实际意义： 就是在页面中从3开始，循环输出 时间
 
package com.randy.tag;

import java.io.IOException;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;

public class BodyTag extends BodyTagSupport {

    
  private int countNum =0;//循环显示时间的次数
  private int currentNum =1;//当前执行次数
    
  @Override
  public int doAfterBody() throws JspException {


    try {
      JspWriter out = pageContext.getOut();
      out.println("第"+currentNum+"次执行标签体。标签体执行完毕。<br/>");
        
      if(countNum >1){
        countNum--;
        currentNum ++;
        return EVAL_BODY_TAG;
      }else{
        return SKIP_BODY;
      }
    } catch (IOException e) {
      e.printStackTrace();
      return SKIP_BODY;
    }
  }

  @Override
  public int doEndTag() throws JspException {
    
    try {
      JspWriter out = pageContext.getOut();
      bodyContent.writeOut(bodyContent.getEnclosingWriter());//输出标签体的内容
      out.println("标签结束了");
    } catch (IOException e) {
      e.printStackTrace();
    }
    return EVAL_PAGE;
  }

  @Override
  public void doInitBody() throws JspException {

    currentNum=3;
    super.doInitBody();
  }

  @Override
  public int doStartTag() throws JspException {
      try {
        JspWriter out = pageContext.getOut();
        out.println("标签开始了:<br/>");
        
        if(countNum>0){
          return EVAL_BODY_TAG;
        }else{
          return SKIP_BODY;
        }
      } catch (IOException e) {
        e.printStackTrace();
        return SKIP_BODY;
      }
    
  }

  public int getCountNum() {
    return countNum;
  }

  public void setCountNum(int countNum) {
    this.countNum = countNum;
    this.currentNum =1;
  }

    
    
}
 
 
tld
  <tag>
    <description>含有标签体</description>
    <name>bodyTag</name>
    <tag-class>com.randy.tag.BodyTag</tag-class>
    <body-content>JSP</body-content>
    
    <attribute>
      <name>countNum</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
    </attribute>
  </tag>
 
注意JSP 的大写。 书上写的是小写，不对。
 
<myTag:bodyTag countNum="6">
  <%= new java.util.Date() %>
</myTag:bodyTag>