JSP REFUSES to notice my CLASSES 2

scripter73 · Mar 21, 2004

Hi,

My problem is I can’t get my JSP to recognize my homemade classes. Sorry in advance for the length of this post, but need to show all info.

I’m a relative newbie to Java servlets, but here’s my 2 main class codes:

Code for User class

public class User{
private String firstName;
private String lastName;
private String emailAddress;

//constructors
public User(){}

public User(String first, String last, String email){
firstName = first;
lastName = last;
emailAddress = email;
}

//methods
public void setFirstName(String f){
firstName = f;
}

public String getFirstName(){
return firstName;
}

public void setLastName(String l){
lastName = l;
}

public String getLastName(){
return lastName;
}

public void setEmailAddress(String e){
emailAddress = e;
}

public String getEmailAddress(){
return emailAddress;
}

Code for UserIO class

import java.io.*;

public class UserIO{
public synchronized static void addRecord(User user, String filename)
throws IOException{
PrintWriter out = new PrintWriter(new FileWriter(filename,true));

out.println(user.getEmailAddress() + "|" + user.getFirstName() + "|"
+ user.getLastName());

out.close();

}
}

****************************
My Environment Setup
****************************

- Running Tomcat 4.1 with this embedded directory structure:
o \Tomcat 4.1
\webapps
\JSP
\WEB-INF
\classes User.java and UserIO.java saved here

- Running Java 2 SDK 1.4.2_02
- Environment’s System Variables:
o PATH includes c:\j2sdk1.4.2_02\bin and C:\Tomcat 4.1
o CATALINA_HOME = C:\Tomcat 4.1
o CLASSPATH = %CATALINA_HOME%\common\lib\servlet.jar;%CATALINA_HOME%\webapps\JSP\WEB-INF\classes Also tried only one of these respective directories

****************************
Error While Compiling
****************************

C:\Tomcat 4.1\webapps\JSP\WEB-INF\classes> javac User.java

C:\Tomcat 4.1\webapps\JSP\WEB-INF\classes> javac UserIO.java

Both of these compile with no problem. Now I have User.class and UserIO.class.

****************************
Run the URL.
****************************

I run

http://localhost:8080/JSP/email.html

which collects a first/lastname and email and then calls this .JSP:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Chapter 4 - Email List Application (JSP + classes)</title>
</head>

<body>

<jsp:useBean id="user" scope="session" class="User" /> ?????? How do I import

<%
String firstname = request.getParameter("firstname");
String lastname = request.getParameter("lastname");
String emailaddress = request.getParameter("emailaddress");

User user = new User(firstName,lastName,emailAddress);
UserIO.addRecord(user,"../webapps/JSP/UserEmail.txt");

%>

<h1> Thanks for joining our email list </h1>
<p> Here is the information that you entered:</p>

<table cellspacing=5 border=0>
<tr>
<td align="right">First Name:</td>
<td><%= user.getFirstName() %></td>
</tr>

<tr>
<td align="right">Last Name:</td>
<td><%= user.getLastName() %></td>
</tr>

<tr>
<td align="right">Email Address:</td>
<td><%= user.getEmailAddress() %></td>
</tr>
</table>

<p>To enter another email address, click on the Back <br> button in your browser
or the Return button shown <br> below. </p>

<form action="join_email_list.html" method="post">
<input type="submit" value="Return">
</form>

</body>
</html>

--------

Here’s the main error message I get

Cannot resolve symbol
Symbol: class User

Then it points to my code:
User user = new User(…..)

Another error is:

Cannot resolve symbol
Symbol: variable UserIO

Then it points to my code:
UserIO.addRecord….

Among other error messages I get.

How do I import my class? I've tried the <jsp:usebean> and also tried <% page import="User,UserIO" %> to no avail. Everyone says to have your compiled classes in a \classes folder and I do.

Thanks for all of your help.

Scripter73

Change Your Thinking, Change Your Life.

byam · Mar 21, 2004

put the following line at the top of your JSP page.

<%@ page import="User,UserIO" %>

scripter73 · Mar 21, 2004

Thanks, byam for responding so quickly.

I tried your suggestion. Here's what I have in my show_email_entry.jsp page:

<%@ page import="User,UserIO" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Chapter 4 - Email List Application (JSP + classes)</title>
</head>

<body>

<%
String firstname = request.getParameter("firstname");
String lastname = request.getParameter("lastname");
String emailaddress = request.getParameter("emailaddress");

User user = new User(firstName,lastName,emailAddress);
UserIO.addRecord(user,"../webapps/hJSP/UserEmail.txt");

%>

I had also previously put this within the <body> tag.

Here's the error message I get.

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

An error occurred at line: -1 in the jsp file: null

Generated servlet error:
[javac] Compiling 1 source file

C:\Tomcat 4.1\work\Standalone\localhost\hJSP\show_email_entry_jsp.java:7: '.' expected
import User;
^
C:\Tomcat 4.1\work\Standalone\localhost\hJSP\show_email_entry_jsp.java:8: '.' expected
import UserIO;
^
2 errors

Thanks for any help you can provide.

scripter73

Change Your Thinking, Change Your Life.

byam · Mar 21, 2004

My guess is you are using Java 1.4. Since Java 1.4, you can no longer import a class not under a package.

http://www.ezpublishing.com/docs/index.php/article/articleview/60/1/19/

you need to create a directory to hold the User and UserIO classes. Let say you create a directory call myPackage. i.e. the two java file will be in

%CATALINA_HOME%\webapps\JSP\WEB-INF\classes\myPackage\User.java
%CATALINA_HOME%\webapps\JSP\WEB-INF\classes\myPackage\UserIO.java

for each of the java class in the myPackage, add the following line at the begining of the class file

Code:

package myPackage

you can then compile it by
javac %CATALINA_HOME%\webapps\JSP\WEB-INF\classes\myPackage\*.java

And in your JSP, the import would be

Code:

<%@ page import="myPackage.User, myPackage.UserIO" %>

scripter73 · Mar 21, 2004

Hi byam,

This worked!!!!! I had never created a package before. I thought there was some other type of process. I didn't know all you had to do was create a directory.

I also like the idea of compiling all of the .java code at once? Is that necessary for a package?

Thanks again for breaking down the process into very understandable terms.

Take care,
scripter73

Change Your Thinking, Change Your Life.

scripter73 · Mar 21, 2004

Hey, byam,

One more question. As I become more familiar with this process (I'm coming from an ASP background), let me ask you this.

What would the classes User and UserIO be considered as? Java Beans? Servlets?

I like the idea of taking another task and writing a class for it, I'm just not sure what I should say I'm creating.

Thanks,
scripter73

Change Your Thinking, Change Your Life.

byam · Mar 22, 2004

User and UserIO are not servlet. JSP describe how to constructs a servlet. JSP container compiles JSP into a servlet. You can find the generated servlet (.java) for your JSP in %CATALINA_HOME%\work\Standalone\localhost\JSP\...

The User class can be considered as a Java bean. It has the setter and getter methods for it properties. UserIO class is not a Java bean. UserIO is just a component providing a interface to add user record. It has no getter not setter method, and has no properties.

scripter73 · Mar 22, 2004

Thanks for clearing that up a bit.

Change Your Thinking, Change Your Life.

LFI · Aug 11, 2005

byam and this site's search engine come through again!

Thanks!

--Dave

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JSP REFUSES to notice my CLASSES 2

scripter73

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byam

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