Package problems

[B Crosthwaite]

Hi Guys,

I am following a tutorial from the Head First servlets & JSPs book (not very well it would appear ).

I am trying to compile this code:

package com.example.web;
 
import com.example.model.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
 
public class BeerSelect extends HttpServlet {
 
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException {

String c = request.getParameter("color");
BeerExpert be = new BeerExpert();
List result = be.getBrands(c);

response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("Beer Selection Advice<BR>");

Iterator it = result.iterator();
while(it.hasNext()) {
out.print("<BR>try: " + it.next());
}
 
}
}

When i do the compile i get these errors:

src/com/example/web/BeerSelect.java:3: package com.example.model does not exist
import com.example.model.*;
^
src/com/example/web/BeerSelect.java:16: cannot find symbol
symbol  : class BeerExpert
location: class com.example.web.BeerSelect
BeerExpert be = new BeerExpert();
                ^
src/com/example/web/BeerSelect.java:16: cannot find symbol
symbol  : class BeerExpert
location: class com.example.web.BeerSelect
BeerExpert be = new BeerExpert();
                                    ^
3 errors

This is really frustrating as i am following everything word for word in the book.

Does anyone see where i am going wrong?
If i have not given enough info please tell me what you need to help me sort this problem out

Your help would be greatly appreciated.
Thanks,
-Ben

[B Crosthwaite]

My package directory is:

com
|
example
|
model

aaaahhhh !

Why is this not working? Pleaase Help me

Thanks,
-Ben

[Rob Spoor]

In what folder are you when you try to compile the class?

[Reinhard Horn]

Hi Ben,

if you try to compile your classes in the console window move into the src directory.

Type

javac com/example/web/BeerSelect.java

into the console and press enter.


That should work.

Kind regards

[B Crosthwaite]

Hi thanks for your reply.

My Directory is set up like this (sorry if its a bit confusing this was the best way i could lay it out)

MyProject
|
beerV1
|
classes------|-----src
|-------------------|
com----------------com
|-------------------|
example-----------example
/-----\-------------/----\
web-model-------web-model

The way I am compiling is this:

cd ~/MyProject/beerV1
javac -d classes src/com/example/web/BeerSelect.java

So i have my .java files in the src part of the directory and when i compile them the .class file gets sent to the classes part of the directory

-Ben
[ November 15, 2008: Message edited by: B Crosthwaite ]

[B Crosthwaite]

Hey Reinhard,

Thanks for your reply, however i was presented with the same errors when i tried what you said.

Any other ideas?

-Ben

[Reinhard Horn]

Do yo have a file named

BeerExpert.java

in the directory scr/com/example/model?

[B Crosthwaite]

Yes.

scr/com/example/model/BeerExpert.java

package com.example.model;
import java.util.*;
 
public class BeerExpert {
public List<String> getBrands(String color) {
List<String> brands = new ArrayList<String>();
if (color.equals("amber")) {
brands.add("Jack Amber");
brands.add("Red Moose");
}
else {
brands.add("Jail Pale Ale");
brands.add("Gout Stout");
}
return(brands);
}
}

-Ben

[Reinhard Horn]

Check your directory and file names. Correct spelling, capitalized letters etc..
I get the same errors when I remove BeerExpert.java.

[B Crosthwaite]

I have checked and double checked

This is very disheartening

Have you managed to compile my code?

-Ben

[Reinhard Horn]

Yes but I replaced the Servlet class with a normal class. How did you set the classpath of the servlet.jar file and what OS do you use?

[B Crosthwaite]

my classpath is set like this:
CLASSPATH /Library/Tomcat/Home/lib/servlet-api.jar

I am on Mac OS X (version 15.5.5)

Im sorry please can you explain what you mean by "replaced the Servlet class with a normal class" i don't fully understand.

again, thanks for you time. I really appreciate it

-Ben

[Reinhard Horn]

The errors you get are normal environment errors, meaning there is something wrong with
your directory structure or your file names. It is not a special Servlet problem. The problem would occur also with a "normal" (non Servlet) class. I did not use a servlet class to simplify things. If you want to compile a servlet you must have the servlet jar files in your classpath settings otherwise the complier would not recognize the HttpServlet class.

[Campbell Ritchie]

It is worth trying compiling the classes one at a time, leaving the class with the main method until last. When you import a class from another package the compiler seems to think that class is already compiled and ready to go.

Or (if there aren't too many classes) compile a list of classes all together

javac mypackage/Class1.java myotherpackage/Class2.java

Or even
javac mypackage/*.java

[Reinhard Horn]

You are right. (See compile Xlint Errors). The class file must be in the wrong directory or not existing.

[Reinhard Horn]

Ben,

it is the best to simply your steps.

1) make sure that BeerExpert.java is in src/com/example/model
2) make sure that BeerExpert.class is src/com/example/model
3) move to the src directory
4) compile with javac -classpath /Library/Tomcat/Home/lib/servlet-api.jar com/example/model/BeerExpert.java com/example/web/BeerSelect.java
5) move the class files (manually) from the src subdirectories into the classes subdiretories

I tried this successfully. This time with a real Servlet class.

Good luck.

[Vaibhav Jaiswal]

instead of this
cd ~/MyProject/beerV1
javac -d classes src/com/example/web/BeerSelect.java

try out
cd ~/MyProject/beerV1/src
javac -d classes -cp ../classes com/example/web/BeerSelect.java

For the error in the first post

[B Crosthwaite]

Hey Rienhard, Campbell and Vaibhav,

Thanks for all your replys.

Rienhard your steps worked for me, thank you.

-Ben

[Reinhard Horn]

This might be the better solution:

javac -classpath /Library/Tomcat/Home/lib/servlet-api.jar:.
-d classes src/com/example/web/BeerSelect.java
src/com/example/model/BeerExpert.java

Must be execute in beerV1.

[Campbell Ritchie]

Well done