Of Stack

JS implements the Base64 encoding of Chinese string utf 8 of making it the same as Java encoding

  • 2021-06-29 09:50:34
  • OfStack

An example of JS implementation for Base64 encoding of Chinese string is given in this paper.Share it for your reference, as follows:

String to encode: "select user name from user"

Encoding with JAVA, Java program: 


String sql = "select  User name  from  user ";
String encodeStr = new String(Base64.encode(sql.getBytes("UTF-8"))); //  Code 
System.out.println(encodeStr);

Get: 


c2VsZWN0IOeUqOaIt+WQjSBmcm9tIOeUqOaItw==

Decode in Java: 


sql = new String(Base64.decode(sql.getBytes()), "UTF-8");

Why use getBytes ("UTF-8") in the Java code?Because the default encoding is different in Windows and Linux environments, you must specify the encoding in order for your program to get the same encoding on different platforms

Although the codes of Html and JS are both utf-8, the Chinese code JS gets from the page is utf-16, so encoding Chinese directly with Base64 will get wrong results, so we need to go from utf-16 to utf-8 before encoding. 


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css">
<!--
body{
 margin:0px;
 padding:0px;
}
body,td{
 font-size:9pt;
}
-->
</style>
<script type="text/JavaScript">
<!--
var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
// take Ansi Encoded string Base64 Code 
function encode64(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) | (chr2 >> 4);
enc3 = ((chr2 & 15) << 2) | (chr3 >> 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;
}
// take Base64 Encoding String Conversion Ansi Encoded String 
function decode64(input) {
var output = "";
var chr1, chr2, chr3 = "";
var enc1, enc2, enc3, enc4 = "";
var i = 0;
if (input.length % 4 != 0) {
return "";
}
var base64test = /[^A-Za-z0-9\+\/\=]/g;
if (base64test.exec(input)) {
return "";
}
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 << 2) | (enc2 >> 4);
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
chr3 = ((enc3 & 3) << 6) | enc4;
output = output + String.fromCharCode(chr1);
if (enc3 != 64) {
output += String.fromCharCode(chr2);
}
if (enc4 != 64) {
output += String.fromCharCode(chr3);
}
chr1 = chr2 = chr3 = "";
enc1 = enc2 = enc3 = enc4 = "";
} while (i < input.length);
return output;
}
function utf16to8(str) {
 var out, i, len, c;
 out = "";
 len = str.length;
 for(i = 0; i < len; i++) {
  c = str.charCodeAt(i);
  if ((c >= 0x0001) && (c <= 0x007F)) {
   out += str.charAt(i);
  } else if (c > 0x07FF) {
   out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
   out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));
   out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
  } else {
   out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));
   out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));
  }
 }
 return out;
}
function utf8to16(str) {
 var out, i, len, c;
 var char2, char3;
 out = "";
 len = str.length;
 i = 0;
 while(i < len) {
  c = str.charCodeAt(i++);
  switch(c >> 4) {
   case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
    // 0xxxxxxx
    out += str.charAt(i-1);
    break;
   case 12: case 13:
    // 110x xxxx  10xx xxxx
    char2 = str.charCodeAt(i++);
    out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
    break;
   case 14:
    // 1110 xxxx 10xx xxxx 10xx xxxx
    char2 = str.charCodeAt(i++);
    char3 = str.charCodeAt(i++);
    out += String.fromCharCode(((c & 0x0F) << 12) |
    ((char2 & 0x3F) << 6) |
    ((char3 & 0x3F) << 0));
    break;
  }
 }
 return out;
}
//  Test Code   start 
var de = encode64(utf16to8("select  User name  from  user "));
document.writeln(de+"<br>");
var ee = utf8to16(decode64(de))
document.writeln(ee);
//  Test Code   End 
//-->
</script>
</head>
<body>
</body>
</html>

The above codes are all from the Internet, they get the correct results after piecing together, thank your predecessors here

PS: Here are a few more online tools for base64 encoding and decoding, which I believe will be used in future development:

BASE64 Encoding and Decoding Tool:
http://tools.ofstack.com/transcoding/base64

Online Picture Conversion BASE64 Tool:
http://tools.ofstack.com/transcoding/img2base64

More readers interested in JavaScript related content can view this site's topics: JavaScript Switching Special Effects and Techniques Summary, JavaScript Find Algorithmic Techniques Summary, JavaScript Animation Special Effects and Techniques Summary, JavaScript Errors and Debugging Techniques Summary, JavaScript Data Structure and Algorithmic Techniques Summary,Summary of JavaScript Traversal Algorithms and Techniques and Summary of JavaScript Mathematical Operation Usage

I hope that the description in this paper will be helpful to everyone's JavaScript program design.

Related articles: