jsp自定义标签写法

页面引用：

<%@ taglib uri="/WEB-INF/abc.tld" prefix="aa" %>
...
<aa:mytag .../>

tld:

<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.0">
	<tlib-version>1.0</tlib-version>
	
	<tag>
		<name>adv</name>
		<tagclass>com.mb.util.Advertisement</tagclass>
		<attribute>
			<name>placeId</name>
			<required>true</required>
		</attribute>
	</tag>
</taglib>

java:

public class Advertisement extends TagSupport {

	/**  */
	private static final long serialVersionUID = -1701876066227050270L;
	/** 广告位ID */
	private String placeId;

	public int doEndTag() throws JspException {
		String path = pageContext.getServletContext().getRealPath("/");
		Long cityID = ((City) pageContext.getSession().getAttribute("city")).getId();
		cityID = 1L;
		// 得到广告位id
		AdvdeployDAO dao = (AdvdeployDAO) BeanProxy.getBean("advDeployDAO");
		AdvDeploy advdeploy = dao.getAdvdeploy("" + cityID, placeId, "0");
		StringBuilder sb = new StringBuilder();
		String advStr = "";
		if (advdeploy != null) {
			Adv adv = advdeploy.getAdv();
			String advalt = "";
			String imgurl = "";
			Long advid = 0L;
			if (adv != null) {
				advalt = adv.getAlt();
				imgurl = adv.getImgurl();
				advid = adv.getId();
			}

			// 根据位置查看是不是滚动广告
			Advplace ap = advdeploy.getPc().getAdvplace();
			if (imgurl.endsWith(".swf")) {
				sb.append("<embed src='#path#imgurl' width='#width' height='#height'/>");
			} else {
				sb.append("<a href='#path/updateAdvClickNum.mb?id=#id&cityID=#cityID' target='_blank'>");
				sb.append("<img alt='#alt' src='#path#imgurl' width='#width' height='#height'/>");
				sb.append("</a>");
			}
			advStr = sb.toString();
			advStr = advStr.replace("#id", advid + "");
			advStr = advStr.replace("#cityID", cityID + "");
			advStr = advStr.replace("#alt", advalt);
			advStr = advStr.replace("#path", path);
			advStr = advStr.replace("#imgurl", imgurl);
			advStr = advStr.replace("#width", ap.getWidth() + "");
			advStr = advStr.replace("#height", ap.getHeight() + "");

		}
		JspWriter jw = pageContext.getOut();
		try {
			jw.println(advStr);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return SKIP_BODY;
	}

	/**
	 * @return the placeId
	 */
	public String getPlaceId() {
		return placeId;
	}

	/**
	 * @param placeId the placeId to set
	 */
	public void setPlaceId(String placeId) {
		this.placeId = placeId;
	}

}