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会话管理技术实战(购物车案例)

案例技术管理实战会话购物车

2023-06-13 09:15:16 时间

会话管理技术实战(购物车案例)

 **[1].创建Book封装图书信息:Book
 [2].创建BookDB,模拟数据库，里面是保存图书
 [3].提供图书的购买页面:ListBookServlet
 [4].添加购物车功能:PurcharseServlet
 [5].回显购物车图书信息:CartServlet**

如果浏览器禁用了cookie，咱们的购物车功能就不能实现了，因为session是基于cookie实现的。 解决方案：提示用户开启cookie

1.Book.java（封装图书信息）

package cn.itcast.chapter05.session.example01;

public class Book {
private String id;
private String name;
public Book() {
	
}
public Book(String id, String name) {
	this.id = id;
	this.name = name;
}
public String getId() {
	return id;
}
public void setId(String id) {
	this.id = id;
}
public String getName() {
	return name;
}
public void setName(String name) {
	this.name = name;
}
}

2.BookDB.java（模拟数据库功能）

package cn.itcast.chapter05.session.example01;

import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;

public class BookDB {
private static Map<String,Book> map=new LinkedHashMap<String,Book>();
static {
	map.put("1", new Book("1","javaWeb"));
	map.put("2", new Book("2","jdbc入门"));
	map.put("3", new Book("3","java基础"));
	map.put("4", new Book("4","struts框架"));
	map.put("5", new Book("5","hibernate框架"));
}
//1.得到所有图书
public static Collection<Book> getAll(){
	return map.values();
}
//2.根据map的key，也就是图书的id得到某本图书
public static Book getBook(String id) {
	return map.get(id);
}

}

3.ListBookServlet.java（图书购买页面）

package cn.itcast.chapter05.session.example01;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collection;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 提供一个购买图书的页面
 */
public class ListBookServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ListBookServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		//处理响应中文的乱码
		response.setContentType("text/html;charset=utf-8");
		//1.得到所有图书
		Collection<Book> books=BookDB.getAll();
		//2.回显页面
		PrintWriter out=response.getWriter();
		out.print("以下是本网站售卖的所有图书:"+"<br/><br/>");
		//3.遍历集合，把图书回显到页面
		for(Book b:books) {
			//4.得到图书名称
			String name=b.getName();
			String id=b.getId();
			//提供一个购买图书的链接
			String url="<a href='/chapter05/purcharse?id="+id+"'>点击购买</a>";
			out.print("图书名称:   "+name+"   "+url+"<br/><br/>");
		}	
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

4.添加购物车 PurcharseServlet

package cn.itcast.chapter05.session.example01;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 添加购物车功能
 */
public class PurcharseServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public PurcharseServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	     response.setContentType("text/html;charset=utf-8");
		//1.获取图书信息
		String id=request.getParameter("id");
		//判断id是否存在
		if(id==null) {//说明没有购买图书
			response.sendRedirect("/chapter05/list");//回到购买图书的页面
			return;
		}
		//2.图书已经购买了
		Book book=BookDB.getBook(id);
		//3.把图书添加到购物车
		HttpSession session=request.getSession();
		List<Book> list=(List<Book>) session.getAttribute("cart");
		//4.判断购物车是否存在:是不是首次购买图书
		if(list==null) {//首次购买book
			list=new ArrayList<Book>();
			session.setAttribute("cart", list);
		}
		//5.把图书添加到购物车
		list.add(book);
		//6.把请求跳转到CartServlet
		//session基于自己创建的cookie来完成效果,在浏览器关闭后，cookie对象还存在,就能找到session对象
		Cookie cookie=new Cookie("JESSIONID",session.getId());
		cookie.setMaxAge(60*60*24);
		cookie.setPath("/chapter05");
		response.addCookie(cookie);
		//跳转到CartServlet里面
		response.sendRedirect("/chapter05/cart");	
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
}

5.回显购物车图书信息: CartServlet.java

package cn.itcast.chapter05.session.example01;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * Servlet implementation class CartServlet
 */
public class CartServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	response.setContentType("text/html;charset=utf-8");
	PrintWriter out=response.getWriter();
	//1.得到购物车
	List<Book> cart=null;
	//2.得到用户自己的session
	HttpSession session=request.getSession(false);
	//3.自己定义一个flag,判断购物车里面是否有图书
	boolean cartFlag=true;
	if(session==null) {//购物车里没有图书
		cartFlag=false;
	}else {
		cart=(List<Book>) session.getAttribute("cart");
		if(cart==null) {
			cartFlag=false;
		}
	}
	//4.购物车里就有商品了
	if(!cartFlag) {//没有
		out.print("对不起，你的购物车里没有图书，请去购买");
	}else {
		//购物车有图书
		out.print("购买图书如下:"+"<br/>");
		for(Book b:cart) {
			out.print("购买的图书: "+b.getName()+"<br/>");
		}
	}
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}
}

实现: 1.启动服务器：访问http://localhost:8080/chapter05/list

2.随便点击购买基本图书这里我点击javaWeb 和jdbc入门（这里跳转到了CartServlet）

web.xml文件：

<?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_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>chapter05</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description></description>
    <display-name>LastAccessServlet</display-name>
    <servlet-name>LastAccessServlet</servlet-name>
    <servlet-class>cn.itcast.chapter05.cookie.example.LastAccessServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LastAccessServlet</servlet-name>
    <url-pattern>/last</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>ListBookServlet</display-name>
    <servlet-name>ListBookServlet</servlet-name>
    <servlet-class>cn.itcast.chapter05.session.example01.ListBookServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ListBookServlet</servlet-name>
    <url-pattern>/list</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>PurcharseServlet</display-name>
    <servlet-name>PurcharseServlet</servlet-name>
    <servlet-class>cn.itcast.chapter05.session.example01.PurcharseServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>PurcharseServlet</servlet-name>
    <url-pattern>/purcharse</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>CartServlet</display-name>
    <servlet-name>CartServlet</servlet-name>
    <servlet-class>cn.itcast.chapter05.session.example01.CartServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>CartServlet</servlet-name>
    <url-pattern>/cart</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>IndexServlet</display-name>
    <servlet-name>IndexServlet</servlet-name>
    <servlet-class>cn.itcast.chapter05.example02.IndexServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>IndexServlet</servlet-name>
    <url-pattern>/index</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>LoginServlet</display-name>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>cn.itcast.chapter05.example02.LoginServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>LogOutServlet</display-name>
    <servlet-name>LogOutServlet</servlet-name>
    <servlet-class>cn.itcast.chapter05.example02.LogOutServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LogOutServlet</servlet-name>
    <url-pattern>/logOut</url-pattern>
  </servlet-mapping>
</web-app>

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会话管理技术实战(购物车案例)

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