servlet que son los servlet
DESCRIPTION
ejemplo javaTRANSCRIPT
Servlet que son los servlet
SERVLETS
PROFESOR : SANTIAGO MOQUILLAZA HENRIQUEZque son los servlet?
INDEX.JSP
JSP Page
Ejemplo Servlets - JDBC
Codigo
Alumno
Mostrar Alumnos
Dentro de Source Packages se crea el paquete cinfo.servlets
Y dentro de estos paquetes se crea la clase Consulta.java
Su codigo es:
package cinfo.servlets;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
public class Consulta extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Connection conn = obtenerConexion();
Statement st = null;
ResultSet rs= null;
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try{
st = conn.createStatement();
} catch(Exception e) {
out.print(e.toString());
}
try{
rs = st.executeQuery("select * from alumnos");
} catch(Exception e) {
out.println("No se pudo procesar la sentencia SQL");
out.println(e.toString());
}
try{
out.println("");
System.out.println("");
out.println("Servlet Consulta");
out.println("");
out.println("");
out.println("");
out.println("");
System.out.println("CodigoNombre");
while(rs.next()) {
out.println(""+rs.getInt(1)+""+ rs.getString(2)+"");
}
out.println("");
out.println("regresar");
out.println("");
out.println("");
} catch(Exception e) {
out.println("No se pudo mostrar la informacion");
out.println(e.toString());
}
out.close();
}
public Connection obtenerConexion() {
Connection cx = null;
try{
Class.forName("com.mysql.jdbc.Driver");
cx = DriverManager.getConnection("jdbc:mysql://localhost/alumnos","root","123");
} catch(Exception e) {
System.out.println(e.toString());
// e.printStackTrace();
}
return cx;
}
Tambin dentro de cinfo.servlets
Su cdigo de Inserta .java es :
package cinfo.servlets;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
public class Inserta extends HttpServlet {
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
Connection conn = obtenerConexion();
// Statement st = null;
ResultSet rs= null;
response.setContentType("text/html;charset=UTF-8");
// PrintWriter out = response.getWriter();
try{
// st = conn.createStatement();
} catch(Exception e) {
out.print(e.toString());
}
try{
int codigot = Integer.parseInt(request.getParameter("id"));
String nombret =request.getParameter("alum");
// insert into tabla(nombre,edad,estatura) values('juan', 15, 1.88);
//String q="insert into alumnos(codigo,nombre) values(\"" +codigot+"\","+nombret+");";
PreparedStatement st=conn.prepareStatement ("insert into alumnos(codigo,nombre)"+"values(?,?)");
//PreparedStatement stmt1 = conn.prepareStatement("INSERT INTO alumnos (idAlumno, Apellidos)"
// + "VALUES (?,?)");
st.setInt(1,codigot);
st.setString(2, nombret);
//
int n=st.executeUpdate();
//avisando que se hizo la instruccion
out.println("REGISTRO INSERTADO");
} catch(Exception e) {
out.println("No se pudo procesar la sentencia SQL");
out.println(e.toString());
}
//
out.close();
}
public Connection obtenerConexion() {
Connection cx = null;
try{
Class.forName("com.mysql.jdbc.Driver");
cx = DriverManager.getConnection("jdbc:mysql://localhost/alumnos","root","123");
} catch(Exception e) {
System.out.println(e.toString());
// e.printStackTrace();
}
return cx;
}
Tambin dentro de cinfo.servlets , la clase Notas.javapackage cinfo.servlets;
import java.io.*;
import java.net.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.sql.*;
/**
*
* @author SANTIAGO * @version
*/
public class Notas extends HttpServlet {
/** Processes requests for both HTTP GET and POST methods.
* @param request servlet request
* @param response servlet response
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Connection conn = obtenerConexion();
Statement st = null;
ResultSet rs= null;
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
out.println("");
out.println("");
out.println("Servlet Notas");
out.println("");
out.println("");
out.println("");
out.println("");
out.println("Nota");
try{
st = conn.createStatement();
} catch(Exception e) {
out.print(e.toString());
}
try{
rs = st.executeQuery("select nota from notas where idalumno="+request.getParameter("id"));
// rs = st.executeQuery("select nota from notas");
} catch(Exception e) {
out.println("No se pudo procesar la sentencia SQL");
out.println(e.toString());
}
try{
while(rs.next())
//out.println(""+rs.getString(1)+"");
out.println(""+rs.getInt(1)+"");
}
catch(Exception e) {
out.println("No se pudo mostrar la informacion");
out.println(e.toString());
}
out.println("");
out.println("regresar");
out.println("");
out.println("");
out.close();
}
public Connection obtenerConexion() {
Connection cx = null;
try{
Class.forName("com.mysql.jdbc.Driver");
cx = DriverManager.getConnection("jdbc:mysql://localhost/alumnos","root","123");
} catch(Exception e) {
System.out.println(e.toString());
//e.printStackTrace();
}
return cx;
}