创建JSF定制组件的快速方法

问题描述

我知道创建自定义JSF组件的两种方法:1.本机JSF方式:创建JSF组件类，标签等.2. Facelets方式:在xhtml文件中定义组件，然后在facelets taglib中创建适当的说明.

I know of two ways of creating custom JSF components:1. Native JSF way: creating JSF component class, tag, etc.2. Facelets way: defining component in a xhtml file and then creating appropriate decrption in facelets taglib.

当前，我正在一个项目中，不幸的是引入了facelets.另一方面，以标准JSF方式创建自定义组件似乎很麻烦.

Currently I work on a project in which introducing facelets is unfortunately out of the question. On the other hand, creating custom components the standard JSF way seems like a pain in the ass.

是否存在第三方库，该库允许以类似于facelets的方式创建自定义组件，但不需要使用非标准渲染器?

Is there maybe a third party library that allows creating custom components in the way similar to facelets but doesn't entail the need of using non-standard renderer?

推荐答案

您可以使用(例如) jsp:include 和 f:subview .

You can do a limited amount of templating using (for example) jsp:include and f:subview.

或者，您可以扩展 UIComponent 覆盖选定的方法，然后使用binding属性通过现有标签和托管Bean提供它.这仍然需要对组件开发(以及这种选择的后果)有一个相当详细的了解，但是可能会大大减少文件数量/代码量.

Alternatively, you can extend a UIComponent overriding selected methods and then provide it via an existing tag and a managed bean using the binding attribute. This still requires a reasonably detailed understanding of component development (and the consequences of this choice), but could cut down the number of files/volume of code significantly.

这种方法有点破烂，但对于短期工作来说可能还可以.对于要分发的组件库或需要长期维护的组件，您不会这样做.

This approach is a bit of a hack, but might be OK for short-term stuff. You wouldn't do it for component libraries you want to distribute or components requiring long term maintenance.

新组件:

public class QuickComponent extends HtmlOutputText {
  @Override public void encodeAll(FacesContext context) throws IOException {
    ResponseWriter writer = context.getResponseWriter();
    writer.writeText("I'm not really a HtmlOutputText", null);
    for (UIComponent kid : getChildren()) {
      if (kid instanceof UIParameter) {
        UIParameter param = (UIParameter) kid;
        writer.startElement("br", this);
        writer.endElement("br");
        writer.writeText(param.getName() + "=" + param.getValue(), null);
      }
    }
  }
}

提供实例的bean:

/**Request-scope managed bean defined in faces-config.xml*/
public class QuickComponentProviderBean {
  private QuickComponent quick;

  public void setQuick(QuickComponent quick) {
    this.quick = quick;
  }

  public QuickComponent getQuick() {
    if (quick == null) {
      quick = new QuickComponent();
    }
    return quick;
  }
}

注意:不要在视图中的多个标签上重复使用单个bean属性，否则它们将引用相同的对象实例.

将新组件添加到视图:

<h:outputText binding="#{quickComponentProviderBean.quick}">
  <f:param name="Hello" value="World" />
</h:outputText>

注意:可以定义的属性没有更改.它们由TLD固定.

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