在JSF中使用foreach循环

Question

I need to create a list of commandbuttons on my page, but I have some trouble with it. 我需要在我的页面上创建一个命令按钮列表，但是我遇到了一些问题。 I pass the list from my bean through request.setAttribute and it seems to work when I get the values one at a time, but when I run through a foreach loop, they all seem to be null (And thereby being generated, and having a default value 0, "" etc., as far as I know). 我通过request.setAttribute从我的bean传递列表，它似乎在我一次获取一个值时工作，但是当我运行foreach循环时，它们似乎都是null（从而生成，并且具有默认值0，“”等，据我所知）。 Any help would be greatly appreciated! 任何帮助将不胜感激！ In the added code, I get the correct values when i make the buttons outside of the foreach loop, but not when I run the loop itself. 在添加的代码中，当我在foreach循环之外创建按钮时，我得到正确的值，但是当我运行循环本身时却没有。 The List is of integer type, and should later be a java object (ran into same problem). List是整数类型，稍后应该是一个java对象（遇到同样的问题）。 using JSF version 2.2. 使用JSF 2.2版。 Both logtest() and gotoprofile() prints the interestpointer out. logtest（）和gotoprofile（）都打印出兴趣指针。

my bean has: 我的豆子有：

@ManagedBean(name="MyProfile")
@RequestScoped

And I set my variable myInterestList in my bean with: 我在我的bean中设置我的变量myInterestList：

HttpSession session = (HttpSession) FacesContext.getCurrentInstance().getExternalContext().getSession(true);         
session.setAttribute("myInterestProfileName", profileName);


<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql"%>
<%@ page import="java.util.List,com.jsflogin.stringWithPointer" %>

<%@taglib prefix="h" uri="http://java.sun.com/jsf/html"%>
<%@ taglib prefix="f" uri="http://java.sun.com/jsf/core" %>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

<html>
 <f:view>



<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSF Successfull login</title>
</head>
<body>


    <h:form id="forloop">
            <c:set var ="myTempList" value="${myInterestListYay}" scope="session"/>
            <c:out value="interest list"/><p>
            <h:commandButton value="#{myInterestListYay[1]}" action="#{MyProfile.logTest}">
                 <f:setPropertyActionListener target ="#{MyProfile.interestPointer}" value = "#{myInterestListYay[1]}"/>
            </h:commandButton><p>


            <ui:repeat var="orly"value="${myInterestListYay}" varstatus="status"> 
                 <c:out value="${status.index}"/><h:commandButton value="#{orly}" action="#{MyProfile.logTest}">
                 <f:setPropertyActionListener target ="#{MyProfile.interestPointer}" value = "#{orly}"/>
            </h:commandButton><p>
           </ui:repeat>
           <c:forEach var="orly" items="${MyProfile.interestsAndPointers}"  varStatus="status" >
                 <c:out value="${status.index}"/><c:out value=": "/><c:out value="${orly.stringName}"/><h:commandButton value="go to interest page" action="#{MyProfile.goToInterestProfile}">
                 <f:setPropertyActionListener target ="#{MyProfile.interestPointer}" value = "#{orly.pointer}"/>
            </h:commandButton><p>
            </c:forEach>     
        </h:form>



    </body>
   </f:view> 
</html>

Answer 1

If you are using JSF 2 you should change your page to xhtml, then you can use ui:repeat and get a lot more goodies from facelets. 如果您使用的是JSF 2，则应将页面更改为xhtml，然后您可以使用ui：repeat并从facelets获得更多好处。

I made two very simple pages, one as JSP and the other one as XHTML. 我制作了两个非常简单的页面，一个用作JSP，另一个用作XHTML。 They use a managed bean in request scope. 他们在请求范围中使用托管bean。 Both are working and render three buttons in a row. 两者都在工作并连续渲染三个按钮。 Note that I use Glassfish as a server, since it was easier to getting started. 请注意，我使用Glassfish作为服务器，因为它更容易入门。 For the Tomcat(7.x) you might need to copy the jsf-api, jsf-impl (2.x) and jstl (1.2) libs into the classpath. 对于Tomcat（7.x），您可能需要将jsf-api，jsf-impl（2.x）和jstl（1.2）库复制到类路径中。

This is the JSP page: 这是JSP页面：

<%@page contentType="text/html" pageEncoding="UTF-8"%>

<%@taglib prefix="f" uri="http://java.sun.com/jsf/core"%>
<%@taglib prefix="h" uri="http://java.sun.com/jsf/html"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

<f:view>
  <html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
        <title>JSP Page</title>
    </head>
    <body>
        <h:form>
          <c:forEach var="item" items="#{cart.items}">
            <h:commandButton value="#{item}"/>
          </c:forEach>
        </h:form>
    </body>
  </html>
</f:view>

Here the XHTML Page: 这里是XHTML页面：

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
  xmlns:h="http://xmlns.jcp.org/jsf/html"
  xmlns:ui="http://java.sun.com/jsf/facelets">
  <h:head>
    <title>Simple JSF</title>
  </h:head>
  <h:body>
    <h:form>
        <ui:repeat value="#{cart.items}" var="item">
            <h:commandButton value="#{item}" />
        </ui:repeat>   
    </h:form>
  </h:body>
</html>

Why do you use a bean in request scope and set you variable there in the session? 为什么在请求范围中使用bean并在会话中设置变量？ Keep it simple and change the bean to session scope: 保持简单并将bean更改为会话范围：

@ManagedBean(name = "cart")
@SessionScoped
public class CartBean {

  private List<String> items;

  public CartBean() {
    items = new ArrayList<>();
    items.add("shirt");
    items.add("skirt");
    items.add("trouser");
  }

  public List<String> getItems() {
    return items;
  }

}

在JSF中使用foreach循环

问题描述

1 个解决方案

解决方案1
32 已采纳 2013-12-09 10:51:55

在JSF中使用foreach循环

问题描述

1 个解决方案

解决方案1 32 已采纳 2013-12-09 10:51:55

解决方案1
32 已采纳 2013-12-09 10:51:55