Base64编码的java实现

 1 /** Base64编码数组 */
 2         private static final String base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
 3 
 4     /**
 5      * Base64 编码
 6      * @param str 待编码字符串
 7      * @return
 8      */
 9     public static String base64encode(String str) {
10         String out = "";
11         int i = 0;
12         int len = str.length();
13         int c1, c2, c3;
14         while (i < len) {
15             c1 = str.charAt(i++) & 0xff;
16             if (i == len) {
17                 out += base64EncodeChars.charAt(c1 >> 2);
18                 out += base64EncodeChars.charAt((c1 & 0x3) << 4);
19                 out += "==";
20                 break;
21             }
22             c2 = str.charAt(i++);
23             if (i == len) {
24                 out += base64EncodeChars.charAt(c1 >> 2);
25                 out += base64EncodeChars.charAt(((c1 & 0x3) << 4)
26                         | ((c2 & 0xF0) >> 4));
27                 out += base64EncodeChars.charAt((c2 & 0xF) << 2);
28                 out += "=";
29                 break;
30             }
31             c3 = str.charAt(i++);
32             out += base64EncodeChars.charAt(c1 >> 2);
33             out += base64EncodeChars.charAt(((c1 & 0x3) << 4)
34                     | ((c2 & 0xF0) >> 4));
35             out += base64EncodeChars.charAt(((c2 & 0xF) << 2)
36                     | ((c3 & 0xC0) >> 6));
37             out += base64EncodeChars.charAt(c3 & 0x3F);
38         }
39         return out;
40     }    

1     /**
2      * 将Base64编码转换为URL安全的Base64编码
3      * @param str Base64编码的字符串
4      * @return
5      */
6     private static String safe64(String str) {
7         String result = str.replace("+", "-");
8         return result.replace("/", "_");
9     }