); return super.renameTo(destFile, overwrite); } /** * Deletes the underlying Commons FileItem instances. */ @Override public void delete() { fileItem.delete(); } @Override public void release() { if (fileItem != null) { fileItem = null; } releaseSavedFile(); } /** * Returns the canonical name of the given filename. * * @param filename the given filename * @return the canonical name of the given filename */ private String getCanonicalName(String filename) { return FilenameUtils.getName(filename); } private void validateFile() { if (!isAvailable()) { throw new IllegalStateException("File has been moved - cannot be read again"); } } /** * Determine whether the multipart content is still available. * If a temporary file has been moved, the content is no longer available. * * @return true, if the multipart content is still available */ private boolean isAvailable() { // If in memory, it's available. if (fileItem.isInMemory()) { return true; } // Check actual existence of temporary file. if (fileItem instanceof DiskFileItem) { return ((DiskFileItem) fileItem).getStoreLocation().exists(); } // Check whether current file size is different than original one. return (fileItem.getSize() == fileSize); } /** * Return a description for the storage location of the multipart content. * Tries to be as specific as possible: mentions the file location in case * of a temporary file. * * @return a description for the storage location of the multipart content */ public String getStorageDescription() { if (fileItem.isInMemory()) { return "in memory"; } else if (this.fileItem instanceof DiskFileItem) { return "at [" + ((DiskFileItem) this.fileItem).getStoreLocation().getAbsolutePath() + "]"; } else { return "on disk"; } } }