代码如下：
<html>
<head>
<title>
carts
</title>
</head>
<body bgcolor="white">
<form action="carts.jsp" meteod="post">
<font size="4" color="#CC0000">
Please enter item to add or remove
<br>
Add item:
<select name="item">
<option>A
<option>B
<option>C
</select>
<p><input type="submit" value="add">
<input type="submit" value="remove"></P>
</font>
</form>
</body>
</html>
<html>
<head>
<title>
carts
</title>
</head>
<body bgcolor="white">
<form action="carts.jsp" meteod="post">
<font size="4" color="#CC0000">
Please enter item to add or remove
<br>
Add item:
<select name="item">
<option>A
<option>B
<option>C
</select>
<p><input type="submit" value="add">
<input type="submit" value="remove"></P>
</font>
</form>
</body>
</html>
import javax.servlet.http.*;
import java.util.Enumeration;public class DummyCarts {
Vector v= new Vector();
String submit=null;
String item=null; private void addItem(String name){
if (name != null)
v.addElement(name);}private void removeItem(String name){
v.remove(name);}public void setItem(String name){
item=name;} public void setSubmit(String s){
submit=s;}
public String[]getItems(){
String[]s=new String[v.size()];
v.copyInto(s);
return s;
} public void processRequest(HttpServletRequest request){
if(submit==null)
addItem(item);
else if(submit.equals("add"))
addItem(item);
else if(submit.equals("remove"))
removeItem(item);
reset();
} private void reset(){
submit = null;
item=null;
}
}
<html>
<head>
<title>
carts
</title>
</head>
<jsp:useBean id="cart" scope="session" class="com.mycompany.bean.DummyCarts" />
<jsp:setProperty name="cart" property="*" />
<%
cart.processRequest(request);
%>
<font size=4 color="#CC000">
<br>You have the following items in your carts;
</font>
<o1>
<%
String[]items=cart.getItems();
for( int i=0; i<items.length;i++){
%>
<li>
<%=items[i]%>
<%}%>
</o1>
<hr>
<%@ include file="carts.html"%>
</html>