2019独角兽企业重金招聘Python工程师标准>>> 
BASE64 编码是一种常用的字符编码，在很多地方都会用到。JDK 中提供了非常方便的 BASE64Encoder 和 BASE64Decoder，用它们可以非常方便的完成基于 BASE64 的编码和解码。下面是本人编的两个小的函数，分别用于 BASE64 的编码和解码：
// 将 s 进行 BASE64 编码
public static String getBASE64(String s) {
if (s == null) return null;
return (new sun.misc.BASE64Encoder()).encode( s.getBytes() );
}
// 将 BASE64 编码的字符串 s 进行解码
public static String getFromBASE64(String s) {
if (s == null) return null;
BASE64Decoder decoder = new BASE64Decoder();
try {
byte[] b = decoder.decodeBuffer(s);
return new String(b);
} catch (Exception e) {
return null;
}
}
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解决了对中文的不支持问题.
先用escape()对中文进行编码.然后再进行base64编码.
解码时,再加入unescape()对中文进行解码.
<html>
<head>
<title>base64 Encoding/Decoding</title>
</head>
<script type="text/javascript"><!--
var keyStr = "ABCDEFGHIJKLMNOP"
"QRSTUVWXYZabcdef"
"ghijklmnopqrstuv"
"wxyz0123456789 /"
"=";
function encode64(input) {
input = escape(input);
var output = "";
var chr1, chr2, chr3 = "";
var enc1, enc2, enc3, enc4 = "";
var i = 0;
do {
chr1 = input.charCodeAt(i );
chr2 = input.charCodeAt(i );
chr3 = input.charCodeAt(i );
enc1 = chr1 >> 2;
enc2 = ((chr1 & 3) 4);
enc3 = ((chr2 & 15) 6);
enc4 = chr3 & 63;
if (isNaN(chr2)) {
enc3 = enc4 = 64;
} else if (isNaN(chr3)) {
enc4 = 64;
}
output = output
keyStr.charAt(enc1)
keyStr.charAt(enc2)
keyStr.charAt(enc3)
keyStr.charAt(enc4);
chr1 = chr2 = chr3 = "";
enc1 = enc2 = enc3 = enc4 = "";
} while (i < input.length);
return output;
}
function decode64(input) {
var output = "";
var chr1, chr2, chr3 = "";
var enc1, enc2, enc3, enc4 = "";
var i = 0;
// remove all characters that are not A-Z, a-z, 0-9, , /, or =
var base64test = /[^A-Za-z0-9\ \/\=]/g;
if (base64test.exec(input)) {
alert("There were invalid base64 characters in the input text.\n"
"Valid base64 characters are A-Z, a-z, 0-9, ´ ´, ´/´, and ´=´\n"
"Expect errors in decoding.");
}
input = input.replace(/[^A-Za-z0-9\ \/\=]/g, "");
do {
enc1 = keyStr.indexOf(input.charAt(i ));
enc2 = keyStr.indexOf(input.charAt(i ));
enc3 = keyStr.indexOf(input.charAt(i ));
enc4 = keyStr.indexOf(input.charAt(i ));
chr1 = (enc1 4);
chr2 = ((enc2 & 15) 2);
chr3 = ((enc3 & 3) << 6) | enc4;
output = output String.fromCharCode(chr1);
if (enc3 != 64) {
output = output String.fromCharCode(chr2);
}
if (enc4 != 64) {
output = output String.fromCharCode(chr3);
}
chr1 = chr2 = chr3 = "";
enc1 = enc2 = enc3 = enc4 = "";
} while (i < input.length);
return unescape(output);
}
//--></script>
<body>
<form name="base64Form">
Type in the message you want to encode in base64, or paste<br>
base64 encoded text into the text field, select Encode or Decode, <br>
and click the button!<br>
<textarea name="theText" cols="40" rows="6"></textarea><br>
<input type="button" name="encode" value="Encode to base64"
onClick="document.base64Form.theText.value=encode64(document.base64Form.theText.value);">
<input type="button" name="decode" value="Decode from base64"
onClick="document.base64Form.theText.value=decode64(document.base64Form.theText.value);">
</form>
</body>
</html>
原文链接： http://www.dlog.cn/nicholascoder/diary/9660
