Untitled

//index.html
<!DOCTYPE html>
<html>
<head>
	<meta charset="UTF-8">
	<title>Students</title>
</head>

<body>
	<a href="list_students"> Lista studenti</a>
</body>
</html>


//list_students.jsp
<%@page import="java.util.LinkedList"%>
<%@page import="it.unipr.informatica.exercise4.model.Student"%>
<%@page import="java.util.List"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
	<title>List Students</title>
</head>

<body>
	<%
		List<Student> students = (List<Student>)session.getAttribute("list_students");
		if(students == null)
			students = new LinkedList<>();
	%>
	<table>
		<thead>
			<tr>
				<td>
					ID
				</td>
				<td>
					Last name
				</td>
				<td>
					First name
				</td>
			</tr>
		</thead>
		<tbody>
			<%
				for(Student student : students) {
			%>
			<tr>
				<td><a href="details?id=<%=student.getID()%>"><%=student.getID()%></a></td>
				<td> <%=student.getLastName() %> </td>
				<td> <%=student.getFirstName() %> </td>
			</tr>
			<%
				}
			%>
 		</tbody>
	</table>
</body>
</html>


//ListStudents.java
package it.unipr.informatica.exercise.web;

import it.unipr.informatica.exercise4.database.DatabaseManager;
import it.unipr.informatica.exercise4.model.Student;
import java.io.IOException;
import java.util.List;
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 javax.servlet.http.HttpSession;

@SuppressWarnings("serial")
@WebServlet("/list_students")
public class ListStudents extends HttpServlet {

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			HttpSession session = request.getSession();
			DatabaseManager DBmanager = (DatabaseManager)session.getAttribute("DB_manager");

			if(DBmanager == null) {
				DBmanager = new DatabaseManager();
				session.setAttribute("DB_manager", DBmanager);
			}

			List<Student> students = DBmanager.getAllStudent();
			session.setAttribute("list_students", students);

			request.getRequestDispatcher("list_students.jsp").forward(request, response);
		} catch(Throwable t) {
			t.printStackTrace();
			request.getRequestDispatcher("error.html").forward(request, response);
		}
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}


//Details.java
package it.unipr.informatica.exercise.web;

import it.unipr.informatica.exercise4.database.DatabaseManager;
import it.unipr.informatica.exercise4.model.Student;

import java.io.IOException;

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 javax.servlet.http.HttpSession;

@SuppressWarnings("serial")
@WebServlet("/details")
public class Details extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			String m = request.getParameter("id");
			int id = Integer.parseInt(m);
			HttpSession session = request.getSession();
			DatabaseManager DBmanager = (DatabaseManager)session.getAttribute("DB_manager");

			if(DBmanager == null) {
				DBmanager = new DatabaseManager();
				session.setAttribute("DB_manager", DBmanager);
			}
			Student student = DBmanager.getStudentByID(id);
			session.setAttribute("student", student);
			request.getRequestDispatcher("details_student.jsp").forward(request, response);
		} catch(Throwable t) {
			t.printStackTrace();

		}
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	}

}


//DatabaseManager.java
package it.unipr.informatica.exercise4.database;

import it.unipr.informatica.exercise4.model.FactoryModel;
import it.unipr.informatica.exercise4.model.Student;
import it.unipr.informatica.exercise4.model.implementation.FactoryModelImplementation;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.ResourceBundle;


public class DatabaseManager {
	private FactoryModel factory;
	private String url;

	public DatabaseManager() {
		createFactoryModel();
		ResourceBundle bundle = ResourceBundle.getBundle("configuration");
		url = bundle.getString("database.url");
		String driver = bundle.getString("database.driver");

		try{
			Class.forName(driver);
		} catch(Throwable t) {
			t.printStackTrace();
		}
	}

	protected void createFactoryModel() {
		factory = new FactoryModelImplementation();
	}

	public void setFactoryModel(FactoryModel factory) {
		this.factory = factory;
	}

	private Connection createConnection() throws SQLException {
		return DriverManager.getConnection(url);
	}

	private void disconnect(Connection c, Statement s) {
		disconnect(c, s, null);
	}

	private void disconnect(Connection c, Statement s, ResultSet r) {
		try {
			r.close();
		} catch(Throwable t){}

		try {
			s.close();
		} catch(Throwable t){}

		try {
			c.close();
		} catch(Throwable t){}
	}

	public Student addStudent(String lastName, String firstName) throws SQLException{
		Connection c = null;
		PreparedStatement s = null;
		ResultSet r = null;
		Student res = null;
		try {
			c = createConnection();
			s = c.prepareStatement("INSERT INTO STUDENT(lastName, firstName) VALUES (?, ?)", Statement.RETURN_GENERATED_KEYS);
			s.setString(1, firstName);
			s.setString(2, lastName);
			s.execute();
			r = s.getGeneratedKeys();
			r.next();

			int id = r.getInt(1);
			res = factory.newStudent(id, lastName, firstName);

		} catch(SQLException e) {
			disconnect(c, s, r);
			throw e;
		}
		disconnect(c, s);
		return res;
	}

	public List<Student> getAllStudent() throws SQLException {
		Connection c = null;
		PreparedStatement s = null;
		ResultSet r = null;
		List<Student> res = new ArrayList<Student>();

		try {
			c = createConnection();
			s = c.prepareStatement("SELECT * FROM STUDENT");
			r = s.executeQuery();

			while(r.next()) {
				int id = r.getInt("ID");
				String lName = r.getString("lastName");
				String fName = r.getString("firstName");

				Student student = factory.newStudent(id, lName, fName);
				res.add(student);
			}
		} catch(SQLException e) {
			disconnect(c, s, r);
			throw e;
		}

		disconnect(c, s, r);
		return res;
	}

	public Student getStudentByID(int id) throws SQLException {
		Connection c = null;
		PreparedStatement s = null;
		ResultSet r = null;
		Student res = null;

		try {
			c = createConnection();
			s = c.prepareStatement("SELECT * FROM STUDENT WHERE = ?");
			s.setInt(1, id);
			r = s.executeQuery();

			if(r.next()) {
				String lName = r.getString("lastName");
				String fName = r.getString("firstName");

				res = factory.newStudent(id, lName, fName);
			}
		} catch(SQLException e) {
			disconnect(c, s, r);
			throw e;
		}

		disconnect(c, s, r);
		return res;
	}
}


//error.html
<!DOCTYPE html>
<html>
<head>
	<meta charset="UTF-8">
	<title>Information not found</title>
</head>
<body>
	<h1>Information not found in the DB</h1>
</body>
</html>


//details.student.jsp
<%@page import="java.util.LinkedList"%>
<%@page import="it.unipr.informatica.exercise4.model.Student"%>
<%@page import="java.util.List"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
	<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
	<title>Details student</title>
</head>

<body>
	<%
		Student student = (Student)session.getAttribute("details_student");
		if(student == null)
			//student = new Student;
	%>
	<p> <%=student.getID()%></p>
	<p> <%=student.getLastName() %> <p>
	<p> <%=student.getFirstName() %> <p>
</body>
</html>