struts标签logic:iterate学习

转载(http://www.java3z.com/cwbwebhome/article/article1a/171.html?id=364)

 在逻辑标记库中定义了 < logic:iterate > 标记，它能够根据特定集合中元素的数目对标记体的内容进行重复的检查。集合的类型可以是java.util.Iterator,java.util.Collection,java.util.Map
或是一个数组，也可以用name属性定义一个bean,并且使用property属性指定要循环的bean的属性（这个属性返回集合）类型。 

下面请看struts1. 2 .4中自带的例子： 

<% @ taglib uri = " /tags/struts-bean "  prefix = " bean "   %>  
<% @ taglib uri = " /tags/struts-logic "  prefix = " logic "   %>  
< html >  
   < head >  
     < title > 测试struts - logic Iterate 标记 </ title >  
   </ head >  
   < body bgcolor = " white " >    

     <%  
      { 
        java.util.ArrayList list  =   new  java.util.ArrayList(); 
        list.add( " First " ); 
        list.add( " Second " ); 
        list.add( " Third " ); 
        list.add( " Fourth " ); 
        list.add( " Fifth " ); 
        pageContext.setAttribute( " list " , list, PageContext.PAGE_SCOPE); 

         int  intArray[]  =   new   int [] 
         {  0 ,  10 ,  20 ,  30 ,  40  }; 
        pageContext.setAttribute( " intArray " , intArray, PageContext.PAGE_SCOPE); 
      } 
     %>  
     < div align = " center " >  
       < h1 > 测试struts - logic Iterate标记 </ h1 >  
     </ div >  
     < jsp:useBean id = " bean "  scope = " page "   class = " org.apache.struts.webapp.exercise.TestBean "   />  
     < jsp:useBean id = " list "  scope = " page "   class = " java.util.ArrayList "   />  

     < h3 > 测试1  -  从头到尾叠代（循环）一个字符串数组[ 0 .. 4 ] </ h3 >  

     < ul >  
       <!-- 用name属性指定一个bean,property属性指定要循环的bean的属性,id集合中当前元素的句柄，index1保存当前索引值 -->  
       < logic:iterate id = " element "  name = " bean "  property = " stringArray "  indexId = " index1 " >  
         < li >  
         < em >  
           < bean:write name = " element "   />  
         </ em >  [ 
         < bean:write name = " index1 "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  

     < h3 > 测试2  -  叠代一个字符串数组（循环三次）Array [ 0 .. 2 ] </ h3 >  
     < ul >  
       < logic:iterate id = " element "  name = " bean "  property = " stringArray "  indexId = " index "  length = " 3 " >  
         < li >  
         < em >  
           < bean:write name = " element "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  
     < h3 > 测试3  -  叠代一个String Array [ 3 .. 4 ]（输出索引从3开始的元素） </ h3 >  
     < ul >  
       < logic:iterate id = " element "  name = " bean "  property = " stringArray "  indexId = " index "  offset = " 3 " >  
         < li >  
         < em >  
           < bean:write name = " element "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  
     < h3 > 测试4  -  叠代一个String Array [ 1 .. 3 ] </ h3 >  
     < ul >  
       < logic:iterate id = " element "  name = " bean "  property = " stringArray "  indexId = " index "  offset = " 1 "  length = " 3 " >  
         < li >  
         < em >  
           < bean:write name = " element "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  
     < h3 > 测试5  -  从头至尾叠代一个Array List </ h3 >  
     < ul >  
       < logic:iterate id = " item "  name = " list "  indexId = " index " >  
         < li >  
         < em >  
           < bean:write name = " item "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  
     < h3 > 测试6  -  叠代一个Array List [ 0 .. 2 ] </ h3 >  
     < ol >  
       < logic:iterate id = " item "  name = " list "  indexId = " index "  offset = " 0 "  length = " 3 " >  
         < li >  
         < em >  
           < bean:write name = " item "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ol >  
     < h3 > 测试7  -  叠代一个Array List [ 2 .. 4 ] </ h3 >  
     < ol >  
       < logic:iterate id = " item "  name = " list "  indexId = " index "  offset = " 2 "  length = " 3 " >  
         < li >  
         < em >  
           < bean:write name = " item "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ol >  
     < h3 > 测试8  -  叠代一个int array </ h3 >  
     < ul >  
       < logic:iterate id = " item "  name = " intArray "  indexId = " index " >  
         < li >  
         < em >  
           < bean:write name = " item "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  
     < h3 > 测试  9   -  叠代一个int array [ 0 .. 2 ] </ h3 >  
     < ul >  
       < logic:iterate id = " item "  name = " intArray "  indexId = " index "  length = " 3 " >  
         < li >  
         < em >  
           < bean:write name = " item "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  
     < h3 > 测试10  -  叠代一个int array [ 2 .. 4 ] </ h3 >  
     < ul >  
       < logic:iterate id = " item "  name = " intArray "  indexId = " index "  offset = " 2 "  length = " 3 " >  
         < li >  
         < em >  
           < bean:write name = " item "   />  
         </ em >  [ 
         < bean:write name = " index "   /> ] </ li >  
       </ logic:iterate >  
     </ ul >  
   </ body >  
</ html >  

下面是TestBean.java的部分： 


package  org.apache.struts.webapp.exercise; 


import  java.util.ArrayList; 
import  java.util.Collection; 
import  java.util.HashMap; 
import  java.util.List; 
import  java.util.Map; 
import  java.util.Vector; 
import  javax.servlet.http.HttpServletRequest; 
import  org.apache.struts.action.ActionForm; 
import  org.apache.struts.action.ActionMapping; 
import  org.apache.struts.util.LabelValueBean; 


public   class  TestBean  extends  ActionForm { 

// 省略 

   
     private  String stringArray[]  =  
    {  " String 0 " ,  " String 1 " ,  " String 2 " ,  " String 3 " ,  " String 4 "  }; 

     public  String[] getStringArray() { 
         return  ( this .stringArray); 
    } 

     public   void  setStringArray(String stringArray[]) { 
         this .stringArray  =  stringArray; 
    } 

// 省略.. 
   }