Session案例：简易的购物车

三个jsp和两个Servlet组成：在WebContent下边建立一个shoppingcart文件夹，将三个jsp文件放在里面：

1.建立一个step1.jsp文件，出现一个表格，是一个复选框，可以选择要购买的书籍，完毕后，点击Submit,跳转到Servlet类 ProcessStep1Servlet里面

<%@ 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/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <h2>step1: 选择要购买的书籍！</h2>
    
    <form action="<%= request.getContextPath() %>/processStep1Servlet" method="post">
    
        <table border="1" cellpadding="10" cellspacing="0">
            <tr>
                <th>书名</th>  
                <th>点击购买</th>
            </tr>    
            
            <tr>
                <td>Oracle</td>  
                <td><input type="checkbox" name="book" value="Oracle"/></td>
            </tr>
            
            <tr>
                <td>java</td>  
                <td><input type="checkbox" name="book" value="java"/></td>
            </tr>
            
            <tr>
                <td>C++</td>  
                <td><input type="checkbox" name="book" value="C++"/></td>
            </tr>
            
            <tr>
                <td>mysql</td>  
                <td><input type="checkbox" name="book" value="mysql"/></td>
            </tr>
            
            <tr>
                <td>WEB</td>  
                <td><input type="checkbox" name="book" value="WEB"/></td>
            </tr>
            
            <tr>
                <td colspan="2"> <input type="submit" value="Submit"/></td>
            </tr>
            
        </table>
    
    </form>
</body>
</html>

2.建立一个Servlet类 ProcessStep1Servlet，里面有doPost方法，可实现session方法（好处就是获取用户选择书名的id,保存到后边再使用），获取用户选择的书名，使绝对路径的方法重定向到step1.jsp页面； response.sendRedirect(request.getContextPath()+"/shoppingcart/step2.jsp");

public class ProcessStep1Servlet extends HttpServlet {

private static final long serialVersionUID = 1L;

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
　　//1. 获取选中的图书的信息
　　String [] books = request.getParameterValues("book");
　　//2. 把图书信息放入到 HttpSession 中
　　request.getSession().setAttribute("books", books);

　　//2. 重定向页面到 shoppingcart/step-2.jsp
　　System.out.println(request.getContextPath() + "/shoppingcart/step-2.jsp");
　　response.sendRedirect(request.getContextPath() + "/shoppingcart/step-2.jsp");
　　}

}

3.在step2.jsp页面，是用户输入个人信息页面，付款，发送货物需要的信息，然后跳转到Servlet类 processStep2Servlet 对用户的信息封装到customer类里面

<%@ 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/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <h2>step2: 请输入寄送地址和信用卡</h2>
    
    <form action="<%= request.getContextPath() %>/processStep2Servlet" method="post">
        <table border="1" cellpadding="10" cellspacing="0">
            <tr>
                <td colspan="2">寄送信息：</td>
            </tr>
            
            <tr>
                <td>姓名：</td>
                <td><input type="text" name="name"/></td>
            </tr>
            
            <tr>
                <td>地址：</td>
                <td><input type="text" name="address"/></td>
            </tr>
            
            <tr>
                <td>联系电话：</td>
                <td><input type="text" name="phone"/></td>
            </tr>
        
            <tr >
                <td colspan="2">信用卡信息：</td>
            </tr>
            
            <tr>
                <td>信用卡种类</td>
                <td>
                    <input type="radio" name="cardType" value="nong"/>nong
                    <input type="radio" name="cardType" value="gong"/>gong
                </td>
                
            </tr>
            
            <tr>
                <td>信用卡号：</td>
                <td><input type="text" name="card"/></td>
            </tr>
            
            <tr>
                <td colspan="2"> <input type="submit" value="Submit"/></td>
            </tr>
        </table>
    
    </form>
</body>
</html>

4.建立一个Servlet类，里面有doPost方法，对用户的信息封装到customer类里面，session实例，保存用户的id信息，便于后边输出，然后重定向到confirm.jsp页面，跳转一面使用了绝对路径：response.sendRedirect(request.getContextPath()+"/shoppingcart/confirm.jsp");

public class ProcessStep2Servlet extends HttpServlet {

private static final long serialVersionUID = 1L;

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

　　//1. 获取请求参数: name, address, cardType, card
　　String name = request.getParameter("name");
　　String address = request.getParameter("address");
　　String cardType = request.getParameter("cardType");
　　String card = request.getParameter("card");

　　Customer customer = new Customer(name, address, cardType, card);

　　//2. 把请求信息存入到 HttpSession 中

　　HttpSession session = request.getSession();
　　session.setAttribute("customer", customer);

　　//3. 重定向页面到 confirm.jsp
　　response.sendRedirect(request.getContextPath() + "/shoppingcart/confirm.jsp");
　　}

}

5.confirm.jsp页面，使用了session实例，将前边的用户选择的书籍和用户输入的个人信息，输出到这个页面

<%@page import="com.lanqiao.javatest.Customer"%>
<%@ 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/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <%
        Customer customer=(Customer)session.getAttribute("customer");
        String [] books=(String [])session.getAttribute("books");
    %>
     
     <h2>信息表单</h2>
    <table>
        <tr>
            <td>顾客姓名：</td>
            <td><%=customer.getName() %></td>
        </tr>
        
        <tr>
            <td>顾客地址：</td>
            <td><%=customer.getAddress() %></td>
        </tr>
        
        <tr>
            <td>顾客联系电话：</td>
            <td><%=customer.getPhone() %></td>
        </tr>
        
        <tr>
            <td>顾客卡类型：</td>
            <td><%=customer.getCardType() %></td>
        </tr>
        
        <tr>
            <td>顾客的卡号：</td>
            <td><%=customer.getCard() %></td>
        </tr>
        
        <tr>
            <td>您购买的书：</td>
            <td>
                <%
                    for(String book:books){
                        out.print(book);
                        out.print("		");
                    }
                %>
            </td>
        
        </tr>
    
    </table>
</body>
</html>

6.lib下边的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">
  <servlet>
    <description></description>
    <display-name>ProcessStep1Servlet</display-name>
    <servlet-name>ProcessStep1Servlet</servlet-name>
    <servlet-class>com.lanqiao.javatest.ProcessStep1Servlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ProcessStep1Servlet</servlet-name>
    <url-pattern>/processStep1Servlet</url-pattern>
  </servlet-mapping>
  <servlet>
    <description></description>
    <display-name>ProcessStep2Servlet</display-name>
    <servlet-name>ProcessStep2Servlet</servlet-name>
    <servlet-class>com.lanqiao.javatest.ProcessStep2Servlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ProcessStep2Servlet</servlet-name>
    <url-pattern>/processStep2Servlet</url-pattern>
  </servlet-mapping>
</web-app>

7.Customer封装类：

package com.lanqiao.javatest;

public class Customer {
    private String name;
    private String address;
    private String phone;
    private String cardType;
    private String card;
    
    public Customer() {
        super();
    }

    public Customer(String name, String address, String phone, String cardType, String card) {
        super();
        this.name = name;
        this.address = address;
        this.phone = phone;
        this.cardType = cardType;
        this.card = card;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getCardType() {
        return cardType;
    }

    public void setCardType(String cardType) {
        this.cardType = cardType;
    }

    public String getCard() {
        return card;
    }

    public void setCard(String card) {
        this.card = card;
    }

    @Override
    public String toString() {
        return "Customer [name=" + name + ", address=" + address + ", phone=" + phone + ", cardType=" + cardType
                + ", card=" + card + "]";
    }
    
    
}

相关阅读:
jquery toggle(listenerOdd, listenerEven)
struts quick start
hdu 1518 Square (dfs)
hdu 2544 最短路 (最短路径)
hdu 1754 I Hate It (线段树)
hdu 1856 More is better (并查集)
hdu 1358 Period (KMP)
hdu 2616 Kill the monster (DFS）
hdu 2579 Dating with girls(2) (bfs)
zoj 2110 Tempter of the Bone (dfs)
原文地址：https://www.cnblogs.com/lxnlxn/p/5823892.html