RICERCABIn J 2

 INDEX

<!DOCTYPE html>

<html>

<head>

<meta charset="utf-8">

<title>BinarySearch</title>

</head>

<body>

<form action="Prova" method="get">

<div align="center">

<label >Ricerca Binaria</label>

<input type="number" name="numeri" min ="0" required>

<input type="submit" name="Verifica" value="Verifica">

</div>

<div align="center">

</div>

</form>

<% if(request.getAttribute("risposta")!=null)   {%>

<p><%= request.getAttribute("risposta") %>

<% } %>

</body>

</html>


----------------------------------------------------------------------------------------

CLASSE MODEL


package it.cefi.models;


import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.List;

import java.util.Random;

public class Algoritmo {

private List<Integer> numeriCasuali = new ArrayList<>();

private int chiave;

public List<Integer> getNumeriCasuali() {

return numeriCasuali;

}

public void setNumeriCasuali(List<Integer> numeriCasuali) {

this.numeriCasuali = numeriCasuali;

} 

public Algoritmo(int chiave) {

Random random = new Random();

for (int i = 0; i < 50; i++) {

numeriCasuali.add( random.nextInt(50));

}

Collections.sort(numeriCasuali);

System.out.print(numeriCasuali.toString());

this.chiave= chiave;

}

public Algoritmo(List<Integer> numeriCasuali) {

super();

this.numeriCasuali = numeriCasuali;

}

public int ricercaBinaria( int first, int last) {

if (last>=first){  

int mid = first + (last - first)/2;  

if (numeriCasuali.get(mid) == chiave){  

return mid;  

}  

if (numeriCasuali.get(mid) > chiave){  

return ricercaBinaria( first, mid-1);  

}else{  

return ricercaBinaria( mid+1, last);  

}  

}  

return -1;  

}

public int getChiave() {

return chiave;

}

public void setChiave(int chiave) {

this.chiave = chiave;

}  

}


---------------------------------------------------------------------

SERVLET

ackage it.cefi.servlet;


import java.io.IOException;

import it.cefi.models.Algoritmo;

import jakarta.servlet.RequestDispatcher;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
@WebServlet("/Prova")
public class AlgoritmoServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
RequestDispatcher requestDispatcher = request.getRequestDispatcher("index.jsp");
Algoritmo algoritmo = new Algoritmo(Integer.parseInt(request.getParameter("numeri")));
int posizione = algoritmo.ricercaBinaria(0, algoritmo.getNumeriCasuali().size());
if(posizione == -1) {
request.setAttribute("risposta", "valore non trovato");
}else {
request.setAttribute("risposta",posizione );
}
requestDispatcher.forward(request, response);
}

}



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