base64.bte

java操作excel的类

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<%bte.tpl name=pageTitle%>Base64<%/bte.tpl%>
<%bte.tpl name=description%>Encode and decode base 64 in Java.<%/bte.tpl%>
<%bte.tpl name=keywords%>base, 64, base64, base, 64, base64, base, 64, base64, encode, decode, encode, decode<%/bte.tpl%>
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<div class=i18n>
    Internationalization - included languages:
    <ul>	
    <li>English</li> 
    </ul>
    Translations gladly accepted.  Please translate
    <a href="Base64.properties.html">Base64.properties</a>.<br>
	You may want to use: 
	<a href="http://ostermiller.org/attesoro/">Attesoro - A Java Translation Editor</a>
</div>

<p>Bas64 encoding and decoding of data from Java.  Encode and decode methods for Strings, byte arrays, and streams.</p>

<p>Base64 is needed in many places other than its original use as an encoding format for transferring attachments in email.
It can be used anytime binary or arbitrary data needs to be represented in
common printable characters.  For example to connect to a web page that requires a username and password (basic authentication) you need to Base64 encode the username and password.  (See the example)<br>

<br clear=all>

<div class=examplecode><h3>Example</h3>
<pre><span class=identifier>URL url </span><span class=operator>= </span><span class=reservedWord>new </span><span class=identifier>URL</span><span class=separator>(</span><span class=literal>&quot;http://....&quot;</span><span class=separator>);
</span><span class=identifier>HttpURLConnection connection </span><span class=operator>= </span><span class=separator>(</span><span class=identifier>HttpURLConnection</span><span class=separator>)</span><span class=identifier>url</span><span class=separator>.</span><span class=identifier>openConnection</span><span class=separator>();
</span><span class=identifier>connection</span><span class=separator>.</span><span class=identifier>setRequestProperty</span><span class=separator>(
    </span><span class=literal>&quot;Authorization&quot;</span><span class=separator>, 
    </span><span class=literal>&quot;Basic &quot; </span><span class=operator>+ </span><span class=identifier>Base64</span><span class=separator>.</span><span class=identifier>encode</span><span class=separator>(
        </span><span class=identifier>username </span><span class=operator>+ </span><span class=literal>&quot;:&quot; </span><span class=operator>+ </span><span class=identifier>password
    </span><span class=separator>)
);      
</span><span class=identifier>InputStream in </span><span class=operator>= </span><span class=identifier>connection</span><span class=separator>.</span><span class=identifier>getInputStream</span><span class=separator>();</span></pre>
Use base64 to add a basic authentication to an HTTP request.
</div>

<p>Be aware that Base64 encoding in <i>not</i> encryption.  Base64 scrambles the
output and it may appear to be unreadable, but it is easily deciphered by
anybody with a little experience or time.  Base64 encoded strings will often end
in one or two equal signs, and they will have only letters, numbers, pluses, and slashes.
Once somebody figures out that it is in Base64, it is just a matter of running
the decode method on it.  Furthermore, real encryption algorithms will change
the entire output if one bit in the input changes.  If you change a letter in a
your message and then re-encode it with Base64, only a few characters will
change.  Base64 is not a substitute for encryption.  Base64 used this way is
obfuscation, and rather poor obfuscation at that.  It may be a disservice to your
users to use Base64 as obfuscation because it gives them the impression that
their data is encrypted when it really isn't.</p>

<br clear=all>
<div class=programinstructions>
<p>To run Base64 as a stand alone program use the following command line:<br>
<b>java&nbsp;-classpath&nbsp;utils.jar&nbsp;com.Ostermiller.util.Base64&nbsp;&lt;files&gt;</b></p>

<pre>Base64 [-eldagxfqQvV] &lt;files&gt;
Encode or decode using the base64 format.
  If no files are specified standard input and output will be used.
  --help            Print this help message.
  --version         Print out the version number.
  --about           Print out license and contact info.
  -g --guess        Guess from contents whether to decode or encode. (default)
  -e --encode       Apply base64 encoding.
  -l --lines        Insert line breaks when encoding. (default)
  --nolines         Insert no line breaks when encoding.
  -d --decode       Remove base64 encoding.
  -a --decodeall    When decoding, attempt badly formatted files.
  --decodegood      Don't decode badly formatted files.  (default)
  -x --ext &lt;ext&gt;    File extension to use. (default: base64)
  -f --force        Overwrite files without prompting
  --noforce         Don't overwrite files.  (default)
  -v --verbose      Print a message for each file encoded or decoded. (default)
  -q --quiet        Print error messages.
  -Q --reallyquiet  Print nothing.</pre>
</div>

<p>[<a href="./#download">Download /w Source</a> |
<a href="http://www.gjt.org/servlets/JCVSlet/log/gjt/com/Ostermiller/util/Base64.java/0">Version History</a> |
<a href="Base64.java.html">Browse Source</a> |
<a href="doc/com/Ostermiller/util/Base64.html">Documentation</a>]</p>

<h2><name="links">Links</a></h2>
<table border=2 cellpadding=5>
<tr><th>Author</th><th>License</th><th>Features</th></tr>
<tr><td>
Stephen Ostermiller<br>
<a href="http://ostermiller.org/utils/Base64.html">com.Ostermiller.util.Base64</a>
</td><td>
Open source, GPL
</td><td>
Encodes and decodes strings, byte arrays, files, and streams from static methods.
</td></tr>

<tr><td>
Robert W. Harder<br>
<a href="http://iharder.sourceforge.net/base64/">Base64</a>
</td><td>
Open source, public domain
</td><td>
Encodes and decodes strings, byte arrays, and objects from static methods.  It will
encode and decode streams if you instantiate a Base64.InputStream or a Base64.OutputStream.
</td></tr>

<tr><td>
Roedy Green<br>
<a href="http://mindprod.com/jglossbase64.html">Java Glossary</a>
<a href="http://mindprod.com/products.html#BASE64">com.mindprod.base64.base64</a>
</td><td>
Open source, freeware (except military)
</td><td>
Encodes from byte arrays to strings, decodes from strings to byte arrays.
</td></tr>

<tr><td>
Kevin Kelley<br>
<a href="http://kevinkelley.mystarband.net/java/goodies.html">Base64</a>
</td><td>
Open source, GPL
</td><td>
Encodes and decodes from byte arrays to byte arrays.
</td></tr>

<tr><td>
Bob Withers<br>
<a href="http://www.ruffboy.com/download.htm">Base64</a>
</td><td>
Open source, freeware (any purpose with attribution)
</td><td>
Encodes and decodes from byte arrays to byte arrays and comes with C++ code too.</td></tr>

<tr><td>
Tom Daley<br>
<a href="http://www.javaworld.com/javaworld/javatips/jw-javatip36-p2.html">JavaWorld Tip</a>
</td><td>
unknown
</td><td>
Annotated code and nifty graphic that shows how
Base64 encoding works. Supports byte array to byte array operations.
</td></tr>

<tr><td>
Sinotar<br>
<a href="http://www.sinotar.com/download/base64/README.html">com.sinotar.algorithm.Base64</a>
</td><td>
Open source, free only for personal use.
</td><td>
Encodes from byte arrays to strings, decodes from strings to byte arrays.
</td></tr>

</table>
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