guesttag.java

Java Web 开发使用标签的一个综合例子

package zengjsp;
//本程序定义tag 的start body 和end

import java.io.*;
import java.util.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import javax.servlet.jsp.tagext.BodyTagSupport;

public class GuestTag extends BodyTagSupport {
  private String  name,gender,tele,mail;
  private zengjsp.GuestDB db;
  private zengjsp.GuestBean  guest;
  private Iterator it;

  public int doStartTag(){
   try{
    db = new zengjsp.GuestDB() ;
     ArrayList list = db.getGuestList() ;
     it = list.iterator() ;
     if(it.hasNext() ){
        nextMan();
        return EVAL_BODY_TAG;//如果有数据，则继续前进
     }
     else
        return SKIP_BODY;

   }catch(Exception e){ e.printStackTrace() ; return SKIP_BODY;}
  }//do start tag

 public int doAfterBody(){
   try{
       bodyContent.writeOut(getPreviousOut())      ;
   }catch(IOException e){ e.printStackTrace() ; return SKIP_BODY;}
 bodyContent.clearBody() ;
 if(it.hasNext() ){
   nextMan();
   return EVAL_BODY_TAG;
 }//uif
 else
   return SKIP_BODY;

 }//afterbody

  private void nextMan(){
    guest = (zengjsp.GuestBean) it.next() ;
    pageContext.setAttribute("name",guest.getName() );
    pageContext.setAttribute("gender",guest.getGender() );
    pageContext.setAttribute("tele",guest.getTele() );
    pageContext.setAttribute("mail",guest.getMail() );
  }//next Man
}