请各位高手帮看下这段jsp代码那个i%3==0的那部分代码不是很懂谢谢

<%@ page language="java" pageEncoding="GBK"%>
<%@page import="BookDao.*"%>
<%@page import="entity.*"%>
<%@page import="java.util.*"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<HTML>
<HEAD>
<TITLE>ebooks</TITLE>
<META http-equiv=Content-Type content="text/html; charset=gb2312">
<LINK href="<%=basePath%>images/main.css" type=text/css rel=stylesheet>
</HEAD>
<BODY>
<CENTER>
<TABLE cellSpacing=0 cellPadding=0 width=778 bgColor=#ffffff
background=/store/images/top1bg.jpg border=0>
<TBODY>
<TR>
<TD width=778>&nbsp;</TD>
</TR>
</TBODY>
</TABLE>
<TABLE class=center height=100 cellSpacing=0 cellPadding=0 width=778
bgColor=#ffffff border=0>
<TBODY>
<TR>
<TD align=middle width=150><IMG title="" height=100
src="<%=basePath%>images/logo.jpg" width=100 border=0></TD>
<TD width=58>&nbsp;</TD>
<TD vAlign=top width=110><IMG height=90 src="<%=basePath%>images/top1.jpg"
width=70 border=0></TD>
<TD vAlign=top width=110><IMG height=90 src="<%=basePath%>images/top2.jpg"
width=70 border=0></TD>
<TD vAlign=top width=110><IMG height=90 src="<%=basePath%>images/top3.jpg"
width=70 border=0></TD>
<TD vAlign=top width=110><IMG height=90 src="<%=basePath%>images/top4.jpg"
width=70 border=0></TD>
<TD width=130></TD>
</TR>
</TBODY>
</TABLE><TABLE class=center cellSpacing=0 cellPadding=0 width=778
bgColor=#ffffff border=0>
<TBODY>
<tr>
<TD style="FONT-SIZE: 1px" bgColor=#b0b0b0 colSpan=19 height=1></TD>
</TR>
</TBODY>
</TABLE>
<TABLE cellSpacing=0 cellPadding=0 width=778 bgColor=#ffffff border=0>
<TBODY>
<TR>
<TD style="FONT-SIZE: 1px" bgColor=#dcdcdc height=3></TD>
</TR>
<TR>
<TD align=right background=<%=basePath%>images/bn01.jpg height=120>&nbsp;</TD>
</TR>
</TBODY>
</TABLE><TABLE height=15 cellSpacing=0 cellPadding=0 width=778 border=0>
<TBODY>
<TR>
<TD style="FONT-SIZE: 10px; LINE-HEIGHT: 10px"
background=<%=basePath%>images/bnbg1.gif height=15></TD>
</TR>
</TBODY>
</TABLE>
<TABLE cellSpacing=0 cellPadding=0 width=778 bgColor=#ffffff border=0>
<TBODY>
<TR>
<TD vAlign=top width=168 height=400>
<TABLE class=center height="100%" cellSpacing=0 cellPadding=0
width=168 bgColor=#ffffff background=<%=basePath%>images/leftbg.gif border=0>
<TBODY> <TR>
<TD class=lefttd vAlign=top align=middle><BR>
</TD>
</TR>
</TBODY>
</TABLE>
</TD>
<TD vAlign=top align=middle width=610>
<TABLE cellSpacing=0 cellPadding=0 width="98%"
background=/store/images/top01.gif border=0>
<TBODY>
<TR>
<TD align=left height=25><IMG height=11
src="<%=basePath%>images/icon1.gif" width=31> 图书列表</TD>
</TR>
</TBODY>
</TABLE>
<BR>
<TABLE style="TEXT-ALIGN: center" cellSpacing=0 cellPadding=0
width=590 border=0>
<TBODY>
<!--   显示内容开始  -->
<%TitlesDao titlesBean = new TitlesDao();
     List list=(List)session.getAttribute("list");      // store titles in session for further use
      for(int i=0;i<list.size();i++){
       BookBean currentBook = ( BookBean )list.get(i);
      if(i%3==0){       %>      
       <TR>
       <%
       }
      %>
      <TD>
<TABLE cellSpacing=0 cellPadding=0 width=180
background=/store/images/bg.jpg border=0>
<TBODY>
<TR>
<TD vAlign=bottom height=30>&nbsp;&nbsp; <a href = 
               "displayBook.jsp?isbn=<%= currentBook.getIsbn() %>">&nbsp;&nbsp;&nbsp;&nbsp; <%= subStr(currentBook.getTitle() + ", " +
                   currentBook.getEditionNumber() + "e") %></a></TD>
</TR>
<TR align=middle>
<TD height=120><A href="displayBook.jsp?isbn=<%= currentBook.getIsbn() %>"><IMG
height=110 src="<%=currentBook.getImageFile() %>" width=90
border=0></A></TD>
</TR>
</TBODY>
</TABLE>
<BR>
</TD>
      
      <%
       if(i%3==2){
       %>
      
       </TR>
       <%
       }
      }
  %>
<!--   显示内容结束  -->
</TBODY>
</TABLE>
<BR>
</TD>
</TR>
</TBODY>
</TABLE>
<TABLE class=center cellSpacing=0 cellPadding=0 width=778
bgColor=#ffffff border=0>
<TBODY>
<TR>
<TD align=middle background=<%=basePath%>images/bk.gif height=50></TD>
</TR>
</TBODY>
</TABLE></CENTER>
</BODY>
</HTML>
<%! public String subStr(String str){
if(str==null || "".equals(str))
return "";
if(str.length()>20)
return str.substring(0,20)+"...";
else
return str;
}
 %>

解决方案 »

  1.   

    每行三个，之后换行
          for(int i=0;i <list.size();i++){ 
          BookBean currentBook = ( BookBean )list.get(i); 
        if(i%3==0){      %>      
          <TR>       <% 
          } 
          %> 
          <TD> 
    <TABLE cellSpacing=0 cellPadding=0 width=180 
    background=/store/images/bg.jpg border=0> 
    <TBODY> 
    <TR> 
    <TD vAlign=bottom height=30>&nbsp;&nbsp; <a href = 
                  "displayBook.jsp?isbn= <%= currentBook.getIsbn() %>">&nbsp;&nbsp;&nbsp;&nbsp; <%= subStr(currentBook.getTitle() + ", " + 
                      currentBook.getEditionNumber() + "e") %> </a> </TD> 
    </TR> 
    <TR align=middle> 
    <TD height=120> <A href="displayBook.jsp?isbn= <%= currentBook.getIsbn() %>"> <IMG 
    height=110 src=" <%=currentBook.getImageFile() %>" width=90 
    border=0> </A> </TD> 
    </TR> 
    </TBODY> 
    </TABLE> 
    <BR> 
    </TD> 
          
          <% 
          if(i%3==2){       %> 
          
          </TR>       <% 
          } 
          } 
      %> 
    两处红色标出的就是控制每行信息个数的，要一起分析
      

  2.   

    if(i%3==0)  如果i是3的倍数，就执行if语句块