>我收到以下错误，如附图所示：
Request method 'POST' not supported.
https://i.stack.imgur.com/SMRph.png
在购物车控制器中.java ：
/*
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* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.leapfrog.shoppingcart.controller;
import com.leapfrog.shoppingcart.entity.Cart;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpSession;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseStatus;
/**
*
* @author AshwinKArki
*/
@Controller
@RequestMapping(value="/sp")
public class ShoppingCartController {
@RequestMapping(value="/form",method=RequestMethod.GET)
public String index(ModelMap map){
map.put("cart",new Cart());
return "form";
}
@RequestMapping(value="/addcart",method=RequestMethod.POST)
public String addcart(@ModelAttribute("cart") Cart c,HttpSession session){
List<Cart> lst=(List<Cart>)session.getAttribute("cart");
if(lst==null){
lst=new ArrayList<>();
lst.add(c);
}
else{
boolean flag=false;
for(Cart cart:lst){
if(cart.getId()==c.getId()){
cart.setQuantity(cart.getQuantity()+1);
flag=true;
break;
}
}
if(flag==false) {
lst.add(c);
}
}
session.setAttribute("cart", lst);
session.setAttribute("total",getTotal(lst));
return "cart";
}
public float getTotal(List<Cart> lst){
float total=0;
for(Cart cart:lst){
total+=(cart.getQuantity()*cart.getPrice());
}
return total;
}
}
在形式上.jsp ：
<%--
Document : form
Created on : 23-Jan-2017, 12:16:53
Author : AshwinKArki
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://www.springframework.org/tags/form" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<c:form modelAttribute="cart" action="" method="POST">
ID:<c:input path="id" /> <br/>
Name:<c:input path="name" /> <br/>
Price:<c:input path="price" /> <br/>
Quantity:<c:input path="quantity" /> <br/>
<input type="submit" value="Add to CART" />
</c:form>
</body>
</html>
In CART.jsp
<%--
Document : cart
Created on : 23-Jan-2017, 12:35:07
Author : AshwinKArki
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>
<h1>Your cart</h1>
<table border="1px">
<c:forEach var="ce" items="<%= request.getSession().getAttribute("cart")%>" >
<tr>
<td>${ce.id}</td>
<td>${ce.name}</td>
<td>${ce.price}</td>
<td>${ce.quantity}</td>
<td>
Remove
</td>
</tr>
<tr>
<td>
TOTAL: <%= request.getSession().getAttribute("total") %>
</td>
</tr>
</c:forEach>
</table>
</body>
</html>
**`strong text`**]
您的动作标签在 <c:form> 中为空，因此它在当前 URL 中发出 POST 请求，即"sp/form"。尝试将其设置为"addcart"或"sp/addcart"。