这两天看了下struts标签
蛋疼呀。。。如果不是必要。还是不要用struts标签。。。哎!
先说下struts标签的继承
BodyTagSupport
StrutsBodyTagSupport
ComponentTagSupport
AbstractUITag
每个struts标签都继承AbstractUITag
重点是ComponentTagSupport:
import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.jsp.JspException; import org.apache.struts2.components.Component; import org.apache.struts2.dispatcher.Dispatcher; import com.opensymphony.xwork2.inject.Container; import com.opensymphony.xwork2.util.ValueStack; public abstract class ComponentTagSupport extends StrutsBodyTagSupport { protected Component component; // 定义一个组件(虚方法) public abstract Component getBean(ValueStack stack, HttpServletRequest req, HttpServletResponse res); public int doEndTag() throws JspException { component.end(pageContext.getOut(), getBody()); component = null; return EVAL_PAGE; } public int doStartTag() throws JspException { // 获取组件 component = getBean(getStack(), (HttpServletRequest) pageContext.getRequest(), (HttpServletResponse) pageContext.getResponse()); Container container = Dispatcher.getInstance().getContainer(); container.inject(component); // 填充参数 populateParams(); // 组件开始 boolean evalBody = component.start(pageContext.getOut()); if (evalBody) { return component.usesBody() ? EVAL_BODY_BUFFERED : EVAL_BODY_INCLUDE; } else { return SKIP_BODY; } } protected void populateParams() { } public Component getComponent() { return component; } }
如果自定义struts标签,那么一定要看这类的源码。这里记录下。。。