DataBases and SQL INFSY 547 Spring 2007. Course Wrap Up April 12: Complete Work on Servlets Review...
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Transcript of DataBases and SQL INFSY 547 Spring 2007. Course Wrap Up April 12: Complete Work on Servlets Review...
DataBases and SQL
INFSY 547Spring 2007
Course Wrap Up
• April 12: Complete Work on Servlets
Review of Team Projects
Close of Portfolio Work• April 19: Review Form ideas, Team
Meetings and presentation
guidelines• April 26: Project Due Date
Develop presentations• May 3: Final Presentation and Party
Servlet Processing
Process a database (similar to an .xml file) Output an .html file Interact with Oracle via a servlet
In SQL Plus
Lab 10: Start with Eclipse
Create a project in Eclipse – (Infsy547OracleCustomerLab.java)
External .jar files
• classes12.jar• servlet-api.jar
Lab 10: Start with Eclipse
Create a package – infsy547oraclecustomerlab Create a class – by the same name as the project Add import statements
import java.io.*;import java.sql.*; import javax.servlet.*;import javax.servlet.http.*;
Servlet Assuming Names Table
public class Infsy547OracleCustomer extends HttpServlet
{private Connection connection;private PreparedStatement insertRecord;
private int acctNumber;<add string name, address, city, state>private PrintWriter out;
Names
acctNumber* name address city state
public void init( ServletConfig config ) throws ServletException { <call getConnected method> }
private void getConnected (){ try { Class.forName( "oracle.jdbc.driver.OracleDriver" ); connection = DriverManager.getConnection ("jdbc:oracle:thin: @146.186.84.66:1521:CLDB", “<userid>",“<psword>"); // PreparedStatement to add a customer record to names table insertRecord = connection.prepareStatement ( "INSERT INTO names (name, address, city, state, accountnumber) " + "VALUES(?, ?, ?, ?, ?)"); } catch(ClassNotFoundException cnf) {
System.err.println(cnf.getMessage());cnf.printStackTrace(); }
catch (SQLException sqlex) {System.err.println(sqlex.getMessage());sqlex.printStackTrace(); }
}
Loads the driver for Oracle
protected void doPost( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException {// set up response to client
response.setContentType( "text/html" ); out = response.getWriter();
// start XHTML documentout.println( "<?xml version = \"1.0\"?>" );out.println( "<!DOCTYPE html PUBLIC \"-//W3C//DTD " + "XHTML 1.0 Strict//EN\" \"http://www.w3.org" +
"/TR/xhtml1/DTD/xhtml1-strict.dtd\">" ); out.println("<html xmlns = \"http://www.w3.org/1999/xhtml\">" );
// head section of documentout.println( "<head>" ); acctNumber = Integer.parseInt(request.getParameter("accountNumber"));name = request.getParameter("Name");<write code to request the other necessary parameters><call a method, insertRecord>out.println( "<title>Thank you!</title>" );out.println( "</head>" );
out.println( "<body>" ); out.println( "<p>Thank you for adding your record." );out.println( "</pre></body></html>" ); out.close(); }
public void insertRecord (){ try {// update total for current survey response
insertRecord.setString( 1, name );insertRecord.setString( 2, address );<insert the city and state>insertRecord.setInt( 5, acctNumber);insertRecord.executeUpdate();
} catch ( SQLException sqlException ) { sqlException.printStackTrace(); out.println( "<title>Error</title>" ); out.println( "</head>" ); out.println( "<body><p>Database error occurred. " ); out.println( "Try again later.</p></body></html>" ); out.close(); }}
Note: Will not complete the html on previous page if this occurs.
@Overridepublic void destroy(){// attempt to close statements and database connection try
{ insertRecord.close(); connection.close();}
catch( SQLException sqlException ) {
sqlException.printStackTrace();}
} // end of destroy method
● Exceptions represent error conditions● Exceptions isolate the code that deals with error situations● Throwing: the act of detecting an abnormal condition
Searches for a handler catches the exception
● Try Block: Encloses one or more java statements
Exception Terminology
HTML<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>Insert Customer</title><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"></head><body><?xml version="1.0" encoding="iso-8859-1"?><form method = "post" action = "servlet/Infsy547OracleCustomerLab">
<label>Account Number</label><input name="accountNumber" type="text"><br><br><do the same for the remainder of the variables><br/><br/><input name="Save" type="submit" value="Save">
</form></body></html>
Complete
• Place files appropriately in TomCat structure
• Add to web.xml
• Start TomCat
• Start you servlet
• .java file from this lab– uploaded to the DataBase
Connectivity Drop Box – In ANGEL under the Lessons Tab
• .html file– Upload into HTML Drop Box
