Declaration String to bytes variable in Smart Card Coding


/**

* This program is really useful for programmer who is so lazy

* to type word/ sentence in bytes when he/she codes in Smart card

*/



import java.lang.*;

/**

* @version 1.0

* @author kapulaga

*

*/

public class stringtobyte {



public stringtobyte(String variablename, String variablevalue)

{

int i;

System.out.print("byte[] "+variablename+"={");

for(i=0;i

{

if(i

System.out.print("'"+variablevalue.charAt(i)+"'"+",");

else

System.out.print("'"+variablevalue.charAt(i)+"'"+"};");

}



}





public static void main(String[] args) {

stringtobyte stb = new stringtobyte("variable","byte value");



}



}






CANNOT_PLAY_SCRIPT

If you get this error :
An internal error occurred during: "Launching baru".
Can't find resource for bundle java.util.PropertyResourceBundle, key CANNOT_PLAY_SCRIPT

Just restart your developer suit

It works for me :D

Prefix URL

We should declare prefix URL as global variable
For example :
public final static byte[] prefix = { '/', 'm', 's', 'g' };

this prefix will be called by one or more html pages
Here is example for form with post action
action="msg"
or href URL :
href="msg"

Afterwards, we should add it in SCWS container. Type it in your servlet constructor.
servletContainer.add(this, new ByteString(prefix));

Put your sensitive variable in RAM

// declare variable
byte[] requestParameterBuffer;
// allocate it in RAM , ensure the memory length
requestParameterBuffer = JCSystem.makeTransientByteArray(
(short) (queryString.length() * 2), JCSystem.CLEAR_ON_RESET);

JCSystem reset / clean memoryOptions :

• JCSystem.CLEAR_ON_DESELECT
• JCSystem.CLEAR_ON_RESET

Static .. Static Variable

Here are smart card programming rules :

• It is better to use static variable then use instance variable.
• Constants variable should be declare as static final variable
• Local variable is accessed faster than global variable

Example Declaration Variable in Smart Card Web Server :

public static final byte[] PARAMETER = { 'P', 'a', 'r', 'a', 'm', 'e', 't','e', 'r', ' ', ':', ' ' };
public final static byte[] PROTOCOL = { 'P', 'r', 'o', 't', 'o', 'c', 'o', 'l', ':' };

No String No Integer

I have just known that there is no integer and string in Smart Card program.
So what are the data type ?

• byte
• ByteString
• short
  

We should be aware with memory management :)

doGet()

I wrote my first servlet code in Smart Card Web Server.
Firstly, here is my html code :

Username:

and this following code is part of my servlet code :

public void doGet(HttpCardServletRequest req, HttpCardServletResponse resp)
throws Exception {

try {

ByteString queryString = req.getQueryString();
if (queryString != null) {

byte[] hello = { 'h', 'e', 'l', 'l','o' ,' '};


ByteString temp=queryString.substring((short)5, queryString.length());

// set header
resp.setStatus(HttpCardServletResponse.SC_OK);
resp.setContentType(stringContainer
.getConstantString(HttpStringContainer.TEXT_PLAIN_KEY));

int length = hello.length+temp.length();

resp.setContentLength(length);
// write body

HttpCardServletOutputStream out = resp.getOutputStream();
out.write(hello,(short)0,(short)hello.length);
out.write(temp);

}
} catch (Exception e) {
resp.setStatus(HttpCardServletResponse.SC_BAD_REQUEST);
}

}

This is the capture of the result :

testing by typing such username
Hey, it works now :D