Class Import Can't be Resolved

[Jeremy Severson]

Hey All,

I created a class that I want to use for encrypting a string with RC4 and then return the encrypted string only problem is I seem to be having trouble getting the class to import. I am not sure if my import statement is wrong or if there is an issue with my class.

So I put my compiled class file into 'WEB-INF/classes' folder and here is the class code (code is sloppy now but I will clean it up once I have my class working),

public class Rc4 {
	
	public Rc4()
	{
	};

	public String encrypt(String cipher, String key)
	{
		int outputList[] = new int[cipher.length()];
		String[] hexes = {"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"};
		String output = new String();

		String testOutput = new String();

		int i=0;
		int a=0;
		int b=0;
		int j=0;

		int sbox[] = new int[256];
		int mykey[] = new int[256];

		// Convert cipher to an array of character codes
		int mtxt[] = new int[cipher.length()];
		for (i=0; i < cipher.length(); i++) {
			mtxt[i] = (int)cipher.charAt(i);
		}

		// Convert key to an array of character codes
		int mkey[] = new int[key.length()];
		for (i=0; i < key.length(); i++) {
			mkey[i] = (int)key.charAt(i);
			
		}

		// Initialize Key
		int tempSwap;
		int intLength = mkey.length;
		for (a=0; a < 256; a++) {
			mykey[a] = mkey[(a%intLength)];
			sbox[a] = a;
		}
		for (a=0; a< 256; a++) {
			b = (b+sbox[a]+mykey[a]) % 256;
			tempSwap = sbox[a];
			sbox[a] = sbox[b];
			sbox[b] = tempSwap;
		}

		// Do RC4 Encryption
		i=0;
		j=0;
		int k;
		int temp;
		int cipherby;
		for (a=0; a<mtxt.length; a++) {
			i = (i+1) % 256;
			j = (j+sbox[i])%256;
			temp = sbox[i];
			sbox[i] = sbox[j];
			sbox[j] = temp;
			int idx = (sbox[i]+sbox[j]) % 256;
			k = sbox[idx];
			cipherby = mtxt[a]^k;
			outputList[a] = cipherby;
		}

		// Convert string to hex
		for (i=0; i<outputList.length; i++) {
			output = output + hexes[outputList[i] >> 4] + hexes[outputList[i] & 0xf];
		}
		
		return output;
		
	}; // Encrypt
	
} // class Rc4

Then in my jsp file this is what I put,

<%@ page import="Rc4" %>
<%

Rc4 r = new Rc4();
String rOutput = new String();
rOutput = r.encrypt("Test String", "99991234");

%>
(The rest of the code is just html to output the encrypted string)

But when I run the jsp this is what I get (had to use code tag because of abbreviation rule on forum),

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: Unable to compile class for JSP: 


An error occurred at line: 6 in the generated java file
The import Rc4 cannot be resolved

An error occurred at line: 4 in the jsp file: /cipher.jsp
Rc4 cannot be resolved to a type
1: <%@ page import="Rc4" %>
2: <%
3: 
4: Rc4 r = new Rc4();
5: String rOutput = new String();
6: rOutput = r.encrypt("Test String", "99991234");
7: 


An error occurred at line: 4 in the jsp file: /cipher.jsp
Rc4 cannot be resolved to a type
1: <%@ page import="Rc4" %>
2: <%
3: 
4: Rc4 r = new Rc4();
5: String rOutput = new String();
6: rOutput = r.encrypt("Test String", "99991234");
7: 


Stacktrace:
	org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:93)
	org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
	org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:451)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:319)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:298)
	org.apache.jasper.compiler.Compiler.compile(Compiler.java:286)
	org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:565)
	org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:309)
	org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:308)
	org.apache.jasper.servlet.JspServlet.service(JspServlet.java:259)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
note The full stack trace of the root cause is available in the Apache Tomcat/5.5.31 logs.

I am guessing it is something simple that I am doing wrong but can't seem to figure out what it is. Any help is appreciated.

[Paul Clapham]

Did you put your RC4 class into a package? If you didn't, then that's your problem. A class which is in a package (e.g. your JSP) can't import a class which isn't in a package.

So put it in a package. And remember that you then have to build a directory structure under WEB-INF/classes which corresponds to that package.

[Jeremy Severson]

I did not put the class in a package. So i added it to one and update the folder structure in the WEB-INF/classes directory and now it works great.

Do you always have to have your classes in a package? I thought that if I did not have a package set that I could use the class name only for the import.