MD5加密

package common;

/**
* MD5加密
* @author heweina
* common.Password_encrypt.java
* 2011-3-2 下午07:30:49
*/
public class Password_encrypt {
public Password_encrypt() {
}
//对外提供的方法
public String pw_encrypt(String password) {
if (password == null || password.equals("") || password.length() == 32) {
return password;
}
String s = new String();
try {
java.security.MessageDigest alga = java.security.MessageDigest
.getInstance("MD5");
alga.update(password.getBytes());
byte[] digesta = alga.digest();
Password_encrypt sss = new Password_encrypt();
s = sss.byte2hex(digesta);
alga.reset();
} catch (Exception e) {
System.err.println("md5加密方法错误!");
}
return s;
}

//md5加密的根本方法
public String byte2hex(byte[] b)
{
String hs = "";
String stmp = "";
for (int n = 0; n < b.length; n++) {
stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
if (stmp.length() == 1)
hs = hs + "0" + stmp;
else
hs = hs + stmp;
}
return hs.toUpperCase();
}

public static void main(String[] args) {

// String password = "admin";
// java.security.MessageDigest alga;
// try {
// alga = java.security.MessageDigest.getInstance("MD5");
// alga.update(password.getBytes());
// byte[] digesta = alga.digest();
// Password_encrypt sss = new Password_encrypt();
// String newPassword = sss.byte2hex(digesta);
// System.out.println(newPassword);
//
// } catch (Exception e) {
// e.printStackTrace();
// }
System.out.println(new Password_encrypt().pw_encrypt("123456789111111122"));
}
}