jsp开发迭代标签一
第一步:编写一个标签处理器类
public class ForeachTag1 extends SimpleTagSupport {
//用来作为关键字存放值
private String var;
private Object items;
public void setVar(String var) {
this.var = var;
}
public void setItems(Object items) {
this.items = items;
}
public void doTag() throws JspException, IOException {
List list=(List)items;
Iterator iterator=list.iterator();
while(iterator.hasNext())
{
Object obj=iterator.next();
this.getJspContext().setAttribute(var, obj);
this.getJspBody().invoke(null);
}
}
}
第二步:WEB-INF 目录下编写一个*.tld标签描述文件
<?xml version="1.0" encoding="UTF-8" ?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
version="2.0">
<description>A tag library exercising SimpleTag handlers.</description>
<tlib-version>1.0</tlib-version>
<short-name>SimpleTagLibrary</short-name>
<uri>http://www.liyong.foreach1tag</uri>
<tag>
<name>foreach1</name>
<tag-class>com.liyong.foreach.ForeachTag1</tag-class>
<body-content>scriptless</body-content>
<attribute>
<name>items</name>
<required>true</required>
<rtexprvalue>true</rtexprvalue>
</attribute>
<attribute>
<name>var</name>
<required>true</required>
<rtexprvalue>false</rtexprvalue>
</attribute>
</tag>
<tag>
</taglib>
第三步:编写jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="http://www.liyong.foreach1tag" prefix="foreach"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'foreach1.jsp' starting page</title>
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body> <br>
<%
List list=new ArrayList();
list.add("aaa");
list.add("bbb");
list.add("ccc");
list.add("ddd");
request.setAttribute("list",list);
%>
<foreach:foreach1 var="str" items="${list}" >
${str }
</foreach:foreach1>
</body>
</html>
第四步:测试...