My whim today, is to create an EJB that generates the SHA-1 message digest from the contents of a simple form.
I will be using GlassFish 3.1.2 to deploy my application. The SHA-1 is generated by using the MessageDigest class, found in the java.security package.
So, the first step is to create a Dynamic Web Project in Eclipse. It generates a default JSP. I use this page to hold the HTML contents of the form.
I will be using GlassFish 3.1.2 to deploy my application. The SHA-1 is generated by using the MessageDigest class, found in the java.security package.
So, the first step is to create a Dynamic Web Project in Eclipse. It generates a default JSP. I use this page to hold the HTML contents of the form.
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=UTF-8">
<title>Test Form</title>
</head>
<body>
<form method="POST" action="HashIt">
Username: <input name="username"/> <br/>
Password: <input name="password" type="password"><br/>
<input type="submit" value="Submit">
</form>
</body>
</html>
Then I create the servlet that processes this form. It does the following,- Receive the contents of the form (doPost)
- Use the EJB to actually generate the SHA-1 and render the result
package com.whycouch;
import java.io.IOException;
import javax.ejb.EJB;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* This class processes the requests from the form
* @author Hathy
*/
@WebServlet("/HashIt")
public class HashIt extends HttpServlet {
private static final long serialVersionUID = 1L;
@EJB
private Hash hash;
public HashIt() {
super();
}
protected void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
// Let us always use the doPost
doPost(request,response);
}
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String username=request.getParameter("username");
String password=request.getParameter("password");
if(username==null || username.length()==0)
username="EMPTY";
if(password==null || password.length()==0)
password="EMPTY";
response.getWriter().println(
"The SHA-1 of the form data is "+
hash.digest(username+password)
);
}
}
Finally, I create the EJB itself, which is nothing but a stateless session bean.
package com.whycouch;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import javax.ejb.LocalBean;
import javax.ejb.Stateless;
import com.sun.xml.wss.impl.misc.Base64;
/**
* This is the EJB that actually generates the SHA-1
* for the input it is provided with
*
* @author Hathy
*/
@Stateless
@LocalBean
public class Hash {
MessageDigest sha1;
// Initialize the MessageDigest to use SHA-1
// as its algorithm
public Hash() {
try {
sha1=MessageDigest.getInstance("SHA-1");
} catch (NoSuchAlgorithmException e) {
System.err.println("Unable to find SHA-1");
}
System.out.println("Initialized");
}
// Generate the message digest, and then convert it
// into a Base64 string
public String digest(String data){
if(data==null)
return "";
byte[] output = sha1.digest(data.getBytes());
return Base64.encode(output);
}
}
The Base64 utility class that I have used was found in the webservices-rt.jar, that comes along with the GlassFish server. So, when you run the application, and submit the form, you should see a message like,
The SHA-1 of the form data is yPf+Ow5BvoRtVodZLPIBj/biJoc=
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