struts2自定义tag

package com.exam.taglib.table;     
    
import org.apache.struts2.components.UIBean;     
import org.apache.struts2.views.annotations.StrutsTag;     
import org.apache.struts2.views.annotations.StrutsTagAttribute;     
import com.opensymphony.xwork2.util.ValueStack;     
    
import javax.servlet.http.HttpServletRequest;     
import javax.servlet.http.HttpServletResponse;     
    
/**   
* struts2版的分页标签   
*    
*/    
    
@StrutsTag(name = "pager", tldTagClass = "org.icim.pager.struts2.PagerTag", description = "struts2 pager by ithink")     
public class Pager extends UIBean {     
    
    final public static String TEMPLATE = "pager";     
    
    protected String totalRecord;     
    protected String totalPage;     
    protected String curPage;     
    protected String pageLimit;     
    protected String url;     
    protected String curCssClass;     
    protected String showTotalPage;     
    protected String showTotalRecord;     
    protected String directJumpType;     
    
    public Pager(ValueStack stack, HttpServletRequest request,     
            HttpServletResponse response) {     
        super(stack, request, response);     
    }     
    
    /**   
     * 用于返回模板的名字，Struts2会自动在后面加入.ftl扩展名以找到特定的模板文件。   
     */    
    @Override    
    protected String getDefaultTemplate() {     
        return TEMPLATE;     
    }     
    
    /**   
     * 设置UIBean的属性，一般Tag中有几个这样的属性，这里就有几个 StrutsTagAttribute注解，说明该属性是int类型，这一步很重要   
     *    
     * @param totalPage   
     */    
    
    @StrutsTagAttribute(description = "total records", type = "Long")     
    public void setTotalRecord(String totalRecord) {     
        this.totalRecord = totalRecord;     
    }     
    
    @StrutsTagAttribute(description = "total pages", type = "Integer")     
    public void setTotalPage(String totalPage) {     
        this.totalPage = totalPage;     
    }     
    
    @StrutsTagAttribute(description = "current page", type = "Integer")     
    public void setCurPage(String curPage) {     
        this.curPage = curPage;     
    }     
    
    @StrutsTagAttribute(description = "how many pages in a panel once", type = "Integer")     
    public void setPageLimit(String pageLimit) {     
        this.pageLimit = pageLimit;     
    }     
    
    @StrutsTagAttribute(description = "url to be linked", type = "String")     
    public void setUrl(String url) {     
        this.url = url;     
    }     
    
    @StrutsTagAttribute(description = "css style of current page", type = "String")     
    public void setCurCssClass(String curCssClass) {     
        this.curCssClass = curCssClass;     
    }     
    
    @StrutsTagAttribute(description = "whether to show totalPage", type = "Boolean", defaultValue = "true")     
    public void setShowTotalPage(String showTotalPage) {     
        this.showTotalPage = showTotalPage;     
    }     
    
    @StrutsTagAttribute(description = "whether to show currentPage", type = "Boolean", defaultValue = "false")     
    public void setShowTotalRecord(String showTotalRecord) {     
        this.showTotalRecord = showTotalRecord;     
    }     
    
    // TODO 直接页面跳转     
    // 这里的directJumpType默认值为none， 可选值为 'select', 'goto'     
    @StrutsTagAttribute(description = "show type of direct jump type. such as select,textbox which can lead going to a page directly", type = "String", defaultValue = "none")     
    public void setDirectJumpType(String directJumpType) {     
        this.directJumpType = directJumpType;     
    }     
    
    /**   
     * 重写evaluateExtraParams（）方法，在UIBean初始化后会调用这个方法来初始化设定参数，如addParameter方法，会在freemarker里的parameters里加入一个key   
     * value。这里要注意findString，还有相关的findxxxx方法，它们是已经封装好了的解释ognl语法的工具，具体是怎么样的，大家可以查看一下UIBean的api   
     * doc   
     */    
    @Override    
    protected void evaluateExtraParams() {     
        super.evaluateExtraParams();     
        // findValue()方法本身已对OGNL进行了处理     
    
        if (totalRecord != null) {     
            addParameter("totalRecord", findValue(totalRecord));     
        }     
    
        if (totalPage != null) {     
            addParameter("totalPage", findValue(totalPage));     
        }     
    
        if (curPage != null) {     
            addParameter("curPage", findValue(curPage));     
        }     
    
        if (pageLimit != null) {     
            addParameter("pageLimit", findValue(pageLimit));     
        }     
    
        if (url != null) {     
            addParameter("url", findValue(url, String.class));     
        }     
    
        if (curCssClass != null) {     
            addParameter("curCssClass", findValue(curCssClass,String.class));     
        }     
    
        if (showTotalPage != null) {     
            addParameter("showTotalPage", findValue(showTotalPage,     
                    Boolean.class));     
        }     
    
        if (showTotalRecord != null) {     
            addParameter("showTotalRecord", findValue(showTotalRecord,Boolean.class));     
        }     
    
        if (directJumpType != null) {     
            addParameter("directJumpType", findValue(directJumpType));     
        }     
    
    }     
}   

载自http://code.google.com/p/chinese-exam/source/browse/trunk/exam/src/com/exam/taglib/table/Pager.java?r=2