使用session和jsp实现简单购物车
程序员文章站
2022-03-01 18:43:02
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这里没有连接数据库，用的一个类模仿数据库了
（一）、实体类代码Book.java
public class Book implements Serializable{
private String id;
private String name;
private String price;
private String author;
public Book() {
super();
}
public Book(String id, String name, String price, String author) {
this.id = id;
this.name = name;
this.price = price;
this.author = author;
}
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;
}
public String getPrice() {
return price;
}
public void setPrice(String price) {
this.price = price;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
//重写hashCode和equals方法，怎样比较是否是同一个对象
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((id == null) ? 0 : id.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Book other = (Book) obj;
if (id == null) {
if (other.id != null)
return false;
} else if (!id.equals(other.id))
return false;
return true;
}
}
（二）、模仿数据库BookStore.java
public class BookStore {
static List<Book> booklist;
static {
booklist=new ArrayList<>();
booklist.add(new Book("1", "红楼梦", "78", "曹雪芹"));
booklist.add(new Book("2", "水浒传", "78", "施耐庵"));
booklist.add(new Book("3", "三国演义", "78", "罗贯中"));
booklist.add(new Book("4", "西游记", "78", "吴晨恩"));
}
public static List<Book> getBooklist() {
return booklist;
}
public static Book getBookById(String id) {
Book book=new Book();
book.setId(id);
int index=booklist.indexOf(book);
return booklist.get(index);
}
}
（三）、前端页面展示book.jsp
<body>
<table border="1px">
<caption>书籍列表</caption>
<%
List<Book> books=new BookStore().getBooklist();
for(Book book:books){
%>
<tr>
<td><%=book.getName() %></td>
<td><%=book.getPrice() %></td>
<td><%=book.getAuthor() %></td>
<td><a href="BookServlet?id=<%=book.getId()%>">添加商品到购物车</a></td>
</tr>
<%
}
%>
</table>
<hr>
<a href="show.jsp">查看购物车商品</a>
</body>
（四）、后台实现BookServlet
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html);charset=utf-8");
//1、获取传过来的商品ID
String id=request.getParameter("id");
//2、把对应商品放入购物车
Map<Book, Integer> cart=(Map<Book, Integer>)request.getSession().getAttribute("cart");
if(cart==null) {
cart=new HashMap<Book, Integer>();
}
//获取指定id的书籍对象
Book book=BookStore.getBookById(id);
//获取图书在购物车里面对应的数量
Integer count = cart.get(book);
if (count==null) {
count=1; //如果购物车里面没有改图书，数量=1
}else {
count+=1; //如果购物车里面有该图书，数量+1
}
//把购物车里面对应的图书数量进行更新
cart.put(book, count);
//更新session里面的map集合
request.getSession().setAttribute("cart", cart);
response.getWriter().write("<a href='book.jsp'>继续购物</a> <a href='show.jsp'>查看购物车</a>");
}
五、查看购物车前端实现show.jsp
<body>
<table border="1px">
<caption>购物车详情</caption>
<tr>
<td>书名</td>
<td>价格</td>
<td>作者</td>
<td>数量</td>
</tr>
<%
Map<Book, Integer> cart=(Map<Book, Integer>)request.getSession().getAttribute("cart");
if(cart!=null && cart.size()!=0){
Set<Book> books=cart.keySet();
for(Book book:books){
%>
<tr>
<td><%=book.getName() %></td>
<td><%=book.getPrice() %></td>
<td><%=book.getAuthor() %></td>
<td><%=cart.get(book) %></td>
</tr>
<%
}
}
%>
</table >
</body>