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问JSF MethodExpression没有触发我的backing操作
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Stack Overflow用户

提问于 2009-03-20 10:58:53

回答 2查看 13.2K关注 0票数 2

我的问题是我的代码没有触发我支持bean中的操作。守则如下：

HtmlCommandButton replyCommentButton = new HtmlCommandButton();
replyCommentButton.setId("replyCommentButton" + commentCounter);
replyCommentButton.setValue("Create reply");
String action = "#{Handler.action_replyToComment}";
MethodExpression methodExpression =  
FacesContext.getCurrentInstance().getApplication().getExpressionFactory().
createMethodExpression(FacesContext.getCurrentInstance().getELContext(), action, null,
new Class<?>[0]);
replyCommentButton.setActionExpression(methodExpression);

在我的后台bean RequestHandlerBean (在FacesConfig中定义为Handler )中，我有以下代码：

public void action_replyToComment() {
logger.info("Homemade action called!!!");
System.out.println("Homemade action called!!!");
}

有人注意到为什么当我点击按钮时什么都不会发生吗？它没有正确地触发事件。html代码的来源如下：

<input id="replyCommentButton1" type="submit" value="Create reply"   
name="replyCommentButton1"/>

正如我们所看到的，HTML中没有定义任何操作。

编辑2:我刚刚在Javadoc中发现我的操作方法必须是一个公共字符串。我现在已经在我的后台bean中更改了这一点，所以我的后台bean中的代码是：

public String action_replyToComment() {
logger.info("Homemade action called!!!");
System.out.println("Homemade action called!!!");
return null;
}

Edit2:我还确保它封装在标记中，但仍然没有运气。元素上不应该有一个action属性吗？

Edit3:我的bean是在faces中定义的，如下所示：

<managed-bean>
<description>
Handles the specific request.
</description>
<managed-bean-name>Handler</managed-bean-name>
<managed-bean-class>no.ngt.tech.rt2.beans.RequestHandlerBean</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>

另外，如果我选择在JSF页面中输出，如下所示：

<a4j:commandButton action="#{Handler.action_replyToComment}" value="Reply" />

工作得很好

编辑4-我的JSP页面 Note我现在也尝试过使用贬值的setAction(methodBinding)，但遗憾的是，它也没有起作用。

<%@ include file="_includes.jsp" %>
<f:view>
<html>
<head>
<title><h:outputText value="#{msgs.title}" /></title>
</head>
<body>
<br /><br /><br />



<%@ include file="_menu.jsp" %>

<rich:tabPanel switchType="client">

<rich:tab id="commentsTab" label="Comments" rendered="#{Handler.editRequest}">
<h:form>
         <ngt:commentTree binding="#{Handler.commentTree}" value="#{Handler.comments}"  />

         <br />

         <a4j:commandButton action="#{Handler.action_replyToComment}" value="testbutton" />
</h:form>    
</rich:tab>


</rich:tabPanel>

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

menu.jsp:

<h:form>
    <rich:toolBar itemSeparator="line" styleClass="toolbar" contentClass="toolbar" height="22">
        <rich:toolBarGroup>
            <rich:menuItem submitMode="server" value="Front" action="#{newRT.action_showFront}" />
        </rich:toolBarGroup>
        <rich:toolBarGroup>
            <rich:menuItem submitMode="server" value="New request" action="#{Step.action_showSteps}" />
        </rich:toolBarGroup>
        <rich:toolBarGroup>
            <rich:menuItem submitMode="server" value="Requests" action="#{Handler.action_showRequestsView}" />
        </rich:toolBarGroup>
        <rich:toolBarGroup>
            <rich:menuItem submitMode="server" value="Control-panel" action="#" />
        </rich:toolBarGroup>
        <rich:toolBarGroup location="right">
            <h:inputText styleClass="barsearch" value="#{Handler.search}" />
            <a4j:commandButton styleClass="barsearchbutton" action="#{Handler.action_GetRequestFromID}"  value="Search" />
        </rich:toolBarGroup>
    </rich:toolBar>
</h:form>


<br/><br/>

Includes.jsp

<%@ taglib prefix="h" uri="http://java.sun.com/jsf/html" %>
<%@ taglib prefix="f" uri="http://java.sun.com/jsf/core" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="a4j" uri="http://richfaces.org/a4j" %>
<%@ taglib prefix="rich" uri="http://richfaces.org/rich"%>
<%@ taglib prefix="ngt" uri="http://MySpecialTagLib.no/"%>

编辑7- UIComponent:的Java代码

这是CommentsTreeUI.java：

public class CommentsTreeUI extends UIOutput {

    private static Logger logger = Logger.getLogger(CommentsTreeUI.class.getName());

    @Override
    public void encodeBegin(FacesContext context) throws IOException {

        List<CommentTag> value = (List<CommentTag>) getAttributes().get("value");
        int commentCounter = 0;

        if (value != null) {
            for (CommentTag comment : value) {
                commentCounter++;
                ResponseWriter commentContainerWriter = context.getResponseWriter();
                commentContainerWriter.startElement("div", this);
                commentContainerWriter.writeAttribute("id", "Comment" + commentCounter, null);

                String width = comment.getWidth();
                String height = comment.getHeight();

                String style = comment.getStyle();

                style = (style != null) ? style + ";" : "";

                if (width != null) {
                    style += "width:" + width + ";";
                }
                if (height != null) {
                    style += "height:" + height + ";";
                }

                commentContainerWriter.writeAttribute("style", style, null);

                String newComment = comment.getNewComment();
                if (newComment == null) {
                    newComment = "false";
                }

                String level = comment.getLevel();

                if (level != null) {
                    level = "commentContainerLevel" + level + newComment;
                }
                commentContainerWriter.writeAttribute("class", level, null);

                String title = comment.getTitle();
                if (title != null) {
                    commentContainerWriter.writeAttribute("title", title, null);
                }

                String titleText = comment.getTitleText();
                if (titleText != null) {
                    ResponseWriter titleTextWriter = context.getResponseWriter();
                    UIOutput titleTextComponent = new UIOutput();
                    titleTextWriter.startElement("div", titleTextComponent);
                    titleTextWriter.writeAttribute("class", "commentHeaderText" + newComment, null);
                    titleTextWriter.writeText(titleText + " | ", null);
                    titleTextWriter.startElement("a", titleTextComponent);
                    titleTextWriter.writeAttribute("onclick", "showCommentReply('CommentReply" + commentCounter + "')", null);
                    titleTextWriter.writeAttribute("class", "reply", null);
                    titleTextWriter.writeText("Reply", null);
                    titleTextWriter.endElement("a"); 
                    titleTextWriter.endElement("div");
                }

                String commentBody = comment.getCommentBody();
                if (commentBody != null) {
                    ResponseWriter commentBodyWriter = context.getResponseWriter();
                    UIOutput commentBodyComponent = new UIOutput();
                    commentBodyWriter.startElement("div", commentBodyComponent);
                    commentBodyWriter.writeText(commentBody, null);
                    commentBodyWriter.endElement("div");
                }

                ResponseWriter replyContainerWriter = context.getResponseWriter();
                UIOutput replyContainerComponent = new UIOutput();
                replyContainerWriter.startElement("div", replyContainerComponent);
                commentContainerWriter.writeAttribute("id", "CommentReply" + commentCounter, null);
                replyContainerWriter.writeAttribute("class", "replyContainer", null);

                ResponseWriter replyHeaderWriter = context.getResponseWriter();
                UIOutput replyHeaderComponent = new UIOutput();
                replyHeaderWriter.startElement("div", replyHeaderComponent);
                replyHeaderWriter.writeAttribute("class", "replyHeaderContainer", null);
                replyHeaderWriter.endElement("div");

                ResponseWriter replyFormWriter = context.getResponseWriter();
                UIInput replyFormComponent = new UIInput();
                replyFormWriter.startElement("fieldset", replyFormComponent);
                replyFormWriter.startElement("textarea", replyFormComponent);
                replyFormWriter.writeAttribute("type", "textarea", null);
                replyFormWriter.writeAttribute("rows", "5", null);
                replyFormWriter.writeAttribute("cols", "76", null);
                replyFormWriter.writeText("Write your answer here", null);
                replyFormWriter.endElement("textarea");


                //TODO: Fix so button has action to backing bean
                HtmlAjaxCommandButton replyCommentButton = new HtmlAjaxCommandButton();
                replyCommentButton.setId("replyCommentButton" + commentCounter);
                replyCommentButton.setValue("Create reply");
                String action = "#{RequestHandlerBean.action_replyToComment}";
                //replyCommentButton.setReRender("commentsTree");
                ExpressionFactory factory = context.getApplication().getExpressionFactory();
                Class [] argtypes=new Class[1];
                argtypes[0]=ActionEvent.class;

                MethodExpression replyActionExpression = factory.createMethodExpression(context.getELContext(), action, null, argtypes);
                replyCommentButton.setActionExpression(replyActionExpression);

                MethodExpression methodExpression = context.getCurrentInstance().getApplication().getExpressionFactory().
                        createMethodExpression(context.getCurrentInstance().getELContext(), action, null, new Class<?>[0]);
                replyCommentButton.setActionExpression(methodExpression);
                /*
                replyCommentButton.setAction(context.getApplication().createMethodBinding(action, argtypes));
                */

                replyCommentButton.encodeAll(context);
                //Todo above


                replyFormWriter.writeText(" ", null);
                replyFormWriter.startElement("input", replyFormComponent);
                replyFormWriter.writeAttribute("type", "button", null);
                replyFormWriter.writeAttribute("value", "Cancel ", null);
                replyFormWriter.writeAttribute("onclick", "hideCommentReply('CommentReply" + commentCounter + "')", title);
                replyFormWriter.endElement("input");
                replyFormWriter.endElement("fieldset");
                replyContainerWriter.endElement("div");
                commentContainerWriter.endElement("div");
            }
        } else { //value==null
            ResponseWriter writer = context.getResponseWriter();
            writer.startElement("div", this);

            writer.writeAttribute("id", getClientId(context), null);

            String width = (String) getAttributes().get("width");
            String height = (String) getAttributes().get("height");

            String style = (String) getAttributes().get("style");

            style = (style != null) ? style + ";" : "";

            if (width != null) {
                style += "width:" + width + ";";
            }
            if (height != null) {
                style += "height:" + height + ";";
            }

            writer.writeAttribute("style", style, null);

            String styleClass = (String) getAttributes().get("styleClass");
            if (styleClass != null) {
                writer.writeAttribute("class", styleClass, null);
            }

            String title = (String) getAttributes().get("title");
            if (title != null) {
                writer.writeAttribute("title", title, null);
            }

        }
    }

    @Override
    public void encodeEnd(FacesContext context) throws IOException {
        ResponseWriter writer = context.getResponseWriter();
        writer.endElement("div");
    }

这是CommenstTreeTag：

public class CommentsTreeTag extends UIComponentTag {

    String style;
    String styleClass;
    String title;
    String width;
    String height;
    String value;
    Long parentId;

    public void release() {
        // the super class method should be called
        super.release();
        style = null;
        styleClass = null;
        title = null;
        height = null;
        width = null;
        parentId = null;
        value = null;
    }

    @Override
    protected void setProperties(UIComponent component) {
        // the super class method should be called
        super.setProperties(component);

        if (style != null) {
            component.getAttributes().put("style", style);
        }

        if (styleClass != null) {
            component.getAttributes().put("styleClass", styleClass);
        }

        if (width != null) {
            component.getAttributes().put("width", width);
        }

        if (height != null) {
            component.getAttributes().put("height", height);
        }

        if (title != null) {
            if (isValueReference(title)) {
                ValueBinding vb =
                        getFacesContext().getApplication().createValueBinding(title);
                component.setValueBinding("title", vb);
            } else {
                component.getAttributes().put("title", title);
            }
        }
        if (value != null) {
            if (isValueReference(value)) {
                ValueBinding vb =
                        getFacesContext().getApplication().createValueBinding(value);
                component.setValueBinding("value", vb);
                getFacesContext().getApplication().createValueBinding(value);

            } else {
                component.getAttributes().put("value", value);
            }
        }
        if (parentId != null) {
            component.getAttributes().put("parentId", parentId);
        }
    }



    public String getComponentType() {
        return "commentTree";
    }

    public String getRendererType() {
        // null means the component renders itself
        return null;
    }

    public String getHeight() {
        return height;
    }

    public void setHeight(String height) {
        this.height = height;
    }

    public String getWidth() {
        return width;
    }

    public void setWidth(String width) {
        this.width = width;
    }

    public String getStyle() {
        return style;
    }

    public void setStyle(String style) {
        this.style = style;
    }

    public String getStyleClass() {
        return styleClass;
    }

    public void setStyleClass(String styleClass) {
        this.styleClass = styleClass;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }
}

jsf

methods

uicomponents

回答 2

Stack Overflow用户

回答已采纳

发布于 2009-03-24 10:16:04

我认为您遇到的问题是由于您在JSF组件树中添加commandButton的方式，或者更确切地说，是uou不将它添加到组件树中的方式。

由于您没有将commandButton附加到JSF树，所以当呈现该组件时(通过调用.encodeAll()方法)，它找不到该组件嵌套的表单。因此，HTML输入没有正确创建。

在请求呈现表单之前，您可以尝试将创建的commandButton直接添加到表单中。您可以使用以下代码执行此操作：

// Search for the component HtmlForm that is a (in)direct parent of the current component
private UIComponent getCurrentForm(UIComponent currentComponent) {
    UIComponent parent = currentComponent.getParent();
    while ((parent != null) && !(parent instanceof HtmlForm)) {
        parent = parent.getParent();
    }
    return parent;
}


public void encodeBegin(FacesContext context) throws IOException {
    ...
    HtmlAjaxCommandButton replyCommentButton = new HtmlAjaxCommandButton();
    ...

    // Add the command button in the form that contains your custom component...
    UIComponent form = getCurrentForm(this);
    if (form != null) {
        form.getChildren().add(replyCommentButton);
    }
    replyCommentButton.encodeAll(context);
    ...
}

请注意，我已经测试了这段代码，所以您可能需要修改一下.

如果它仍然不能工作，也许您需要检查您的代码，以便在render类或encodeBegin之外创建该encodeBegin.我不认为在呈现阶段修改JSF组件树是个好主意。

票数 3

Stack Overflow用户

发布于 2009-03-20 11:13:45

您的代码似乎是正确的(实际上，该方法必须返回一个字符串，但它也可以返回void，即使不需要重新编写这样的操作方法)。

您确定创建的commandButton是嵌套在组件中的吗？否则，它就行不通了。我的意思是(不管是在Java或JSF页面中创建的)，必须有一个直接或间接的父级(在JSF组件树中)。例如：

<h:form>
  ...
  <h:commandButton .../>
  ...
</h:form>

单击此问题时，您是否有Javascript错误？

编辑有关评论。

编辑2，关于我对主要帖子的评论：

也许您可以尝试用旧的方式将操作附加到按钮上(好的，这是不推荐的，但只需尝试一下)：

replyCommandButton.setAction(context.getApplication().createMethodBinding("#{Handler.action_replyToComment}", null));

票数 1

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/665685

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