Android学习笔记----Java字符串MD5加密

 1 /**
 2      * MD5单向加密，32位，用于加密密码，因为明文密码在信道中传输不安全，明文保存在本地也不安全
 3      *
 4      * @param str
 5      * @return
 6      */
 7     public static String md5(String str) {
 8         MessageDigest md5 = null;
 9         try {
10             md5 = MessageDigest.getInstance("MD5");
11         } catch (Exception e) {
12             e.printStackTrace();
13             return "";
14         }
15 
16         char[] charArray = str.toCharArray();
17         byte[] byteArray = new byte[charArray.length];
18 
19         for (int i = 0; i < charArray.length; i++) {
20             byteArray[i] = (byte) charArray[i];
21         }
22         byte[] md5Bytes = md5.digest(byteArray);
23 
24         StringBuffer hexValue = new StringBuffer();
25         for (int i = 0; i < md5Bytes.length; i++) {
26             int val = ((int) md5Bytes[i]) & 0xff;
27             if (val < 16) {
28                 hexValue.append("0");
29             }
30             hexValue.append(Integer.toHexString(val));
31         }
32         return hexValue.toString();
33     }