koszyk i sesja

PC24-SklepWeb/src/main/java/sklep/basket/AddToBasket.java

+package sklep.basket;
+
+import java.io.IOException;
+
+import jakarta.servlet.ServletException;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jakarta.servlet.http.HttpSession;
+import sklep.db.DBConnection;
+import sklep.db.ProductDAO;
+import sklep.model.Product;
+
+@WebServlet("/add_to_basket")
+public class AddToBasket extends HttpServlet {
+	private static final long serialVersionUID = 1L;
+
+	@Override
+	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+		try {
+			int productId = Integer.parseInt(request.getParameter("productId"));
+			try(DBConnection db = DBConnection.open()) {
+				ProductDAO productDAO = db.productDAO();
+				Product product = productDAO.findById(productId);
+				
+				HttpSession sesja = request.getSession();
+				Basket basket = (Basket)sesja.getAttribute("basket");
+				if(basket == null) {
+				    basket = new Basket();
+				    sesja.setAttribute("basket", basket);
+				}
+				basket.addProduct(product);
+			}
+		} catch(Exception e) {
+			// ignorujemy błędy
+		}
+		// Przekierowanie - każemy przeglądarce wejść pod ten adres.
+		response.sendRedirect("products8.jsp");
+	}
+
+}

PC24-SklepWeb/src/main/java/sklep/basket/Basket.java

+package sklep.basket;
+
+import java.math.BigDecimal;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import sklep.model.Product;
+
+public class Basket {
+	private final Map<Integer, ProductInBasket> elementy = new HashMap<>();
+	
+	public synchronized void addProduct(Product product, int quantity) {
+		if(elementy.containsKey(product.getProductId())) {
+			// jeśli w słowniku jest już taki element, to tylko zwiększamy ilość
+			elementy.get(product.getProductId()).increaseQuantity(quantity);
+		} else {
+			// jeśli jeszcze nie ma, to tworzymy
+			elementy.put(product.getProductId(),
+					new ProductInBasket(product.getProductId(), product.getProductName(), product.getPrice(), quantity));
+		}
+	}
+
+	public synchronized void addProduct(Product product) {
+		// "domyślną ilością, o którą zwiększamy, jest 1"
+		addProduct(product, 1);
+	}
+
+	
+	public synchronized Collection<ProductInBasket> getElements() {
+		return Collections.unmodifiableCollection(elementy.values());
+	}
+
+	public synchronized BigDecimal getTotalValue() {
+		return getElements().stream()
+				.map(ProductInBasket::getValue)
+				.reduce(BigDecimal.ZERO, BigDecimal::add);
+	}
+	
+	@Override
+	public synchronized String toString() {
+		return "Koszyk o rozmiarze " + getElements().size()
+				+ " i wartości " + getTotalValue();
+	}
+	
+}

PC24-SklepWeb/src/main/java/sklep/basket/ProductInBasket.java

+package sklep.basket;
+
+import java.math.BigDecimal;
+import java.util.Objects;
+
+public class ProductInBasket {
+	private int productId;
+	private String productName;
+	private BigDecimal price;
+	private int quantity;
+
+	public ProductInBasket(int productId, String productName, BigDecimal price, int quantity) {
+		this.productId = productId;
+		this.productName = productName;
+		this.price = price;
+		this.quantity = quantity;
+	}
+
+	public BigDecimal getPrice() {
+		return price;
+	}
+
+	public void setPrice(BigDecimal price) {
+		this.price = price;
+	}
+
+	public int getQuantity() {
+		return quantity;
+	}
+
+	public void setQuantity(int quantity) {
+		this.quantity = quantity;
+	}
+
+	public int getProductId() {
+		return productId;
+	}
+
+	public String getProductName() {
+		return productName;
+	}
+
+	@Override
+	public String toString() {
+		return "ElementKoszyka [productId=" + productId + ", productName=" + productName + ", price=" + price
+				+ ", quantity=" + quantity + "]";
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(price, productId, productName, quantity);
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		ProductInBasket other = (ProductInBasket) obj;
+		return Objects.equals(price, other.price) && productId == other.productId
+				&& Objects.equals(productName, other.productName) && quantity == other.quantity;
+	}
+
+	public BigDecimal getValue() {
+		return price.multiply(BigDecimal.valueOf(quantity));
+	}
+
+	public void increaseQuantity(int change) {
+		quantity += change;
+	}
+
+}

PC24-SklepWeb/src/main/webapp/products8.jsp

+<%@page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
+<%@taglib prefix="c" uri="jakarta.tags.core"%>
+
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="UTF-8">
+<title>Lista produktów 8</title>
+<link rel="stylesheet" type="text/css" href="styl.css">
+</head>
+<body>
+
+<div class="koszyk">
+<h4>Koszyk</h4>
+<ul>
+<%-- Zauważmy, że dla obiektu koszyk nie wykonujemy już useBean.
+     Po prostu zakładamy, że jest obecny (w sesji). Gdyby go nie było, to pętla się nie wykona. --%>
+<c:forEach var="elm" items="${basket.elements}">
+    <li>${elm.productName} (${elm.quantity}) za <b>${elm.value}</b></li>
+</c:forEach>
+</ul>
+<p class="total">Do zapłaty: ${basket.totalValue}</p>
+</div>
+
+<h1>Lista produktów - wersja 8</h1>
+
+<form id="wyszukiwarka" method="get">
+<h2>Filtr cen</h2>
+<table class="formularz">
+<tr><td><label for="min_price">Cena minimalna:</label></td>
+    <td><input type="number" name="min_price" value="${param.min_price}"></td></tr>
+<tr><td><label for="max_price">Cena maksymalna:</label></td>
+    <td><input type="number" name="max_price" value="${param.max_price}"></td></tr>
+<tr><td><button>Filtruj</button></td></tr>
+</table>
+</form>
+
+<jsp:useBean id="productBean" class="sklep.web.ProductBean"/>
+<jsp:setProperty name="productBean" property="minPrice" param="min_price"/>
+<jsp:setProperty name="productBean" property="maxPrice" param="max_price"/>
+
+<c:forEach var="product" items="${productBean.filteredProducts}">
+    <div class="product">
+		<img class="photo" src="photo?productId=${product.productId}" alt=""/>
+        <h3>${product.productName}</h3>
+        <div class="price">Cena: ${product.price}</div>
+        <div class="price">VAT ${p.vat * 100}%</div>
+        <c:if test="${not empty(product.description)}">
+            <p class="description">${product.description}</p>
+        </c:if>
+        <div class="action"><a href="add_to_basket?productId=${product.productId}">dodaj do koszyka</a></div>
+    </div>
+</c:forEach>
+
+</body>
+</html>