Java MD5加密

---------------MD5------------------------
-------------------------------------------
/**
*
*/
package md5;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import sun.misc.BASE64Encoder;

/**
* @author Administrator
*
*/
public class Encoder {
/** */
/**
* 利用MD5进行加密
*
* @param str
*            待加密的字符串
* @return 加密后的字符串
* @throws NoSuchAlgorithmException
*             没有这种产生消息摘要的算法
* @throws UnsupportedEncodingException
*/
public String EncoderByMd5(String str) throws NoSuchAlgorithmException,
UnsupportedEncodingException {
// 确定计算方法
MessageDigest md5 = MessageDigest.getInstance("MD5");
BASE64Encoder base64en = new BASE64Encoder();
// 加密后的字符串
String newstr = base64en.encode(md5.digest(str.getBytes("utf-8")));
return newstr;
}

/** */
/**
* 判断用户密码是否正确
*
* @param newpasswd
*            用户输入的密码
* @param oldpasswd
*            数据库中存储的密码－－用户密码的摘要
* @return
* @throws NoSuchAlgorithmException
* @throws UnsupportedEncodingException
*/
public boolean checkpassword(String newpasswd, String oldpasswd)
throws NoSuchAlgorithmException, UnsupportedEncodingException {
if (EncoderByMd5(newpasswd).equals(oldpasswd)){
return true;
}else{
return false;
}
}
}
---------------Servlet------------------------
-------------------------------------------
package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.security.NoSuchAlgorithmException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import md5.Encoder;

public class LoginServlet extends HttpServlet {

/**
* Constructor of the object.
*/
public LoginServlet() {
super();
}

/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
boolean result=false;
response.setContentType("text/html;charset=UTF-8");
PrintWriter out=response.getWriter();
Encoder md5=new Encoder();
try {
result=md5.checkpassword("a", "DMF1ucDxtqgxw5niaXcmYQ==");
System.out.println(md5.EncoderByMd5("a"));
} catch (NoSuchAlgorithmException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}if(result==true){
out.println("通过MD5验证。。");
}else{
out.println("未通过MD5验证。。");
}
}

/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doGet(request,response);
}

/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}

}