// The class dbtest has two functionalities: servlet and JSP-compliant bean.
// When it is installed in a servlet-compatible Web server such as Java Web
// Server or Jigsaw, it acts as a servlet. The entry point is service().
//
// dbtest is also a server-side JavaBeans component. When it is installed
// in an environment where Java Server Pages is supported, it acts as a
// JSP-compatible bean. A JSP page can use this bean to access a database.
package test;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.net.*;
import java.sql.*;
public class dbtest extends HttpServlet implements SingleThreadModel
{
// from basic.java
Connection db; // The connection to the database
Statement st; // Our statement to run queries with
// internal stuff ---------------------
private Connection _connection;
private String _error = null;
// bean properties -----------------------------------------------
private boolean _connected = false;
private String _username = null;
private String _password = null;
// property - connected
public boolean getConnected() { return _connected; }
public void setConnected(boolean on)
{
if (on == _connected) return; // already in the requested state
if (on)
{
System.out.println("dbtest.connect: called");
try {
Class.forName("postgresql.Driver");
_connection = DriverManager.getConnection
("jdbc:postgresql:webdb", "postgres", "postgres");
_connected = on;
}
catch (Exception e)
{
_error = "dbtest.connect: " + e;
System.out.println(_error);
}
}
else // off
{
System.out.println("dbtest.disconnect: called");
try
{
_connection.close();
_connected = on;
}
catch (Exception e)
{
_error = "dbtest.disconnect: " + e;
System.out.println(_error);
}
}
}
// property - username
public String getUsername() { return _username; }
public void setUsername(String username) { _username = username; }
// property - password
public String getPassword()
{
if (_connected == false || _username == null) return null;
try
{
System.out.println("dbtest.query: called");
Statement stmt = _connection.createStatement();
ResultSet rs = stmt.executeQuery
("select * from club_y where c_name = '" + _username + "'");
if (rs.next()) _password = rs.getString(2); else _password = null;
rs.close();
stmt.close();
}
catch (Exception e)
{
_error = "dbtest.query: " + e;
System.out.println(_error);
_password = null;
}
return _password;
}
public void setPassword() {} // dummy
// servlet entry ---------------------------------------------------
public void service(HttpServletRequest req, HttpServletResponse res)
throws IOException
{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
out.println("dbtest servlet");
String username = req.getParameterValues("username")[0];
out.println("Searching email address for " + username + " ...");
setConnected(true);
if (getConnected())
{
setUsername(username);
String c_email = getPassword();
if (c_email == null) out.println("Not found
");
else out.println("email address is " + c_email + "
");
setConnected(false);
}
if (_error != null) out.println("ERROR: " + _error + "
");
out.println("");
out.flush();
}
}