JSP SimpleTag：未调用body标记

Question

我有一个非常简单的JSP标记来生成一个面板。

标签正在扩展SimpleTagSupport。静态内容呈现正常，但正文中的简单out-tag未正确调用。

public abstract class AbstractTag extends SimpleTagSupport {

private static Logger logger = LoggerFactory.getLogger(AbstractTag.class);

private static final long serialVersionUID = 7666479886150080344L;

private String elementType;
private String htmlID;

private HtmlClassAspect classAspect = new HtmlClassAspect();
private List<AbstractAspect> aspects = new ArrayList<AbstractAspect>();

private AbstractTag surroundingTag;
private List<AbstractTag> beforeBodyChildTags = new ArrayList<AbstractTag>();
private List<AbstractTag> afterBodyChildTags = new ArrayList<AbstractTag>();
private List<AbstractTag> beforeParentChildTags = new ArrayList<AbstractTag>();
private List<AbstractTag> afterParentChildTags = new ArrayList<AbstractTag>();

private boolean isInlineTag = false;

public AbstractTag(String elementType) {
    this.elementType = elementType;
}

public abstract void setupTag();

public void doStartTag() throws JspException, IOException {
    setupTag();
    JspWriter out = getJspContext().getOut();
    // add htmlID if present
    if (!Check.isNull(htmlID)) {
        addAspect(new HtmlIDAspect(htmlID));
    }

    if (surroundingTag != null) {
        this.setParent(surroundingTag);
        surroundingTag.doStartTag();
    }

    // generate open-tag
    if (!Check.isNull(elementType)) {
        out.print("<");
        out.print(elementType);

        // apply class aspect if not empty
        if (classAspect.getValues().size() > 0) {
            classAspect.apply(out);
        }

        // apply aspects
        for (AbstractAspect aspect : aspects) {
            aspect.apply(out);
        }

        // close opening tag
        if (!elementType.equalsIgnoreCase(HTML.DIV)) {
            if (beforeBodyChildTags.size() == 0 && getJspBody() == null && afterBodyChildTags.size() == 0) {
                out.print(" /");
            }
        }

        if(!isInlineTag){
            out.println(">");               
        }else{
            out.print(">");
        }
    }

    for (AbstractTag child : beforeParentChildTags) {
        child.setJspContext(getJspContext());
        child.doTag();
    }
}

public void doEndTag() throws JspException, IOException {
    JspWriter out = getJspContext().getOut();
    // generate close tag if needed
    if (!Check.isNull(elementType)) {
        if (beforeBodyChildTags.size() > 0 || getJspBody() != null || afterBodyChildTags.size() > 0 || elementType.equalsIgnoreCase(HTML.DIV)) {
            out.print("</");
            out.print(elementType);
            out.print(">");
        }
    }
    // generate afterParent child-Tags
    for (AbstractTag child : afterParentChildTags) {
        child.setJspContext(getJspContext());
        child.doTag();
    }
    if (surroundingTag != null) {
        this.setParent(surroundingTag);
        surroundingTag.doEndTag();
        // for (AbstractTag tag : surroundingTag.getAfterParentChildTags())
        // {
        // tag.setJspContext(getJspContext());
        // tag.doTag();
        // }
    }
}

@Override
public void doTag() throws JspException, IOException {
    JspWriter out = getJspContext().getOut();

    doStartTag();

    // before body children
    for (AbstractTag child : beforeBodyChildTags) {
        child.setJspContext(getJspContext());
        child.doTag();
    }

    // body
    if (getJspBody() != null) {
        getJspBody().invoke(null);
    }

    // after body children
    for (AbstractTag child : afterBodyChildTags) {
        child.setJspContext(getJspContext());
        child.doTag();
    }

    doEndTag();
}

public AbstractTag getSurroundingTag() {
    return surroundingTag;
}

public void setSurroundingTag(AbstractTag surroundingTag) {
    this.surroundingTag = surroundingTag;
    this.surroundingTag.setJspContext(getJspContext());
    this.surroundingTag.addChildBeforeBody(this);
}

public void addChildBeforeParent(AbstractTag component) {
    component.setParent(this);
    beforeParentChildTags.add(component);
}

public List<AbstractTag> getBeforeParentChildTags() {
    return beforeParentChildTags;
}

public void addChildBeforeBody(AbstractTag component) {
    component.setParent(this);
    beforeBodyChildTags.add(component);
}

public List<AbstractTag> getBeforeBodyChildTags() {
    return beforeBodyChildTags;
}

public void addChildAfterBody(AbstractTag component) {
    component.setParent(this);
    afterBodyChildTags.add(component);
}

public List<AbstractTag> getAfterBodyChildTags() {
    return afterBodyChildTags;
}

public void addChildAfterParent(AbstractTag component) {
    component.setParent(this);
    afterParentChildTags.add(component);
}

public List<AbstractTag> getAfterParentChildTags() {
    return afterParentChildTags;
}

public void addAspect(AbstractAspect aspect) {
    if (aspect instanceof HtmlClassAspect) {
        throw new IllegalArgumentException("Not allowed to add HtmlClassAspect; use AbstractTag#addClass() instead");
    }
    aspects.add(aspect);
}

public String getHtmlID() {
    return htmlID;
}

public void setHtmlID(String htmlID) {
    this.htmlID = htmlID;
}

public void addClass(String... htmlClass) {
    for (String cls : htmlClass) {
        classAspect.addValue(cls);
    }
}

public void setInlineTag(boolean isInlineTag) {
    this.isInlineTag = isInlineTag;
}

}

JSP：

<%@ page isELIgnored="false" %>
<%@ taglib uri="http://.../taglib/ui" prefix="ui"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

 <c:if test="${not empty errorMsg}">
    <ui:panel type="WARNING" title="Error">
        <c:out value="${error_msg}"/>
    </ui:panel>
</c:if>

HTML输出：

<div class="panel panel-warning">
    <c:out value="${error_msg}"/>
</div>

我现在正在研究这几天......