Question

创建了标记库描述符文件：

 <?xml version="1.0" encoding="UTF-8"?>
    <taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd">
      <tlib-version>1.0</tlib-version>
      <short-name>image</short-name>
      <uri>/WEB-INF/tlds/image</uri>
      <tag>
        <name>BsilImage</name>
        <tag-class>com.custom.image.ImageTagHandler</tag-class>
        <body-content>scriptless</body-content>
        <attribute>
          <name>url</name>
          <required>true</required>
          <rtexprvalue>true</rtexprvalue>
          <type>java.lang.String</type>
        </attribute>
        <attribute>
          <name>style</name>
          <rtexprvalue>true</rtexprvalue>
          <type>java.lang.String</type>
        </attribute>
        <attribute>
          <name>type</name>
          <required>true</required>
          <rtexprvalue>true</rtexprvalue>
          <type>java.lang.String</type>
        </attribute>
      </tag>
    </taglib>

ImageTagHandler

public class ImageTagHandler extends UIComponentELTag {

    private String url;
    private String style;
    private String type;
    private static final String IMAGE_COMP_TYPE = "IMAGE_COMPONENT";
    private static final String IMAGE_RENDERER_TYPE = "IMAGE_RENDERER";

    public void setUrl(String url) {
        this.url = url;
    }

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

    public void setType(String type) {
        this.type = type;
    }

    public String getComponentType() {
        return IMAGE_COMP_TYPE;
    }

    public String getRendererType() {
        return IMAGE_RENDERER_TYPE;
    }

    @Override
    protected void setProperties(UIComponent component) {
        super.setProperties(component);
        ImageComponent imgComponent =
                ((ImageComponent) component);
        if (type != null) {
            imgComponent.setType(ImageTranscoder.getImageTypeOf(type));
        }
        if (url != null) {
            imgComponent.setUrl(ImageTranscoder.getImagePath(url));
        }

        if (style != null) {
            imgComponent.setStyle(style);
        }        
    }
}

ImageComponent

public class ImageComponent extends UIOutput {

    private String url;
    private String style;
    private String type;
    private static final String IMAGE_COMP_FAMILY = "IMAGE_FAMILY";

    @Override
    public String getFamily() {
      return IMAGE_COMP_FAMILY;
  }

    /**
     * Get the value of type
     *
     * @return the value of type
     */
    public String getType() {
        return type;
    }

    /**
     * Set the value of type
     *
     * @param type new value of type
     */
    public void setType(String type) {
        this.type = type;
    }

    /**
     * Get the value of style
     *
     * @return the value of style
     */
    public String getStyle() {
        return style;
    }

    /**
     * Set the value of style
     *
     * @param style new value of style
     */
    public void setStyle(String style) {
        this.style = style;
    }

    /**
     * Get the value of url
     *
     * @return the value of url
     */
    public String getUrl() {
        return url;
    }

    /**
     * Set the value of url
     *
     * @param url new value of url
     */
    public void setUrl(String url) {
        this.url = url;
    }

}

ImageRenderer

public class ImageRenderer extends Renderer {
    @Override
    public void encodeBegin(FacesContext context, UIComponent component)
                    throws IOException {
        ImageComponent imgComponent = (ImageComponent)component;
        ResponseWriter writer = context.getResponseWriter();
        writer.startElement("div",component);
        writer.startElement("img", imgComponent);
        writer.writeAttribute("src",imgComponent.getUrl(), "url");
        writer.writeAttribute("class", imgComponent.getStyle(), "style");
        writer.endElement("div");
    }

}

访问TAG LIB的代码

<h:dataTable var="landing" binding="${LandingBean.tourPackages}" >
       <h:column>
          <tr:panelGroupLayout layout="vertical" styleClass="landingListing">
              <bsil:BsilImage style="listingImage" url="${landing.photoThumbnail}"   type="banner"/>
           </tr:panelGroupLayout>
       </h:column>
</h:dataTable>

bean包含多张照片，在显示页面时必须以列数显示。我面临的问题是它无法向我显示多个图像给出错误说

根据TLD或属性标签文件中的指令，属性绑定不接受任何表达式

如果bean包含单个图像，则显示该代码为

<tr:panelHeader id="panelHeader" styleClass="banner" text="">
                    <bsil:BsilImage url="${LandingBean.bannerImage}"
                        style="bannerImage" type="banner"></bsil:BsilImage>
                </tr:panelHeader>

我想知道如何使用自定义组件显示多个图像。

Answer 1

根据您引用的错误消息，似乎问题出现在<h:dataTable ...>标记中，似乎其属性称为“绑定”显然由于某种原因不接受表达式。

E.g。

<tag> 

    <name>dataTable</name> 

    <attribute> 
      <name>binding</name>
      <!-- add this: --> 
      <rtexprvalue>true</rtexprvalue>
    </attribute>

</tag>

如果您拥有dataTable标记的代码，请在该标记的“绑定”属性旁边添加<rtexprvalue>true</rtexprvalue>（就像您在图片标记中所做的那样）。如果不这样做，请参阅它的文档并找出它不允许表达式的原因。

JSF自定义图像组件显示多个图像的问题

1 个答案: