Session的實現(xiàn)例子

2019-11-06 06:01:59

字體：大中小

供稿：網(wǎng)友

用session實現(xiàn)一個購物車

1.首先搭建web項目框架

目錄為：

2.再來看看web.xml的配置

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"	xmlns="http://java.sun.com/xml/ns/javaee"	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"	id="WebApp_ID" version="3.0">	<display-name>session</display-name>	<welcome-file-list>		<welcome-file>/jsp/bookChose.jsp</welcome-file>	</welcome-file-list>	<servlet>		<servlet-name>shoppingcar</servlet-name>		<servlet-class>session.SessionShoppingCarSevlet</servlet-class>	</servlet>	<servlet-mapping>		<servlet-name>shoppingcar</servlet-name>		<url-pattern>/SessionShoppingCarSevlet</url-pattern>	</servlet-mapping>	<servlet>		<servlet-name>shoppinglist</servlet-name>		<servlet-class>session.ShoppingCarListServlet</servlet-class>	</servlet>	<servlet-mapping>		<servlet-name>shoppinglist</servlet-name>		<url-pattern>/ShoppingCarListServlet</url-pattern>	</servlet-mapping></web-app>3.代碼的是實現(xiàn)
SessionShoppingCarSevlet.class
package session;import java.io.IOException;import java.util.HashMap;import java.util.Map;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;public class SessionShoppingCarSevlet extends HttpServlet {	PRivate static final long serialVersionUID = 1L;	@SuppressWarnings("unchecked")	@Override	protected void doPost(HttpServletRequest req, HttpServletResponse resp)			throws ServletException, IOException {		req.setCharacterEncoding("UTF-8");		resp.setContentType("text/html;charset = UTF-8");		// 獲取會話對象		HttpSession session = req.getSession();		// 從會話域中獲取shoppingCar屬性對象		// 定義key為書名，value為數(shù)量		Map<String, Integer> shoppingCar = (Map<String, Integer>) session				.getAttribute("shoppingCar");		if (null == shoppingCar) {			shoppingCar = new HashMap<String, Integer>();		}		String[] books = req.getParameterValues("book");		if (books != null && books.length > 0) {			for (String bookname : books) {				// 判斷書籍是否在購物車中				if (null == shoppingCar.get(bookname)) {					shoppingCar.put(bookname, 1);				} else {					shoppingCar.put(bookname, shoppingCar.get(bookname) + 1);				}			}		}		// 將更新后的購物車存儲在會話域中		session.setAttribute("shoppingCar", shoppingCar);		resp.sendRedirect("http://localhost:8080/SessionExampleServlet/ShoppingCarListServlet");	}}
ShoppingCarListServlet類package session;import java.io.IOException;import java.io.PrintWriter;import java.util.Map;import java.util.Map.Entry;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;public class ShoppingCarListServlet extends HttpServlet {	private static final long serialVersionUID = 1L;	@Override	protected void doGet(HttpServletRequest req, HttpServletResponse resp)			throws ServletException, IOException {		this.doPost(req, resp);	}	@SuppressWarnings("unchecked")	@Override	protected void doPost(HttpServletRequest req, HttpServletResponse resp)			throws ServletException, IOException {		req.setCharacterEncoding("UTF-8");		resp.setContentType("text/html;charset = UTF-8");		PrintWriter out = resp.getWriter();		HttpSession session = req.getSession();		Map<String, Integer> shoppingCar = (Map<String, Integer>) session				.getAttribute("shoppingCar");		if (shoppingCar != null && shoppingCar.size() > 0) {			out.print("<p>您購買的書籍有：</p>");			for (Entry<String, Integer> book : shoppingCar.entrySet()) {				out.print(book.getKey() + "---" + book.getValue() + "本");			}		} else {			out.print("您還沒有購買書籍");		}		out.print("<a href = 'http://localhost:8080/SessionExampleServlet/jsp/bookChose.jsp'>繼續(xù)購買書籍</a>");	}}4.bookChose.jsp代碼的實現(xiàn)<%@ page language="java" contentType="text/html; charset=UTF-8"	pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/htnl4/losse.dtd"><html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><title>書籍選購</title></head><body>	<h3>請選擇你的書籍</h3>	<form		action="http://localhost:8080/SessionExampleServlet/SessionShoppingCarSevlet"		method="post">		<p>			<input type="checkbox" name="book" value="javaSE 應用開發(fā)">javaSE			應用開發(fā)		</p>		<p>			<input type="checkbox" name="book" value="javaEE 應用開發(fā)">javaEE			應用開發(fā)		</p>		<p>			<input type="checkbox" name="book" value="javaWeb 應用開發(fā)">javaWeb			應用開發(fā)		</p>		<p>			<input type="submit" value="提交">		</p>	</form></body></html>