ViewScoped bean 在每个请求上构建...第 99 部分 [重复]

Question

啊...这似乎有一百个答案，我还没有找到适合我的答案，所以我想我真的会再问一次。这是我的场景：

从技术上讲，我的网站只有一个页面，其内容被换出，而不是您导航到的多个页面。起点是这个块：

<?xml version="1.0" encoding="UTF-8"?>
<f:view xmlns:f="http://java.sun.com/jsf/core"
  xmlns:h="http://java.sun.com/jsf/html"
  xmlns:ui="http://java.sun.com/jsf/facelets">
  <h:head />
  <h:body>
    <ui:include src="resourceInclude.xhtml" />
    <ui:include src="main.xhtml" />
  </h:body>
</f:view>

resourceInclude.xhtml 包含我的 css 文件：

<?xml version="1.0" encoding="UTF-8"?>
<ui:composition xmlns:h="http://java.sun.com/jsf/html"
  xmlns:ui="http://java.sun.com/jsf/facelets">
  <h:outputStylesheet library="css" name="test.css" target="head" />
</ui:composition>

而 main.xhtml 是视图：

<?xml version="1.0" encoding="UTF-8"?>
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
  xmlns:ui="http://java.sun.com/jsf/facelets"
  xmlns:h="http://java.sun.com/jsf/html">
  <h:panelGroup styleClass="test-container" layout="block">
    <h:form id="main-form">
      <h:panelGroup styleClass="test-header" layout="block">
        <h:panelGroup styleClass="navigation" layout="block">
          <ul>
            <li><h:commandLink action="#{viewSelector.setModeHome}">
                <h:outputText value="Home" />
              </h:commandLink></li>
            <li><h:commandLink action="#{viewSelector.setModeReports}">
                <h:outputText value="ASAP Reports" />
              </h:commandLink></li>
            <li><h:commandLink action="#{viewSelector.setModeSupport}">
                <h:outputText value="Technical Support" />
              </h:commandLink></li>
            <li><h:commandLink action="#{viewSelector.setModeHelp}">
                <h:outputText value="Help" />
              </h:commandLink></li>
          </ul>
        </h:panelGroup>
      </h:panelGroup>
      <h:panelGroup styleClass="test-content" layout="block">
        <ui:include src="#{viewSelector.modeName}-view.xhtml" />
      </h:panelGroup>
      <h:panelGroup styleClass="test-footer" layout="block">
        <h:messages />
      </h:panelGroup>
    </h:form>
  </h:panelGroup>
</ui:composition>

它由三个h:panelGroups 组成。第一个是一组四个通用导航链接，每个链接都会更改viewSelector.modeName 值，该值用于包含第二个h:panelGroup 中的内容，因此<ui:include src="#{viewSelector.modeName}-view.xhtml" />。我已经为这个例子去掉了这个，所以每个视图基本上都是这样的：

<?xml version="1.0" encoding="UTF-8"?>
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
  xmlns:ui="http://java.sun.com/jsf/facelets"
  xmlns:h="http://java.sun.com/jsf/html">
  <h:panelGroup styleClass="test-home-view">
    <p>home</p>
  </h:panelGroup>
</ui:composition>

第三个h:panelGroup 是所有消息的页脚，用于调试问题所在。

无论如何，每次我单击导航链接之一时，都会调用 viewSelector bean 的构造函数。这是我的 viewSelector bean 的样子：

package org.mitre.asias.aires.controller;


import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;


import org.apache.log4j.Logger;


@ManagedBean( name="viewSelector" )
@ViewScoped
public class ViewSelector {
    protected static Logger log = Logger.getLogger( ViewSelector.class );
    private Mode mode = Mode.HOME;
    public static final String PORTLET_NAME = "Test";

    public static enum Mode {
        HOME(1, "home"),
        REPORTS(2, "reports"),
        SUPPORT(3, "support"),
        HELP(4, "help");

        private int value;
        private String name;

        private Mode( int value, String name ) {
            this.value = value;
            this.name = name;
        }

        public int getValue() {
            return value;
        }

        public String getName() {
            return name;
        }
    }

    public ViewSelector() {
        log.trace( "constructing new ViewSelector" );
    }

    public Mode getMode() {
        log.trace( "getting mode" );

        return mode;
    }

    public String getModeName() {
        log.debug( "in getmodename" );
        return getMode().getName();
    }

    public String getPortletName() {
        return PORTLET_NAME;
    }

    public boolean isModeReports() {
        return getMode() == Mode.REPORTS;
    }

    public void setMode( Mode mode ) {
        this.mode = mode;
    }

    public void setModeHelp() {
        setMode( Mode.HELP );
    }

    public void setModeHome() {
        setMode( mode = Mode.HOME );
    }

    public void setModeReports() {
        setMode( mode = Mode.REPORTS );
    }

    public void setModeSupport() {
        setMode( mode = Mode.SUPPORT );
    }
}

我知道我一定是以错误的方式做某事，否则我错过了关于 JSF 如何工作的核心内容。任何输入？

Answer 1

<ui:include src> 中的 EL 导致了这种情况。

如果不能按照issue 1492 禁用web.xml 中的部分状态保存，则

<context-param>
    <param-name>javax.faces.PARTIAL_STATE_SAVING</param-name>
    <param-value>true</param-value>
</context-param>

那么你需要更换

<ui:include src="#{viewSelector.modeName}-view.xhtml" />

类似

<h:panelGroup rendered="#{viewSelector.mode == 'HOME'}">
    <ui:include src="home-view.xhtml" />
</h:panelGroup>
<h:panelGroup rendered="#{viewSelector.mode == 'REPORTS'}">
    <ui:include src="reports-view.xhtml" />
</h:panelGroup>
<h:panelGroup rendered="#{viewSelector.mode == 'SUPPORT'}">
    <ui:include src="support-view.xhtml" />
</h:panelGroup>
<h:panelGroup rendered="#{viewSelector.mode == 'HELP'}">
    <ui:include src="help-view.xhtml" />
</h:panelGroup>

类似的问题之前至少被问过一次:)

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