把代码扣出来自己写一个吧// Copyright (C) 1999-2002 by Jason Hunter <jhunter_AT_acm_DOT_org>. // All rights reserved. Use of this class is limited. // Please see the LICENSE for more information.package org.apache.commons.mvc.util;import java.io.*;/*** * A class to encode Base64 streams and strings. * See RFC 1521 section 5.2 for details of the Base64 algorithm. * <p> * This class can be used for encoding strings: * <blockquote><pre> * String unencoded = "webmaster:try2gueSS"; * String encoded = Base64Encoder.encode(unencoded); * </pre></blockquote> * or for encoding streams: * <blockquote><pre> * OutputStream out = new Base64Encoder(System.out); * </pre></blockquote> * * @author <b>Jason Hunter</b>, Copyright © 2000 * @version 1.2, 2002/11/01, added encode(byte[]) method to better handle * binary data (thanks to Sean Graham) * @version 1.1, 2000/11/17, fixed bug with sign bit for char values * @version 1.0, 2000/06/11 */ public class Base64Encoder extends FilterOutputStream { private static final char[] chars = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' }; private int charCount; private int carryOver; /*** * Constructs a new Base64 encoder that writes output to the given * OutputStream. * * @param out the output stream */ public Base64Encoder(OutputStream out) { super(out); } /*** * Writes the given byte to the output stream in an encoded form. * * @exception IOException if an I/O error occurs */ public void write(int b) throws IOException { // Take 24-bits from three octets, translate into four encoded chars // Break lines at 76 chars // If necessary, pad with 0 bits on the right at the end // Use = signs as padding at the end to ensure encodedLength % 4 == 0 // Remove the sign bit, // thanks to Christian Schweingruber <[email protected]> if (b < 0) { b += 256; } // First byte use first six bits, save last two bits if (charCount % 3 == 0) { int lookup = b >> 2; carryOver = b & 3; // last two bits out.write(chars[lookup]); } // Second byte use previous two bits and first four new bits, // save last four bits else if (charCount % 3 == 1) { int lookup = ((carryOver << 4) + (b >> 4)) & 63; carryOver = b & 15; // last four bits out.write(chars[lookup]); } // Third byte use previous four bits and first two new bits, // then use last six new bits else if (charCount % 3 == 2) { int lookup = ((carryOver << 2) + (b >> 6)) & 63; out.write(chars[lookup]); lookup = b & 63; // last six bits out.write(chars[lookup]); carryOver = 0; } charCount++; // Add newline every 76 output chars (that's 57 input chars) if (charCount % 57 == 0) { out.write('\n'); } } /*** * Writes the given byte array to the output stream in an * encoded form. * * @param buf the data to be written * @param off the start offset of the data * @param len the length of the data * @exception IOException if an I/O error occurs */ public void write(byte[] buf, int off, int len) throws IOException { // This could of course be optimized for (int i = 0; i < len; i++) { write(buf[off + i]); } } /*** * Closes the stream, this MUST be called to ensure proper padding is * written to the end of the output stream. * * @exception IOException if an I/O error occurs */ public void close() throws IOException { // Handle leftover bytes if (charCount % 3 == 1) { // one leftover int lookup = (carryOver << 4) & 63; out.write(chars[lookup]); out.write('='); out.write('='); } else if (charCount % 3 == 2) { // two leftovers int lookup = (carryOver << 2) & 63; out.write(chars[lookup]); out.write('='); } super.close(); } /*** * Returns the encoded form of the given unencoded string. The encoder * uses the ISO-8859-1 (Latin-1) encoding to convert the string to bytes. * For greater control over the encoding, encode the string to bytes * yourself and use encode(byte[]). * * @param unencoded the string to encode * @return the encoded form of the unencoded string */ public static String encode(String unencoded) { byte[] bytes = null; try { bytes = unencoded.getBytes("8859_1"); } catch (UnsupportedEncodingException ignored) { } return encode(bytes); } /*** * Returns the encoded form of the given unencoded string. * * @param bytes the bytes to encode * @return the encoded form of the unencoded string */ public static String encode(byte[] bytes) { ByteArrayOutputStream out = new ByteArrayOutputStream((int) (bytes.length * 1.37)); Base64Encoder encodedOut = new Base64Encoder(out);
try { encodedOut.write(bytes); encodedOut.close(); return out.toString("8859_1"); } catch (IOException ignored) { return null; } } public static void main(String[] args) throws Exception { if (args.length != 1) { System.err.println( "Usage: java com.oreilly.servlet.Base64Encoder fileToEncode"); return; } Base64Encoder encoder = null; BufferedInputStream in = null; try { encoder = new Base64Encoder(System.out); in = new BufferedInputStream(new FileInputStream(args[0])); byte[] buf = new byte[4 * 1024]; // 4K buffer int bytesRead; while ((bytesRead = in.read(buf)) != -1) { encoder.write(buf, 0, bytesRead); } } finally { if (in != null) in.close(); if (encoder != null) encoder.close(); } } }
// All rights reserved. Use of this class is limited.
// Please see the LICENSE for more information.package org.apache.commons.mvc.util;import java.io.*;/***
* A class to encode Base64 streams and strings.
* See RFC 1521 section 5.2 for details of the Base64 algorithm.
* <p>
* This class can be used for encoding strings:
* <blockquote><pre>
* String unencoded = "webmaster:try2gueSS";
* String encoded = Base64Encoder.encode(unencoded);
* </pre></blockquote>
* or for encoding streams:
* <blockquote><pre>
* OutputStream out = new Base64Encoder(System.out);
* </pre></blockquote>
*
* @author <b>Jason Hunter</b>, Copyright © 2000
* @version 1.2, 2002/11/01, added encode(byte[]) method to better handle
* binary data (thanks to Sean Graham)
* @version 1.1, 2000/11/17, fixed bug with sign bit for char values
* @version 1.0, 2000/06/11
*/
public class Base64Encoder extends FilterOutputStream { private static final char[] chars = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', '+', '/'
}; private int charCount;
private int carryOver; /***
* Constructs a new Base64 encoder that writes output to the given
* OutputStream.
*
* @param out the output stream
*/
public Base64Encoder(OutputStream out) {
super(out);
} /***
* Writes the given byte to the output stream in an encoded form.
*
* @exception IOException if an I/O error occurs
*/
public void write(int b) throws IOException {
// Take 24-bits from three octets, translate into four encoded chars
// Break lines at 76 chars
// If necessary, pad with 0 bits on the right at the end
// Use = signs as padding at the end to ensure encodedLength % 4 == 0 // Remove the sign bit,
// thanks to Christian Schweingruber <[email protected]>
if (b < 0) {
b += 256;
} // First byte use first six bits, save last two bits
if (charCount % 3 == 0) {
int lookup = b >> 2;
carryOver = b & 3; // last two bits
out.write(chars[lookup]);
}
// Second byte use previous two bits and first four new bits,
// save last four bits
else if (charCount % 3 == 1) {
int lookup = ((carryOver << 4) + (b >> 4)) & 63;
carryOver = b & 15; // last four bits
out.write(chars[lookup]);
}
// Third byte use previous four bits and first two new bits,
// then use last six new bits
else if (charCount % 3 == 2) {
int lookup = ((carryOver << 2) + (b >> 6)) & 63;
out.write(chars[lookup]);
lookup = b & 63; // last six bits
out.write(chars[lookup]);
carryOver = 0;
}
charCount++; // Add newline every 76 output chars (that's 57 input chars)
if (charCount % 57 == 0) {
out.write('\n');
}
} /***
* Writes the given byte array to the output stream in an
* encoded form.
*
* @param buf the data to be written
* @param off the start offset of the data
* @param len the length of the data
* @exception IOException if an I/O error occurs
*/
public void write(byte[] buf, int off, int len) throws IOException {
// This could of course be optimized
for (int i = 0; i < len; i++) {
write(buf[off + i]);
}
} /***
* Closes the stream, this MUST be called to ensure proper padding is
* written to the end of the output stream.
*
* @exception IOException if an I/O error occurs
*/
public void close() throws IOException {
// Handle leftover bytes
if (charCount % 3 == 1) { // one leftover
int lookup = (carryOver << 4) & 63;
out.write(chars[lookup]);
out.write('=');
out.write('=');
}
else if (charCount % 3 == 2) { // two leftovers
int lookup = (carryOver << 2) & 63;
out.write(chars[lookup]);
out.write('=');
}
super.close();
} /***
* Returns the encoded form of the given unencoded string. The encoder
* uses the ISO-8859-1 (Latin-1) encoding to convert the string to bytes.
* For greater control over the encoding, encode the string to bytes
* yourself and use encode(byte[]).
*
* @param unencoded the string to encode
* @return the encoded form of the unencoded string
*/
public static String encode(String unencoded) {
byte[] bytes = null;
try {
bytes = unencoded.getBytes("8859_1");
}
catch (UnsupportedEncodingException ignored) { }
return encode(bytes);
} /***
* Returns the encoded form of the given unencoded string.
*
* @param bytes the bytes to encode
* @return the encoded form of the unencoded string
*/
public static String encode(byte[] bytes) {
ByteArrayOutputStream out =
new ByteArrayOutputStream((int) (bytes.length * 1.37));
Base64Encoder encodedOut = new Base64Encoder(out);
try {
encodedOut.write(bytes);
encodedOut.close(); return out.toString("8859_1");
}
catch (IOException ignored) { return null; }
} public static void main(String[] args) throws Exception {
if (args.length != 1) {
System.err.println(
"Usage: java com.oreilly.servlet.Base64Encoder fileToEncode");
return;
} Base64Encoder encoder = null;
BufferedInputStream in = null;
try {
encoder = new Base64Encoder(System.out);
in = new BufferedInputStream(new FileInputStream(args[0])); byte[] buf = new byte[4 * 1024]; // 4K buffer
int bytesRead;
while ((bytesRead = in.read(buf)) != -1) {
encoder.write(buf, 0, bytesRead);
}
}
finally {
if (in != null) in.close();
if (encoder != null) encoder.close();
}
}
}