Hi all,



I am learning JSP by first working on applications that run on my standalone computer at home. That is as far as I have gotten so far. The error: "Unable to compile class for JSP" is causing me great frustration. I have successfully installed Jakarta-Tomcat-4.1.24, Java (j2sdk1.4.1_01), the JDBC driver "com.mysql.jdbc.Driver". I have created and interacted with a MySQL(4.0.16) database successfully by running by running other Java applications that did things like add and delete recors so that part isn't a problem. Now I venture into the area of Beans. This is my first attempt and it has got me stuck. Any help is going to keep me from losing more sleep:).



I saved a file called Books.java in C:jakarta-tomcat-4.1.24webapps egjsp-ch16web-infclassescomwroxdatabases. I also saved five files called add.jsp, booklist.jsp, delete.jsp, error.jsp, and newbook.jsp to C:jakarta-tomcat-4.1.24webapps egjsp-ch16. I then went to my DOS prompt and compiled Books.java which created the Book.class file. I copied Book.class to C:jakarta-tomcat-4.1.24webapps egjsp-ch16web-inflib which I got from someone else. I am not sure if this part is correct.



I then went to my Internet Explorer and tried to access this page: http://localhost:8080/begjsp-ch16/booklist.jsp. This is where I get the error below. I did go to the tomcat site and try their examples to make sure JSP was working.



=========
HTTP Status 500 - type Exception report



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: -1 in the jsp file: null

Generated servlet error:
[javac] Since fork is true, ignoring compiler setting.
[javac] Compiling 1 source file
[javac] Since fork is true, ignoring compiler setting.
[javac] C:jakarta-tomcat-4.1.24workStandalonelocalhost egjsp-ch16 ooklist_jsp.java:10: package com.wrox.databases does not exist
[javac] import com.wrox.databases.*;
[javac] ^
[javac] C:jakarta-tomcat-4.1.24workStandalonelocalhost egjsp-ch16 ooklist_jsp.java:46: package com.wrox.databases does not exist
[javac] com.wrox.databases.Books book = null;
[javac] ^
[javac] C:jakarta-tomcat-4.1.24workStandalonelocalhost egjsp-ch16 ooklist_jsp.java:48: package com.wrox.databases does not exist
[javac] book = (com.wrox.databases.Books) pageContext.getAttribute("book", PageContext.PAGE_SCOPE);
[javac] ^
[javac] C:jakarta-tomcat-4.1.24workStandalonelocalhost egjsp-ch16 ooklist_jsp.java:51: package com.wrox.databases does not exist
[javac] book = (com.wrox.databases.Books) java.beans.Beans.instantiate(this.getClass().getClassLoader(), "com.wrox.databases.Books");
[javac] ^
[javac] 4 errors


=========



Books.java looks like this:


=========

			

			package com.wrox.databases;
			

			

			import java.sql.*;
			

			import java.util.*;
			

			

			public class Books {
			

			

			String error;
			

			Connection con;
			

			

			public Books() { }
			

			

			public void connect() throws ClassNotFoundException,
			

			SQLException,
			

			Exception {
			

			try {
			

			Class.forName("com.mysql.jdbc.Driver").newInstance();
			

			con = DriverManager.getConnection(
			

			"jdbc:mysql://localhost/Wrox?user=root&password=");
			

			} catch (ClassNotFoundException cnfe) {
			

			error = "ClassNotFoundException: Could not locate DB driver.";
			

			throw new ClassNotFoundException(error);
			

			} catch (SQLException cnfe) {
			

			error = "SQLException: Could not connect to database.";
			

			throw new SQLException(error);
			

			} catch (Exception e) {
			

			error = "Exception: An unknown error occurred while connecting " +
			

			"to database.";
			

			throw new Exception(error);
			

			}
			

			}
			

			

			public void disconnect() throws SQLException {
			

			try {
			

			if ( con != null ) {
			

			con.close();
			

			}
			

			} catch (SQLException sqle) {
			

			error = ("SQLException: Unable to close the database connection.");
			

			throw new SQLException(error);
			

			}
			

			}
			

			

			public ResultSet viewBooks() throws SQLException, Exception {
			

			ResultSet rs = null;
			

			try {
			

			String queryString = ("SELECT * FROM Book;");
			

			Statement stmt = con.createStatement();
			

			rs = stmt.executeQuery(queryString);
			

			} catch (SQLException sqle) {
			

			error = "SQLException: Could not execute the query.";
			

			throw new SQLException(error);
			

			} catch (Exception e) {
			

			error = "An exception occured while retrieving books.";
			

			throw new Exception(error);
			

			}
			

			return rs;
			

			}
			

			

			public void addBooks(int id, String title, float price, int cid)
			

			throws SQLException, Exception {
			

			if (con != null) {
			

			try {
			

			PreparedStatement updatebooks;
			

			updatebooks = con.prepareStatement(
			

			"insert into Book values(?, ?, ?, ?);");
			

			updatebooks.setInt(1, id);
			

			updatebooks.setString(2, title);
			

			updatebooks.setInt(3, cid);
			

			updatebooks.setFloat(4, price);
			

			updatebooks.execute();
			

			} catch (SQLException sqle) {
			

			error = "SQLException: update failed, possible duplicate entry";
			

			throw new SQLException(error);
			

			}
			

			} else {
			

			error = "Exception: Connection to database was lost.";
			

			throw new Exception(error);
			

			}
			

			}
			

			

			public void removeBooks(String [] pkeys) throws SQLException, Exception {
			

			if (con != null) {
			

			try {
			

			PreparedStatement delete;
			

			delete = con.prepareStatement("DELETE FROM Book WHERE Title_ID=?;");
			

			for (int i = 0; i
			< pkeys.length; i++) {
			

			delete.setInt(1, Integer.parseInt(pkeys));
			

			delete.execute();
			

			}
			

			} catch (SQLException sqle) {
			

			error = "SQLException: update failed, possible duplicate entry";
			

			throw new SQLException(error);
			

			} catch (Exception e) {
			

			error = "An exception occured while deleting books.";
			

			throw new Exception(error);
			

			}
			

			} else {
			

			error = "Exception: Connection to database was lost.";
			

			throw new Exception(error);
			

			}
			

			}
			

			}
			

		

			

			=========
			

			<%@ page language="java"
			

			import="java.sql.*, java.io.*, java.util.*, com.wrox.databases.*"
			

			errorPage="error.jsp" %>
			

			

			

			

			

			

			

			

			

			

			
Wrox Press Ltd.
			

			
List of Books
			

			

			
				Add More Books
			
			

			

			
				

				

				

				

				

				

				

				

				<%
				

				book.connect();
				

				ResultSet rs = book.viewBooks();
				

				while (rs.next()) {
				

				%>
				

				

				

				

				

				

				

				

				<%
				

				}
				

				%>
				

				

				

					

						

							

								ID:
							
							

								Title:
							
							

								Price:
							
						
						

							

								

								
								

								value="
								<%= rs.getString("Title_ID") %>" />
								

							
							
<%= rs.getString("Title") %>
							
<%= rs.getString("Price") %>
						
					
				
				

				

				

				Check books for deletion.
				

				

				
				

			
			

			

			<% book.disconnect(); %>