Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 ex.fileupload.spring; import java.io.ByteArrayInputStream; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.io.OutputStream; import java.io.UnsupportedEncodingException; import java.util.Map; import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileItemHeaders; import org.apache.commons.fileupload.FileItemHeadersSupport; import org.apache.commons.fileupload.ParameterParser; /** * * <p> * Important Note: This src is modifed version of * {@link org.apache.commons.fileupload.disk.DiskFileItem} to make it work under * GAE using Spring. * * <p> * All the File related codes are removed. For more info please check * {@link org.apache.commons.fileupload.disk.DiskFileItem} * * <p> * The class is an implementation of the * {@link org.apache.commons.fileupload.FileItem FileItem} interface. * * @author kernel164 */ public class GFileItem implements FileItem, FileItemHeadersSupport { // ----------------------------------------------------- Manifest constants private static final long serialVersionUID = -8090661404150222661L; /** * 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"; // ----------------------------------------------------------- Data members /** * 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 final String contentType; /** * Whether or not this item is a simple form field. */ private boolean isFormField; /** * The original filename in the user's filesystem. */ private final String fileName; /** * Cached contents of the file. */ private byte[] cachedContent; /** * Output stream for this item. */ private transient GOutputStream dfos; /** * The threshold above which uploads will be stored on disk. */ private int sizeThreshold; /** * The file items headers. */ private FileItemHeaders headers; // ----------------------------------------------------------- Constructors /** * Constructs a new <code>GFileItem</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. (sizeThresold will always be equal to file upload * limit) */ public GFileItem(String fieldName, String contentType, boolean isFormField, String fileName, int sizeThreshold) { this.fieldName = fieldName; this.contentType = contentType; this.isFormField = isFormField; this.fileName = fileName; this.sizeThreshold = sizeThreshold; } // ------------------------------- 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. * * @throws IOException * if an error occurs. */ public InputStream getInputStream() throws IOException { 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. */ @SuppressWarnings("unchecked") public String getCharSet() { ParameterParser parser = new ParameterParser(); parser.setLowerCaseNames(true); // Parameter parser can handle null input Map<String, String> params = parser.parse(getContentType(), ';'); return 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 true; } /** * Returns the size of the file. * * @return The size of the file, in bytes. */ public long getSize() { if (cachedContent != null) { return cachedContent.length; } else { return dfos.getData().length; } } /** * Returns the contents of the file as an array of bytes. * * @return The contents of the file as an array of bytes. */ public byte[] get() { if (cachedContent == null) { cachedContent = dfos.getData(); } return cachedContent; } /** * 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. * * @throws 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); } } /** * This method is not supported. * * @param file * The <code>File</code> into which the uploaded item should be * stored. */ public void write(File file) { throw new UnsupportedOperationException("Not possible in GAE."); } /** * Does nothing. */ public void delete() { // As all the data are in Heap, it will be garbage collected. } /** * 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} of the file. * * @return An {@link java.io.OutputStream OutputStream} of the file. * * @throws IOException * if an error occurs. */ public OutputStream getOutputStream() throws IOException { if (dfos == null) { dfos = new GOutputStream(sizeThreshold); } return dfos; } // -------------------------------------------------------- Private methods /** * Returns a string representation of this object. * * @return a string representation of this object. */ @Override public String toString() { return "name=" + this.getName() + ", size=" + this.getSize() + "bytes, " + "isFormField=" + isFormField() + ", FieldName=" + this.getFieldName(); } // -------------------------------------------------- Serialization methods /** * Writes the state of this object during serialization. * * @param out * The stream to which the state should be written. * * @throws IOException * if an error occurs. */ private void writeObject(ObjectOutputStream out) throws IOException { // Read the data cachedContent = get(); // write out values out.defaultWriteObject(); } /** * Reads the state of this object during deserialization. * * @param in * The stream from which the state should be read. * * @throws IOException * if an error occurs. * @throws ClassNotFoundException * if class cannot be found. */ private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException { // read values in.defaultReadObject(); OutputStream output = getOutputStream(); if (cachedContent != null) { output.write(cachedContent); } output.close(); cachedContent = null; } /** * Returns the file item headers. * * @return The file items headers. */ public FileItemHeaders getHeaders() { return headers; } /** * Sets the file item headers. * * @param pHeaders * The file items headers. */ public void setHeaders(FileItemHeaders pHeaders) { headers = pHeaders; } }