Java web：含个人详细总结，EL表达式param,JSP，servlet作业【诗书画唱】
实现珠宝店购物车功能：
package com.Servlet;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Servlet implementation class CartServlet
*/
@WebServlet("/CartServlet")
public class CartServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public CartServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request,
* HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws
ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest
* request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
//获取商品名称和价格：
String name = request.getParameter("name");
name = new String(name.getBytes("iso8859-1"),"utf-8");
String strPrice = request.getParameter("price");
//将strPrice转换成数字：
Double price = 0.0;
if(strPrice != null && strPrice.length() > 0) {
price = Double.parseDouble(strPrice);
}
// System.out.println(name);
// System.out.println(strPrice);
//封装数据：
Product p = new Product();
p.setName(name);
p.setPrice(price);
//获取session对象：
HttpSession session = request.getSession();
//尝试着从session中获取购物车对象（_cart）：
Object objCart = session.getAttribute("_cart");
//什么样的情况下就是第一次添加购物车：
if(objCart == null) {
//如果是第一次添加购物车，就必须new出这个购物车
//个人的总结：因为session.getAttribute("_cart")获取自要用
// session.setAttribute("_cart", cart);发送到的
// cartShow.jsp文件。：
Map<String,Integer>cart = new HashMap<String,Integer>();
cart.put(name, 1);
System.out.println(cart);
//将cart放到session中去：
session.setAttribute("_cart", cart);
} else {
//如果是第n次添加购物车，将objCat转换成Map：
Map<String,Integer>cart = (HashMap<String,Integer>)objCart;
//判断选中的商品在map中是否已经存在：
//contain：包含【英[kənˈteɪnz] 】
if(cart.containsKey(name)){//如果选中的商品已经存在
//数量加1：
Integer count = cart.get(name);
count ++;
//将加1以后的数量放回map中
cart.put(name, count);
} else {
cart.put(name, 1);
}
System.out.println(cart);
//将cart放回session中：
session.setAttribute("_cart", cart);
}
//跳转回shopping.jsp：
request.getRequestDispatcher("shoppingStart.jsp")
.forward(request, response);
}
}
package com.Servlet;
public class Product {
private Integer id;
private String name;
private Double price;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Double getPrice() {
return price;
}
public void setPrice(Double price) {
this.price = price;
}
}
package com.Servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class shoppingServ
*/
@WebServlet("/shoppingServlet")
public class shoppingServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public shoppingServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
this.doPost(request, response);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
//商品名称：
String name = request.getParameter("name");
//中文乱码处理：
name = new String(name.getBytes("iso8859-1"),"utf-8");
// String strPrice = request.getParameter("price");
// //商品价格
// Double price = 0.0;
// //如果strPrice不为空，就转换成Double类型
// if(strPrice != null && strPrice.length() > 0) {
// price = Double.parseDouble(strPrice);
// }
// //商品图片路径：
// String src = request.getParameter("src");
request.setCharacterEncoding("gbk");
request.getRequestDispatcher("detailShow.jsp?name=" + name)
.forward(request, response);
}
}
<%@page import="java.util.Iterator"%>
<%@page import="java.util.Set"%>
<%@page import="java.util.HashMap"%>
<%@page import="java.util.Map"%>
<%@ page language="java" contentType="text/html;
charset=UTF-8" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()
+"://"+request.getServerName()
+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base hreff="<%=basePath%>">
<title></title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<style type="text/css">
* {
font-size:50px;
}
</style>
</head>
<body>
<h1>购物车列表</h1>
<ul>
<%--自己的总结：
当点击“添加商品按钮后”，触发方法addCart，通过
“addCart('${param.name}',${param.price})”
传值给CartServlet.java文件中。
在CartServlet.java文件中用
request.getParameter("name")等获取。
用session.setAttribute("_cart", cart);
将cart放回session中。 --%>
<%
// 因为在CartServlet.java
// 文件中有session.setAttribute("_cart", cart);
/// 所以可以用 session.getAttribute("_cart");获取购物车cart：
Object objCart = session.getAttribute("_cart");
Map<String,Integer>cart = new HashMap<String,Integer>();
if(objCart != null) {
cart = (HashMap<String,Integer>)objCart;
}
Set<String>keys = cart.keySet();
//下面是用迭代器遍历添加到购物车中的内容：
Iterator<String> it = keys.iterator();
while(it.hasNext()) {
//商品名称：
String name = it.next();
//商品数量：
Integer count = cart.get(name);
%>
<li><%=name %>:<%=count %></li>
<%
}
%>
</ul>
<a hreff="shoppingStart.jsp">返回</a>
</body>
</html>
<%@ page language="java" contentType="text/html;
charset=UTF-8" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()
+"://"+request.getServerName()
+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base hreff="<%=basePath%>">
<title></title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<script type="text/javascript">
//添加到购物车功能
function addCart(name,price){
window.location.hreff = 'CartServlet?name=' + name
+ '&price=' + price;
}
</script>
</head>
<body>
<h1>显示珠宝详情</h1>
<%--
个人的总结：
如果用“?XXX=YYY”等的格式地址栏等传参，
那么可以用${param.XXX }获取YYY的值
--%>
<h1>商品名称：${param.name }</h1>
<h1><img src="${param.src }" /></h1>
<h1>￥${param.price }</h1>
<input id="btn" type="button" value="加入购物车"
onclick="addCart('${param.name}',${param.price});" />
</body>
</html>
<%@ page language="java" contentType="text/html;
charset=UTF-8" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()
+"://"+request.getServerName()
+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base hreff="<%=basePath%>">
<title></title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<style type="text/css">
* {
font-size:52px;
}
</style>
<%-- 个人的总结：
如果路径名为XXX格式，那么XXX是servlet文件中
用@WebServlet("/shoppingServlet")声明的路径;
如果路径名为XXX.jsp格式，那么XXX是jsp文件
的路径，在同级目录下相对路径为“文件名+后缀”;
--%>
<script type="text/javascript">
function detail(name,price,src){
window.location.hreff = 'shoppingServlet?name=' + name
+ '&price=' + price + '&src=' + src;
}
function viewCart(){
window.location.hreff= 'cartShow.jsp';
}
</script>
</head>
<body>
<table border="1" align="center">
<tr>
<th>珠宝名称</th>
<th>珠宝图片</th>
<th>珠宝价格</th>
<th><a hreff="javascript:viewCart();">查看购物车</a></th>
</tr>
<tr>
<td>橙宝石</td>
<td><img src="img/14.png" /></td>
<td>￥200000</td>
<td><a hreff="javascript:detail
('橙宝石',200000,'img/14.png');">查看详情</a></td>
</tr>
<tr>
<td>紫晶</td>
<td><img src="img/16.png" /></td>
<td>￥300000</td>
<td><a hreff="javascript:detail
('紫晶',300000,'img/16.png');">查看详情</a></td>
</tr>
<tr>
<td>红宝石</td>
<td><img src="img/41.png" /></td>
<td>￥500000</td>
<td><a hreff="javascript:
detail('红宝石',500000,'img/41.png');">查看详情</a></td>
</tr>
<tr>
<td>紫宝石</td>
<td><img src="img/5.png" /></td>
<td>￥100000</td>
<td><a hreff="javascript:
detail('紫宝石',100000,'img/5.png');">查看详情</a></td>
</tr>
</table>
</body>
</html>
