了解struts2自定义标签的请进

我在WEB-INF目录下创建了tags.tlb内容如下
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
    <tlib-version>2.2.3</tlib-version>
    <jsp-version>1.2</jsp-version>
    <short-name>tags</short-name>
    <uri>/tags</uri>
    <display-name>"Tangs Tags"</display-name>
        <tag>
            <name>pages</name>
            <tag-class>com.Tag</tag-class>     
            <body-content>empty</body-content>
            <attribute>      
                <name>th</name>      
                <required>true</required>      
                <rtexprvalue>true</rtexprvalue>    
            </attribute>
        </tag>
</taglib>
然后创建了两个JAVA类分别继承了自定义标签的ComponentTagSupport，Component
第一个是ComponentTagSupport
public Component getBean(ValueStack arg0, HttpServletRequest arg1,
HttpServletResponse arg2) {
System.out.println("getBean");
System.out.println("t:"+th);
return new Tt1(arg0);
}

    protected void populateParams() {
       super.populateParams();
     System.out.println(th);
        System.out.println("populateParams");
        Tt1 tt = (Tt1)component;
        tt.setT1(t1);
        tt.setTh(th);
    }
第二个是Component
public boolean start(Writer writer) {
boolean result = super.start(writer);
try{
System.out.println("start");
Double d=null;
DecimalFormat df=null;
System.out.println(t1);
System.out.println(th);
if(t1.startsWith("%{")&&t1.endsWith("}")){
System.out.println(t1);
d = new Double(t1);
System.out.println(d.toString());
df=new DecimalFormat( "###,###.## ");
}
System.out.println(df.format(d).toString());
writer.write(df.format(d).toString());
}catch(Exception ex){
ex.printStackTrace();
}
return result;
}
页面代码
"S2：" <s:property value="t1"/><br>
"自定义：" <u:pages th="%{t1 }"/>

action 代码
public String execute() throws Exception{
t1="3331000.00";
System.out.println("dd");
return "input";
    }
但是自定义标签不是t1传入后台的参数不是3331000.00而是%{t1} --------------------编程问答-------------------- 没人懂吗？？？ --------------------编程问答-------------------- 他们提供的都已经够用了，自定义标签没有搞过

补充：Java ,  Web 开发