js/java中文字符串Base64编解码源码

小鱼儿 2022-04-10 14:17 514阅读 0赞

## js/java中文字符串Base64编解码源码 ##

1.  js Base64编码源码

使用方法：
       var base64 = new Base64();
       base64.encode(str);
       base64.decode(str);
       注意：如果编码后的字符串要作为URL的一部分，请再使用encodeURIComponent()进行编码。

1.  java Base64编码源码

public class Base64Utils { 
    
       private static String _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
    
       private Base64Utils(){ throw new AssertionError();}
    
       /** * Base64编码 * @param input 字符串 * @return 编码 */
       public static String encode(String input) { 
           String output = "";
           char chr1, chr2, chr3, enc1, enc2, enc3, enc4;
           int i = 0;
           input = _utf8_encode(input);
           while (i < input.length()) { 
               chr1 = input.charAt(i++);
               chr2 = input.charAt(i++);
               chr3 = input.charAt(i++);
               enc1 = (char) (chr1 >> 2);
               enc2 = (char) (((chr1 & 3) << 4) | (chr2 >> 4));
               enc3 = (char) (((chr2 & 15) << 2) | (chr3 >> 6));
               enc4 = (char) (chr3 & 63);
               if (Double.isNaN(chr2)) { 
                   enc3 = enc4 = 64;
               } else if (Double.isNaN(chr3)) { 
                   enc4 = 64;
               }
               output = output + _keyStr.charAt(enc1) + _keyStr.charAt(enc2) + _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
           }
           return output;
       }
    
       /** * Base64 解码 * @param input 字符串 * @return 解码字符串 */
       public static String decode(String input) { 
           String output = "";
           char chr1, chr2, chr3, enc1, enc2, enc3, enc4;
           int i = 0;
           input = input.replace("[^A-Za-z0-9\\+\\/\\=]", "");
           while (i < input.length()) { 
               enc1 = (char) _keyStr.indexOf(input.charAt(i++));
               enc2 = (char) _keyStr.indexOf(input.charAt(i++));
               enc3 = (char) _keyStr.indexOf(input.charAt(i++));
               enc4 = (char) _keyStr.indexOf(input.charAt(i++));
               chr1 = (char) ((enc1 << 2) | (enc2 >> 4));
               chr2 = (char) (((enc2 & 15) << 4) | (enc3 >> 2));
               chr3 = (char) (((enc3 & 3) << 6) | enc4);
               output = output + chr1;
               if (enc3 != 64) { 
                   output = output + chr2;
               }
               if (enc4 != 64) { 
                   output = output + chr3;
               }
           }
           output = _utf8_decode(output);
           return output;
       }
    
       /** * UTF-8编码 * @param string 字符串 * @return 编码 */
       private static String _utf8_encode(String string) { 
           string = string.replace("\r\n", "\n");
           String utftext = "";
           for (int n = 0; n < string.length(); n++) { 
               char c = string.charAt(n);
               if (c < 128) { 
                   utftext += c;
               } else if ((c > 127) && (c < 2048)) { 
                   utftext += (char) ((c >> 6) | 192);
                   utftext += (char) ((c & 63) | 128);
               } else { 
                   utftext += (char) ((c >> 12) | 224);
                   utftext += (char) (((c >> 6) & 63) | 128);
                   utftext += (char) ((c & 63) | 128);
               }
    
           }
           return utftext;
       }
    
       /** * UTF-8 解码 * @param utftext 字符串 * @return 解码 */
       private static String _utf8_decode(String utftext) { 
           String string = "";
           int i = 0;
           int c, c1, c2;
           while (i < utftext.length()) { 
               c = utftext.charAt(i);
               if (c < 128) { 
                   string += (char) c;
                   i++;
               } else if ((c > 191) && (c < 224)) { 
                   c2 = utftext.charAt(i + 1);
                   string += (char) (((c & 31) << 6) | (c2 & 63));
                   i += 2;
               } else { 
                   c2 = utftext.charAt(i + 1);
                   c1 = utftext.charAt(i + 2);
                   string += (char) (((c & 15) << 12) | ((c2 & 63) << 6) | (c1 & 63));
                   i += 3;
               }
           }
           return string;
       }
    }