java 自定义 JSP 标记 - 如何获取标记的正文？
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Custom JSP tag - How do I get the body of the tag?
提问by Kyle
I have a custom jsp tag like this:
我有一个像这样的自定义 jsp 标签：
<a:customtag>
The body of the custom tag...
More lines of the body...
</a:customtag>
In the custom tag, how can I get the text of what the body is?
在自定义标签中，如何获取正文的文本？
回答by brabster
It's complicated because there are two mechanisms.
这很复杂，因为有两种机制。
If you're extending SimpleTagSupport, you get getJspBody()method. It returns a JspFragment that you can invoke(Writer writer)to have the body content written to the writer.
如果您要扩展 SimpleTagSupport，您将获得getJspBody()方法。它返回一个 JspFragment，您可以调用它(Writer writer)将正文内容写入编写器。
You should use SimpleTagSupport unless you have a specific reason to use BodyTagSupport (like legacy tag support) as it is - well - simpler.
您应该使用 SimpleTagSupport ，除非您有特定的理由使用 BodyTagSupport（如旧标签支持），因为它 - 好吧 - 更简单。
If you areusing classic tags, you extend BodyTagSupport and so get access to a getBodyContent()method. That gets you a BodyContent object that you can retrieve the body content from.
如果您正在使用经典的标签，您扩展BodyTagSupport等获得访问getBodyContent（）方法。这将为您提供一个 BodyContent 对象，您可以从中检索正文内容。
回答by Alireza Fattahi
If you are using a custom tag with jsp 2.0 approach, you can do it as:
如果您使用带有 jsp 2.0 方法的自定义标记，您可以这样做：
make-h1.tag
make-h1.tag
<%@tag description="Make me H1 " pageEncoding="UTF-8"%>
<h1><jsp:doBody/></h1>
Use it in JSP as:
在 JSP 中使用它作为：
<%@ taglib prefix="t" tagdir="/WEB-INF/tags"%>
<t:make-h1>An important head line </t:make-h1>
回答by brasskazoo
To expand on Brabster's answer, I've used SimpleTagSupport.getJspBody()to write the JspFragmentto an internal StringWriterfor inspection and manipulation:
为了扩展Brabster 的答案，我曾经SimpleTagSupport.getJspBody()将 写入JspFragment内部StringWriter以进行检查和操作：
public class CustomTag extends SimpleTagSupport {
@Override public void doTag() throws JspException, IOException {
final JspWriter jspWriter = getJspContext().getOut();
final StringWriter stringWriter = new StringWriter();
final StringBuffer bodyContent = new StringBuffer();
// Execute the tag's body into an internal writer
getJspBody().invoke(stringWriter);
// (Do stuff with stringWriter..)
bodyContent.append("<div class='custom-div'>");
bodyContent.append(stringWriter.getBuffer());
bodyContent.append("</div>");
// Output to the JSP writer
jspWriter.write(bodyContent.toString());
}
}
}
}
