Spring MVC应用程序将库存添加到购物车jsp JAVA

我正在尝试使用可添加到购物车的某些库存编写简单的Web应用程序。我将复制代码和jsp文件。我希望我能够解决这个问题。我从数据库中获取数据。现在我想显示什么是添加到购物车，然后我会尝试将它保存在分贝。Spring MVC应用程序将库存添加到购物车jsp JAVA

全堆栈跟踪。

org.apache.jasper.JasperException: An exception occurred processing JSP page /WEB-INF/views/cart.jsp at line 14 

11:  <div style="padding-right: 40px"> 
12:   <table border="1"> 
13:    <tr> 
14:     <c:forEach items="${cpu}" var="c"> 
15:      <td>Name</td> 
16:      <td>${c.name}</td> 
17:     </c:forEach> 


Stacktrace: 
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:574) 
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:461) 
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396) 
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168) 
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303) 
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1243) 
    org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:968) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:870) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648) 
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:844) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108) 
root cause 

javax.servlet.ServletException: javax.servlet.jsp.JspTagException: Don't know how to iterate over supplied "items" in &lt;forEach&gt; 
    org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:909) 
    org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:838) 
    org.apache.jsp.WEB_002dINF.views.cart_jsp._jspService(cart_jsp.java:156) 
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438) 
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396) 
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168) 
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303) 
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1243) 
    org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:968) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:870) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648) 
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:844) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108) 
root cause 

javax.servlet.jsp.JspTagException: Don't know how to iterate over supplied "items" in &lt;forEach&gt; 
    org.apache.taglibs.standard.tag.common.core.ForEachSupport.toForEachIterator(ForEachSupport.java:274) 
    org.apache.taglibs.standard.tag.common.core.ForEachSupport.supportedTypeForEachIterator(ForEachSupport.java:238) 
    org.apache.taglibs.standard.tag.common.core.ForEachSupport.prepare(ForEachSupport.java:155) 
    javax.servlet.jsp.jstl.core.LoopTagSupport.doStartTag(LoopTagSupport.java:256) 
    org.apache.jsp.WEB_002dINF.views.cart_jsp._jspx_meth_c_005fforEach_005f0(cart_jsp.java:178) 
    org.apache.jsp.WEB_002dINF.views.cart_jsp._jspService(cart_jsp.java:138) 
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:438) 
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396) 
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:168) 
    org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:303) 
    org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1243) 
    org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1027) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:971) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:968) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:870) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:648) 
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:844) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:729) 
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) 
    org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:108)

cart.jsp

<body> 
    <div style="padding-right: 40px"> 
     <table border="1"> 
      <tr> 
       <c:forEach items="${cpu}" var="c"> 
        <td>Name</td> 
        <td>${c.name}</td> 
       </c:forEach> 



    </div>

控制器 @Controller

public class CartController { 

    @RequestMapping(value = "/cart", method = RequestMethod.POST) 
    public String someAction(@ModelAttribute("cpu") Cpu cpu, Model model) { 
     model.addAttribute("cpu", cpu); 
     return "cart"; 
    } 
}

的Cpu

@SuppressWarnings("serial") 
public class Cpu implements Serializable { 

    public static final String SESSION_PROPERTY = "cpu"; 

    private int id; 

    private String name; 

    private String socket; 

    private int price; 

    public int getId() { 
     return id; 
    } 

    public void setId(int id) { 
     this.id = id; 
    } 

    public String getName() { 
     return name; 
    } 

    public void setName(String name) { 
     this.name = name; 
    } 

    public String getSocket() { 
     return socket; 
    } 

    public void setSocket(String socket) { 
     this.socket = socket; 
    } 

    public int getPrice() { 
     return price; 
    } 

    public void setPrice(int price) { 
     this.price = price; 
    } 

}

来源

2016-04-25 RockOrDead

您可以从“不知道如何遍历提供的项目”到您的'Cpu'类型（显然不会实现'Iterable'）一路跟踪错误。不可能知道，因为这是您决定*不*包含的唯一代码。 – kryger

@kryger我已经添加了cpu类。 – RockOrDead

你试图使用<c:forEach>在您的自定义Cpu类型的单个实例进行迭代，而迭代明显的要求是...有，你可以遍历对象的集合。这就是JSTL规范说：

大量的集合类型由<c:forEach>支持，包括java.util.Collection中的所有实现（包括表，链表，ArrayList中，向量，堆栈，集），和java.util.Map（包括HashMap，Hashtable，Properties，Provider，Attributes）。

（...）

java.util.Iterator中和的java.util.Enumeration的实现都支持，以及（...）。

您的控制器应更改为创建List<Cpu>，稍后将通过模型属性传递给JSP页面。在网上商店中实施购物车的常见习惯用法是使用HttpSession来累积所有用户的物品。稍后，您可以访问CartController中的此共享会话对象，并检索用户放置的所有项目。

来源

2016-04-25 21:02:11 kryger

你能告诉我如何做到这一点？ – RockOrDead

你一周前已经在处理这个问题：http://stackoverflow.com/q/36682201/1240557。如果有一些基本概念你不明白，你应该从一个有信誉的来源参考正式文件或教程，而不是“尝试一切，直到它工作”。 – kryger

Spring MVC应用程序将库存添加到购物车jsp JAVA

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