Java tutorial
/* * Copyright 2001-2004 The Apache Software Foundation * * 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.mob.forum.util.legacy.commons.fileupload.disk; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.ByteArrayInputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.UnsupportedEncodingException; import java.util.Map; import org.apache.commons.io.FileCleaner; import org.apache.commons.io.output.DeferredFileOutputStream; import com.mob.forum.util.legacy.commons.fileupload.FileItem; import com.mob.forum.util.legacy.commons.fileupload.FileUploadException; import com.mob.forum.util.legacy.commons.fileupload.ParameterParser; /** * <p> The default implementation of the * {@link org.apache.commons.fileupload.FileItem FileItem} interface. * * <p> After retrieving an instance of this class from a {@link * org.apache.commons.fileupload.DiskFileUpload DiskFileUpload} instance (see * {@link org.apache.commons.fileupload.DiskFileUpload * #parseRequest(javax.servlet.http.HttpServletRequest)}), you may * either request all contents of file at once using {@link #get()} or * request an {@link java.io.InputStream InputStream} with * {@link #getInputStream()} and process the file without attempting to load * it into memory, which may come handy with large files. * * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a> * @author <a href="mailto:sean@informage.net">Sean Legassick</a> * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a> * @author <a href="mailto:jmcnally@apache.org">John McNally</a> * @author <a href="mailto:martinc@apache.org">Martin Cooper</a> * @author Sean C. Sullivan * * @since FileUpload 1.1 * * @version $Id: DiskFileItem.java,v 1.3 2005/07/26 03:05:02 rafaelsteil Exp $ */ public class DiskFileItem implements FileItem { // ----------------------------------------------------- Manifest constants /** * Default content charset to be used when no explicit charset * parameter is provided by the sender. Media subtypes of the * "text" type are defined to have a default charset value of * "ISO-8859-1" when received via HTTP. */ public static final String DEFAULT_CHARSET = "ISO-8859-1"; /** * Size of buffer to use when writing an item to disk. */ private static final int WRITE_BUFFER_SIZE = 2048; // ----------------------------------------------------------- Data members /** * Counter used in unique identifier generation. */ private static int counter = 0; /** * The name of the form field as provided by the browser. */ private String fieldName; /** * The content type passed by the browser, or <code>null</code> if * not defined. */ private String contentType; /** * Whether or not this item is a simple form field. */ private boolean isFormField; /** * The original filename in the user's filesystem. */ private String fileName; /** * The threshold above which uploads will be stored on disk. */ private int sizeThreshold; /** * The directory in which uploaded files will be stored, if stored on disk. */ private File repository; /** * Cached contents of the file. */ private byte[] cachedContent; /** * Output stream for this item. */ private DeferredFileOutputStream dfos; // ----------------------------------------------------------- Constructors /** * Constructs a new <code>DiskFileItem</code> instance. * * @param fieldName The name of the form field. * @param contentType The content type passed by the browser or * <code>null</code> if not specified. * @param isFormField Whether or not this item is a plain form field, as * opposed to a file upload. * @param fileName The original filename in the user's filesystem, or * <code>null</code> if not specified. * @param sizeThreshold The threshold, in bytes, below which items will be * retained in memory and above which they will be * stored as a file. * @param repository The data repository, which is the directory in * which files will be created, should the item size * exceed the threshold. */ public DiskFileItem(String fieldName, String contentType, boolean isFormField, String fileName, int sizeThreshold, File repository) { this.fieldName = fieldName; this.contentType = contentType; this.isFormField = isFormField; this.fileName = fileName; this.sizeThreshold = sizeThreshold; this.repository = repository; } // ------------------------------- Methods from javax.activation.DataSource /** * Returns an {@link java.io.InputStream InputStream} that can be * used to retrieve the contents of the file. * * @return An {@link java.io.InputStream InputStream} that can be * used to retrieve the contents of the file. * * @exception IOException if an error occurs. */ public InputStream getInputStream() throws IOException { if (!dfos.isInMemory()) { return new FileInputStream(dfos.getFile()); } if (cachedContent == null) { cachedContent = dfos.getData(); } return new ByteArrayInputStream(cachedContent); } /** * Returns the content type passed by the agent or <code>null</code> if * not defined. * * @return The content type passed by the agent or <code>null</code> if * not defined. */ public String getContentType() { return contentType; } /** * Returns the content charset passed by the agent or <code>null</code> if * not defined. * * @return The content charset passed by the agent or <code>null</code> if * not defined. */ public String getCharSet() { ParameterParser parser = new ParameterParser(); parser.setLowerCaseNames(true); // Parameter parser can handle null input Map params = parser.parse(getContentType(), ';'); return (String) params.get("charset"); } /** * Returns the original filename in the client's filesystem. * * @return The original filename in the client's filesystem. */ public String getName() { return fileName; } // ------------------------------------------------------- FileItem methods /** * Provides a hint as to whether or not the file contents will be read * from memory. * * @return <code>true</code> if the file contents will be read * from memory; <code>false</code> otherwise. */ public boolean isInMemory() { return (dfos.isInMemory()); } /** * Returns the size of the file. * * @return The size of the file, in bytes. */ public long getSize() { if (cachedContent != null) { return cachedContent.length; } else if (dfos.isInMemory()) { return dfos.getData().length; } else { return dfos.getFile().length(); } } /** * Returns the contents of the file as an array of bytes. If the * contents of the file were not yet cached in memory, they will be * loaded from the disk storage and cached. * * @return The contents of the file as an array of bytes. */ public byte[] get() { if (dfos.isInMemory()) { if (cachedContent == null) { cachedContent = dfos.getData(); } return cachedContent; } byte[] fileData = new byte[(int) getSize()]; FileInputStream fis = null; try { fis = new FileInputStream(dfos.getFile()); fis.read(fileData); } catch (IOException e) { fileData = null; } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { // ignore } } } return fileData; } /** * Returns the contents of the file as a String, using the specified * encoding. This method uses {@link #get()} to retrieve the * contents of the file. * * @param charset The charset to use. * * @return The contents of the file, as a string. * * @exception UnsupportedEncodingException if the requested character * encoding is not available. */ public String getString(final String charset) throws UnsupportedEncodingException { return new String(get(), charset); } /** * Returns the contents of the file as a String, using the default * character encoding. This method uses {@link #get()} to retrieve the * contents of the file. * * @return The contents of the file, as a string. * * @todo Consider making this method throw UnsupportedEncodingException. */ public String getString() { byte[] rawdata = get(); String charset = getCharSet(); if (charset == null) { charset = DEFAULT_CHARSET; } try { return new String(rawdata, charset); } catch (UnsupportedEncodingException e) { return new String(rawdata); } } /** * A convenience method to write an uploaded item to disk. The client code * is not concerned with whether or not the item is stored in memory, or on * disk in a temporary location. They just want to write the uploaded item * to a file. * <p> * This implementation first attempts to rename the uploaded item to the * specified destination file, if the item was originally written to disk. * Otherwise, the data will be copied to the specified file. * <p> * This method is only guaranteed to work <em>once</em>, the first time it * is invoked for a particular item. This is because, in the event that the * method renames a temporary file, that file will no longer be available * to copy or rename again at a later time. * * @param file The <code>File</code> into which the uploaded item should * be stored. * * @exception Exception if an error occurs. */ public void write(File file) throws Exception { if (isInMemory()) { FileOutputStream fout = null; try { fout = new FileOutputStream(file); fout.write(get()); } finally { if (fout != null) { fout.close(); } } } else { File outputFile = getStoreLocation(); if (outputFile != null) { /* * The uploaded file is being stored on disk * in a temporary location so move it to the * desired file. */ if (!outputFile.renameTo(file)) { BufferedInputStream in = null; BufferedOutputStream out = null; try { in = new BufferedInputStream(new FileInputStream(outputFile)); out = new BufferedOutputStream(new FileOutputStream(file)); byte[] bytes = new byte[WRITE_BUFFER_SIZE]; int s = 0; while ((s = in.read(bytes)) != -1) { out.write(bytes, 0, s); } } finally { if (in != null) { try { in.close(); } catch (IOException e) { // ignore } } if (out != null) { try { out.close(); } catch (IOException e) { // ignore } } } } } else { /* * For whatever reason we cannot write the * file to disk. */ throw new FileUploadException("Cannot write uploaded file to disk!"); } } } /** * Deletes the underlying storage for a file item, including deleting any * associated temporary disk file. Although this storage will be deleted * automatically when the <code>FileItem</code> instance is garbage * collected, this method can be used to ensure that this is done at an * earlier time, thus preserving system resources. */ public void delete() { cachedContent = null; File outputFile = getStoreLocation(); if (outputFile != null && outputFile.exists()) { outputFile.delete(); } } /** * Returns the name of the field in the multipart form corresponding to * this file item. * * @return The name of the form field. * * @see #setFieldName(java.lang.String) * */ public String getFieldName() { return fieldName; } /** * Sets the field name used to reference this file item. * * @param fieldName The name of the form field. * * @see #getFieldName() * */ public void setFieldName(String fieldName) { this.fieldName = fieldName; } /** * Determines whether or not a <code>FileItem</code> instance represents * a simple form field. * * @return <code>true</code> if the instance represents a simple form * field; <code>false</code> if it represents an uploaded file. * * @see #setFormField(boolean) * */ public boolean isFormField() { return isFormField; } /** * Specifies whether or not a <code>FileItem</code> instance represents * a simple form field. * * @param state <code>true</code> if the instance represents a simple form * field; <code>false</code> if it represents an uploaded file. * * @see #isFormField() * */ public void setFormField(boolean state) { isFormField = state; } /** * Returns an {@link java.io.OutputStream OutputStream} that can * be used for storing the contents of the file. * * @return An {@link java.io.OutputStream OutputStream} that can be used * for storing the contensts of the file. * * @exception IOException if an error occurs. */ public OutputStream getOutputStream() throws IOException { if (dfos == null) { File outputFile = getTempFile(); dfos = new DeferredFileOutputStream(sizeThreshold, outputFile); } return dfos; } // --------------------------------------------------------- Public methods /** * Returns the {@link java.io.File} object for the <code>FileItem</code>'s * data's temporary location on the disk. Note that for * <code>FileItem</code>s that have their data stored in memory, * this method will return <code>null</code>. When handling large * files, you can use {@link java.io.File#renameTo(java.io.File)} to * move the file to new location without copying the data, if the * source and destination locations reside within the same logical * volume. * * @return The data file, or <code>null</code> if the data is stored in * memory. */ public File getStoreLocation() { return dfos.getFile(); } // ------------------------------------------------------ Protected methods /** * Removes the file contents from the temporary storage. */ protected void finalize() { File outputFile = dfos.getFile(); if (outputFile != null && outputFile.exists()) { outputFile.delete(); } } /** * Creates and returns a {@link java.io.File File} representing a uniquely * named temporary file in the configured repository path. The lifetime of * the file is tied to the lifetime of the <code>FileItem</code> instance; * the file will be deleted when the instance is garbage collected. * * @return The {@link java.io.File File} to be used for temporary storage. */ protected File getTempFile() { File tempDir = repository; if (tempDir == null) { tempDir = new File(System.getProperty("java.io.tmpdir")); } String fileName = "upload_" + getUniqueId() + ".tmp"; File f = new File(tempDir, fileName); FileCleaner.track(f, this); return f; } // -------------------------------------------------------- Private methods /** * Returns an identifier that is unique within the class loader used to * load this class, but does not have random-like apearance. * * @return A String with the non-random looking instance identifier. */ private static String getUniqueId() { int current; synchronized (DiskFileItem.class) { current = counter++; } String id = Integer.toString(current); // If you manage to get more than 100 million of ids, you'll // start getting ids longer than 8 characters. if (current < 100000000) { id = ("00000000" + id).substring(id.length()); } return id; } public String toString() { return "name=" + this.getName() + ", StoreLocation=" + String.valueOf(this.getStoreLocation()) + ", size=" + this.getSize() + "bytes, " + "isFormField=" + isFormField() + ", FieldName=" + this.getFieldName(); } }