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For 2023 (and 2024 ...) - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
JSP, Servlets and MySQL / David Harms

Posted by admin (Graham Ellis), 4 September 2002
Good book; nice to see someone covering server side Java and MySQL in the same text.  Full details at:
http://www.wellho.net/book/0-7645-4787-9.html

Caution: The web site address that the books give for source download doesn't work, and I don't know of any alternative.  Think that others have the same problem as I regularly get emails asking - and I'm not even anything to do with the author or publisher!

Addendum - January 2003 See extra post at the end of the thread - we have an alternative live URL for the book source ...
April 2003 Alternative URL no longer operational.  

Posted by admin (Graham Ellis), 4 September 2002
Here's an  example from one of our training courses, which is a single servlet class that generates a forms, and also calls both the insert and the select queries.  It includes only one explicit reference to each field name making it very easy to change in the future.

Code:
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

/*
* General class for inserting and reporting on a table
*/

public class J850staff extends HttpServlet {

   public void doGet(HttpServletRequest request,
                     HttpServletResponse response)
       throws IOException, ServletException
   {
   String action = "Unselected";
   try {
   action = request.getParameter("action");
   } catch (Exception e) {
   }
   if (action == null) action = "Unselected";

   String [] fields = {"name","job","office","hometown","title"};
   String reply = "";

   if (action.equals("Unselected")) {
   reply = "Hello and Welcome";
   } else if (action.startsWith("Insert")) {
   reply = runInsert(fields,request);
   } else if (action.startsWith("Select")) {
   reply = runSelect(fields,request);
   } else {
   reply = "Corrupt form";
   }

   reply = reply + "<BR><HR><BR>" + getForms(fields);

       response.setContentType("text/html");
       PrintWriter out = response.getWriter();

       out.println(reply);

   }

String runInsert (String [] fields,HttpServletRequest request) {

   StringBuffer fnames = new StringBuffer("");
   StringBuffer fvals = new StringBuffer("");

   for (int i=0; i<fields.length; i++) {
   String called = request.getParameter(fields[i]);
   if (i>0) fnames.append(", ");
   fnames.append(fields[i]);
   if (i>0) fvals.append(", ");
   fvals.append("'"+called+"'");
   }

   J850sjdbc.insert(fnames.toString(), fvals.toString());

   return ("Insertion Done");

   }

String runSelect (String [] fields,HttpServletRequest request) {

   StringBuffer fselect = new StringBuffer("where ");

   for (int i=0; i<fields.length; i++) {
   String called = request.getParameter(fields[i]);

   if (! called.equals(""))
   {
   if (fselect.length() > 6) {
   fselect.append(" && ");
   }
   fselect.append (fields[i] + " = '" +
   called +"' ");
   }
   }
   if (fselect.length() <= 6) {
   fselect = new StringBuffer("");
   }

   return (J850sjdbc.select(fields, fselect.toString()));

}

String getForms (String [] fields) {

   StringBuffer insert = new StringBuffer("<table border=1>");

   for (int i=0; i<fields.length; i++) {
   insert.append("<tr><td>"+fields[i]+"</td><td><input name="+
   fields[i]+"></td></tr>");
   }

   insert.append("<tr><td>then ..</td><td>"+
   "<input type=submit name=action value=Insert>"+
   "<input type=submit name=action value=Select>"+
   "</td></tr></table>");

   return ("<form>"+insert.toString()+"</form>");
   }
}


Here's the source code of that class that references the SQL database:

Code:
public class J850sjdbc {

public static String insert(String names, String values) {

   java.sql.Connection conn = linktodata();

   String todo = ("INSERT into staff " +
   "(" + names + ") values (" + values + ")");

   try {
   java.sql.Statement s = conn.createStatement();
   int r = s.executeUpdate (todo);
   }
   catch (Exception e) {
   return ("Oh oops - code 003\n"+e);
   }
       return (todo);
   }

public static String select(String [] fields, String selector) {

   java.sql.Connection conn = linktodata();

   StringBuffer reply = new StringBuffer("<table border=1>");

   String todo = ("SELECT * "+
   " from staff " + selector);

   try {
   java.sql.Statement s = conn.createStatement();
   java.sql.ResultSet r = s.executeQuery (todo);
   while(r.next()) {
   reply.append("<tr>");
   for (int i=0;i<fields.length;i++) {
   reply.append(tabit(r.getString(fields[i])));
   }
   reply.append("</tr>");
   }
   reply.append("</table>");
   }
   catch (Exception e) {
   return ("Oh oops - code 003\n"+e);
   }

   return (reply.toString());
       }

private static String tabit(String box) {
   return ("<td>"+box+"</td>");
   }

private static java.sql.Connection linktodata () {

   java.sql.Connection conn = null;
   try {
   Class.forName("org.gjt.mm.mysql.Driver").newInstance();
   }
   catch (Exception e) {
   return conn;
   // return "Oh dear - code 001 and a quarter";
   }
   try {
   conn = java.sql.DriverManager.getConnection(
   "jdbc:mysql://bhajee/J850a?user=jtest&password=");
   }
   catch (Exception e) {
   return conn;
   // return "Oh dear - code 001 and a half";
   }
   return conn;
}
}



Posted by admin (Graham Ellis), 27 January 2003
Alternative URL for the book (this one works as of the date that I'm posting )

http://www.covecomm.com/index.html

Posted by admin (Graham Ellis), 22 April 2003
An update ... the URL in the previous post is no longer operational ... if anyone knows a fresh location, please let me know!



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