春節作業-小練習-購物車
showServlet.java
package com.kd.servlet;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
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 com.kd.entity.Goods;
import com.kd.service.GoodsService;
import com.kd.service.GoodsServiceImpl;
@WebServlet("/showServlet")
public class showServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
GoodsService goodsService=new GoodsServiceImpl();
int pageNum=1;
int pageSize=3;
if(request.getParameter("pageNum")!=null) {
pageNum=Integer.parseInt(request.getParameter("pageNum"));
}
try {
List<Goods> list=goodsService.getPaged(pageNum, pageSize);
request.setAttribute("list", list);
int count = goodsService.getCount();
int num=count%pageSize ==0 ? count/pageSize : count/pageSize+1;
request.setAttribute("num", num);
request.setAttribute("currNum", pageNum);
request.getRequestDispatcher("/WEB-INF/jsp/showGoods.jsp").forward(request, response);
} catch (Exception e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
showGoods.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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>
<form>
<div style="text-align:center">
<h1>商品信息瀏覽</h1>
</div>
<table border="1" width="800" style="width: 80%;margin:auto">
<tr>
<th>編號</th>
<th>名稱</th>
<th>價格</th>
<th>出廠日期</th>
<th>生產廠家</th>
<th>描述</th>
<th>操作</th>
</tr>
<c:forEach items="${list}" var="goods">
<tr>
<td><input type="text" value="${goods.id}" readonly="readonly"></td>
<td>${goods.name}</td>
<td>${goods.price}</td>
<td>${goods.date}</td>
<td>${goods.company}</td>
<td>${goods.desc}</td>
<td><a href="${pageContext.request.contextPath}/shoppingServlet?id=${goods.id}">點擊購買</a></td>
</tr>
</c:forEach>
<tr>
<td colspan="7">
<a href="${pageContext.request.contextPath}/showServlet?pageNum=1">首頁</a>
<c:if test="${currNum==1}">
<a>上一頁</a>
</c:if>
<c:if test="${currNum>1}">
<a href="${pageContext.request.contextPath}/showServlet?pageNum=${currNum-1}">上一頁</a>
</c:if>
<c:forEach begin="1" end="${num}" var="pageNum">
<a href="${pageContext.request.contextPath}/showServlet?pageNum=${pageNum}">${pageNum}</a>
</c:forEach>
<c:if test="${currNum==num}">
<a>下一頁</a>
</c:if>
<c:if test="${currNum<num}">
<a href="${pageContext.request.contextPath}/showServlet?pageNum=${currNum+1}">下一頁</a>
</c:if>
<a href="${pageContext.request.contextPath}/showServlet?pageNum=${num}">最後一頁</a>
第<input type="text" size="1" id="no">頁<input type="button" onclick="go()" value="go">
</td>
</tr>
</table>
</form>
</body>
<script>
function go(){
var no=document.getElementById("no").value;
if(no==""){
alert("請輸入頁號!");
return;
}
if(parseInt(no)>${num}||parseInt(no)<1){
alert("頁號不存在!");
return;
}
location.href="${pageContext.request.contextPath}/showServlet?pageNum="+no;
}
</script>
</html>
shoppinServlet.java
package com.kd.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 com.kd.entity.Goods;
import com.kd.service.GoodsService;
import com.kd.service.GoodsServiceImpl;
@WebServlet("/shoppingServlet")
public class shoppingServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String id=request.getParameter("id");
GoodsService goodsService=new GoodsServiceImpl();
try {
Goods goods=goodsService.getById(id);
Map<Goods,Integer> map =(Map<Goods,Integer>)request.getSession().getAttribute("map");
//判斷map是否爲空
if(map == null) {//第一次購物
//創建購物車
map =new HashMap<Goods,Integer>();
//把商品名稱和數量放入到map中（購物車中）
map.put(goods, 1);
} else { //不是第一次購物
//判斷是否有相同名稱session
//第一種方式可以遍歷
if(map.containsKey(goods)) {//有相同名稱的key
//得到商品的數量，+1
int num = map.get(goods);
//把num+1，放到購物車
map.put(goods, num+1);
} else { //沒有相同的key
//直接把商品名和數量1添加到購物車
map.put(goods, 1);
}
}
int count=0;
for ( Goods good : map.keySet()) {
count+=map.get(good)*good.getPrice();
}
request.setAttribute("count",count);
request.getSession().setAttribute("map", map);
request.getRequestDispatcher("/WEB-INF/jsp/shopping.jsp").forward(request, response);
} catch (Exception e) {
e.printStackTrace();
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
shopping.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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>
<form action="${pageContext.request.contextPath}/shoppingServlet" method="post">
<div style="text-align:center">
<h1>我的購物車</h1>
</div>
<table border="1" width="800" style="width: 80%;margin:auto">
<tr>
<th>編號</th>
<th>名稱</th>
<th>價格</th>
<th>數量</th>
<th>小計</th>
</tr>
<c:forEach items="${map}" var="goods">
<tr>
<td>${goods.key.id}</td>
<td>${goods.key.name}</td>
<td>${goods.key.price}</td>
<td>${map.get(goods.key)}</td>
<td>${map.get(goods.key)*goods.key.price}</td>
</tr>
</c:forEach>
<tr>
<td colspan="5" style="vertical-align:middle; text-align:center;">總計:${count}</td>
</tr>
<tr>
<td colspan="5"><a href="${pageContext.request.contextPath}/showServlet">返回商品信息界面</a></td>
</tr>
</table>
</form>
</body>
</html>
