Java tutorial
package imageencode; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import org.apache.commons.codec.binary.Base64; import org.w3c.dom.Element; public class ImageEncode { // private static final String BASE_64_FILE_SUFFIX = ".64"; // private static final int BLOCK_SIZE = 128; /** * A utility class to convert to and from base 64 encoding. * * @author <a href="mailto:russgold@httpunit.org">Russell Gold</a> **/ public static class Base64_ { final static String encodingChar = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; private void convert3To4(final char[] source, final int sourceIndex, final char[] target) { target[0] = (char) (source[sourceIndex] >>> 2); target[1] = (char) ((source[sourceIndex] & 0x03) << 4 | source[sourceIndex + 1] >>> 4); target[2] = (char) ((source[sourceIndex + 1] & 0x0f) << 2 | source[sourceIndex + 2] >>> 6); target[3] = (char) (source[sourceIndex + 2] & 0x3f); } private void convert4To3(final byte[] source, final byte[] target, final int targetIndex) { target[targetIndex] = (byte) (source[0] << 2 | source[1] >>> 4); target[targetIndex + 1] = (byte) ((source[1] & 0x0f) << 4 | source[2] >>> 2); target[targetIndex + 2] = (byte) ((source[2] & 0x03) << 6 | source[3]); } /** * Returns the plaintext equivalent of a base 64-encoded string. * * @param source * a base 64 string (which must have a multiple of 4 * characters) */ public String decode(final String source) { if (source.length() % 4 != 0) { throw new RuntimeException("valid Base64 codes have a multiple of 4 characters"); } final int numGroups = source.length() / 4; final int numExtraBytes = source.endsWith("==") ? 2 : source.endsWith("=") ? 1 : 0; final byte[] targetBytes = new byte[3 * numGroups]; final byte[] sourceBytes = new byte[4]; for (int group = 0; group < numGroups; group++) { for (int i = 0; i < sourceBytes.length; i++) { sourceBytes[i] = (byte) Math.max(0, encodingChar.indexOf(source.charAt(4 * group + i))); } convert4To3(sourceBytes, targetBytes, group * 3); } return new String(targetBytes, 0, targetBytes.length - numExtraBytes); } /** * Returns the base 64 encoded equivalent of a supplied string. * * @param source * the string to encode */ public String encode(final String source) { final char[] sourceBytes = getPaddedBytes(source); final int numGroups = (sourceBytes.length + 2) / 3; final char[] targetBytes = new char[4]; final char[] target = new char[4 * numGroups]; for (int group = 0; group < numGroups; group++) { convert3To4(sourceBytes, group * 3, targetBytes); for (int i = 0; i < targetBytes.length; i++) { target[i + 4 * group] = encodingChar.charAt(targetBytes[i]); } } final int numPadBytes = sourceBytes.length - source.length(); for (int i = target.length - numPadBytes; i < target.length; i++) { target[i] = '='; } return new String(target); } private char[] getPaddedBytes(final String source) { final char[] converted = source.toCharArray(); final int requiredLength = 3 * ((converted.length + 2) / 3); final char[] result = new char[requiredLength]; System.arraycopy(converted, 0, result, 0, converted.length); return result; } } public static byte[] getBytesFromFile(final File file) throws IOException { final InputStream is = new FileInputStream(file); // Get the size of the file final long length = file.length(); // You cannot create an array using a long type. // It needs to be an int type. // Before converting to an int type, check // to ensure that file is not larger than Integer.MAX_VALUE. if (length > Integer.MAX_VALUE) { // File is too large is.close(); throw new IOException("File exceeds max value: " + Integer.MAX_VALUE); } // Create the byte array to hold the data final byte[] bytes = new byte[(int) length]; // Read in the bytes int offset = 0; int numRead = 0; while (offset < bytes.length && (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) { offset += numRead; } // Ensure all the bytes have been read in if (offset < bytes.length) { is.close(); throw new IOException("Could not completely read file" + file.getName()); } // Close the input stream and return bytes is.close(); return bytes; } public void decode(final String filePath, final Element node) throws IOException { final File imageFile = new File(filePath); final OutputStream os = new FileOutputStream(imageFile); String encodedImage = node.getTextContent(); // String decoded = decode(encodedImage); // os.write(decoded); final Runtime runtime = Runtime.getRuntime(); System.out.println("Free memory : " + runtime.freeMemory()); String[] sei = encodedImage.split("\r\n"); // System.out.println(encodedImage); System.out.println("Free memory : " + runtime.freeMemory()); for (final String element : sei) { final byte[] byteImage = Base64.decodeBase64(element); try { os.write(byteImage); } catch (final FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } } os.close(); System.out.println("Free memory : " + runtime.freeMemory()); encodedImage = null; sei = null; System.gc(); System.out.println("Free memory : " + runtime.freeMemory()); } /******************************************************************************************************************** * $Id: Base64.java,v 1.4 2002/12/24 15:17:17 russgold Exp $ * * Copyright (c) 2000-2002 by Russell Gold * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to permit * persons to whom the Software is furnished to do so, subject to the * following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN * NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE * USE OR OTHER DEALINGS IN THE SOFTWARE. * *******************************************************************************************************************/ public void encode(final String filePath, final Element node) throws IOException { // ByteArrayOutputStream baos = null; try { final File imageFile = new File(filePath); final byte[] array = getBytesFromFile(imageFile); final String encodedImage = Base64.encodeBase64String(array); node.setTextContent(encodedImage); // store it inside node } catch (final IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }