java中用MessageDigest类，可以用来加密MD5。

首先创建一个MessageDigest对象

MessageDigest digest = MessageDigest.getInstance("MD5");

 

调用digest.digest(psd.getBytes());会返回一个16位的字符串，然后使用规定的模板转换为32位即可。

for (byte b : bs) {                String hexString = Integer.toHexString(b & 0xff);                if (hexString.length() < 2) {                    hexString = "0" + hexString;                }                stringBuffer.append(hexString);            }

 

 

完整的代码：

1 import java.security.MessageDigest; 2 import java.security.NoSuchAlgorithmException; 3  4 public class Md5Util { 5  6     /** 7      * @param args 8      */ 9     public static void main(String[] args) {10         String psd = "123";11         encoder(psd);12     }13 14     private static void encoder(String psd) {15         try {16             MessageDigest digest = MessageDigest.getInstance("MD5");17             byte[] bs = digest.digest(psd.getBytes());18             System.out.println(bs.length);19             StringBuffer stringBuffer = new StringBuffer();20             for (byte b : bs) {21                 String hexString = Integer.toHexString(b & 0xff);22                 if (hexString.length() < 2) {23                     hexString = "0" + hexString;24                 }25                 stringBuffer.append(hexString);26             }27             System.out.println(stringBuffer.toString());28         } catch (NoSuchAlgorithmException e) {29             e.printStackTrace();30         }31 32     }33 34 }