Un código en Java con Servlet conectado a un majeador de base de datos en este caso Oracle
import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.sql.*;
@WebServlet(name = "Datos", urlPatterns = {"/Datos"}) public class Datos extends HttpServlet { Connection conexion; Statement st; ResultSet rs; String ruta ="jdbc:oracle:thin:@localhost:1521:XE"; String usuario = "CONSTANTE"; String id1,ed,pass="ska";
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
String usuari = request.getParameter("user");
Class.forName("oracle.jdbc.driver.OracleDriver");
conexion = DriverManager.getConnection (ruta, usuario, pass);
st = (Statement) conexion.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
String min = "select * from \"Datos1\" WHERE USUARIO = '"+usuari+"'";
rs = st.executeQuery(min);
while (rs.next()) {
String nomb = rs.getString(1);
String usr= rs.getString(2);
//String pass = rs.getString(3);
String ent= rs.getString(4);
String cor= rs.getString(5);
String con = request.getParameter("pass");
if(usuari.compareTo(usr)==0 && con.compareTo(pass)==0)
{
if(ent.compareTo("MAESTRO")==0)
{
out.println("<html>");
out.println("<head>");
out.println(" <title>Plataforma UVQ</title>");
out.println("<link rel='stylesheet' type='text/css' href='plat.css' />");
out.println("<meta http-equiv='Content-Type' content='text/html' charset='UTF-8'>");
out.println("<LINK REL='SHORTCUT ICON' HREF='favicon.ico'>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Hola "+ent+" "+nomb+"</h1>");
out.println("<h1>Clases Pendientes</h1>");
String m= "select * from \"CLASES\" WHERE "+ent+" = '"+nomb+"'";
rs = st.executeQuery(m);
while (rs.next()) {
String tem = rs.getString(1);
String obj= rs.getString(2);
String hi = rs.getString(3);
String hf= rs.getString(4);
String ta= rs.getString(5);
String fe= rs.getString(6);
String ma = rs.getString(7);
String es= rs.getString(8);
out.println("<h1>Tema: " +tem + "</h1>");
out.println("<h1>Objetivo: " +obj + "</h1>");
out.println("<h1>Hora Inicio: " +hi + "</h1>");
out.println("<h1>Hora Final: " +hf + "</h1>");
out.println("<h1>Tarea: " +ta+ "</h1>");
out.println("<h1>Fecha: " +fe + "</h1>");
out.println("<h1>Maestro: " +ma + "</h1>");
out.println("<h1>Estudiante:" +es + "</h1>");
out.println("</body>");
out.println("</html>");
}
out.println("<html>");
out.println("<head>");
out.println("<title>Plataforma UVQ</title>");
out.println("<link rel='stylesheet' type='text/css' href='plat.css' />");
out.println("<meta http-equiv='Content-Type' content='text/html' charset='UTF-8'>");
out.println("<LINK REL='SHORTCUT ICON' HREF='favicon.ico'>");
out.println("</head>");
out.println("<h1>Registrar Clase</h1>");
out.println("<form method='post' action='Clase' name='form'>");
out.println("<table id='ta' >");
out.println("<tr>");
out.println("<td>Tema :</td>");
out.println(" <td><input name='tema' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Objetivo:</td>");
out.println(" <td><input name='obj' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Hora de Inicio :</td>");
out.println(" <td><input name='horaini' id='form_time' type='time' /> </td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Hora Final :</td>");
out.println(" <td><input name='horafin' id='form_time' type='time' required /> </td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Tarea :</td>");
out.println(" <td><input name='tarea' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Fecha:</td>");
out.println(" <td><input name='fecha' id='form_date' type='date' required /></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Mestro :</td>");
out.println(" <td><input name='mae' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Estudiante :</td>");
out.println(" <td><input name='est' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("</table>");
out.println("<input type='submit' value='Registrar Clase' id='submit'/>");
out.println("</form>");
out.println("</body>");
out.println("</html>");
}
else{
out.println("<html>");
out.println("<head>");
out.println(" <title>Plataforma UVQ</title>");
out.println("<link rel='stylesheet' type='text/css' href='plat.css' />");
out.println("<meta http-equiv='Content-Type' content='text/html' charset='UTF-8'>");
out.println("<LINK REL='SHORTCUT ICON' HREF='favicon.ico'>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Hola "+ent+" "+nomb+"</h1>");
out.println("<h1>Clases Pendientes</h1>");
String m= "select * from \"CLASES\" WHERE "+ent+" = '"+nomb+"'";
rs = st.executeQuery(m);
while (rs.next()) {
String tem = rs.getString(1);
String obj= rs.getString(2);
String hi = rs.getString(3);
String hf= rs.getString(4);
String ta= rs.getString(5);
String fe= rs.getString(6);
String ma = rs.getString(7);
String es= rs.getString(8);
out.println("<h1>Tema: " +tem + "</h1>");
out.println("<h1>Objetivo: " +obj + "</h1>");
out.println("<h1>Hora Inicio: " +hi + "</h1>");
out.println("<h1>Hora Final: " +hf + "</h1>");
out.println("<h1>Tarea: " +ta+ "</h1>");
out.println("<h1>Fecha: " +fe + "</h1>");
out.println("<h1>Maestro: " +ma + "</h1>");
out.println("<h1>Estudiante:" +es + "</h1>");
out.println("</body>");
out.println("</html>");
}
}
}
else{
out.println("<html>");
out.println("<title>login</title>");
out.println("<body>");
out.println("<h1>No estas registrado, Registrate!!/h1>");
out.println("<form method='post' action='Alta' name='form'>");
out.println("<table id='ta' >");
out.println("<tr>");
out.println("<td>Entidad :</td>");
out.println("<input type='radio' value='MAESTRO' name='ocupacion'>Maestro<br>");
out.println("<input type='radio' value='ESTUDIANTE' name='ocupacion'>Estudiante<br>");
out.println("</td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Nombre :</td>");
out.println(" <td><input name='nom' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Usuario :</td>");
out.println(" <td><input name='user' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Contraseña :</td>");
out.println(" <td><input name='pass' type='password' size='20' required/></td>");
out.println("</tr>");
out.println("<tr>");
out.println("<td>Correo :</td>");
out.println(" <td><input name='correo' type='text' size='20' required /></td>");
out.println("</tr>");
out.println("</table>");
out.println("<input type='submit' value='Registrarse' id='submit'/>");
out.println("</form>");
out.println("</body>");
out.println("</html>");
}
}
}
catch (ClassNotFoundException e1) {
out.println("ERROR:No encuentro el driver de la BD: "+
e1.getMessage());
}
catch (SQLException e2) {
//Error SQL: login/passwd mal
out.println("ERROR:Fallo en SQL: "+e2.getMessage());
}
finally {
try {
if (conexion!=null)
conexion.close();
} catch (SQLException e3) {
out.println("ERROR:Fallo al desconectar de la BD: "+
e3.getMessage());
}
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP
* <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP
* <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}