实现 jstl标签foreach 功能
jsp 页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ include file="/includes/ctx.jsp" %>
<%@ taglib uri="/RemoveListItems" prefix="z"%>
<!DOCTYPE html >
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>角色管理</title>
</head>
<body>
<z:for items="${rolelist}" var="z">
<p>${z.rolename}</p>
</z:for>
</body>
</html>
WEB-INF 目录下创建tld 文件
<?xml version="1.0" encoding="UTF-8"?> <taglib version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee"> <tlibversion>1.0</tlibversion> <jspversion>1.1</jspversion> <shortname>eRedLab JSPTag Library</shortname> <uri>/RemoveListItems</uri> <info>自定义标签</info> <tag> <name>for</name> <tagclass>com.oa.tag.Repeater</tagclass> <bodycontent>scriptless</bodycontent> <info></info> <attribute> <name>items</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>var</name> <required>true</required> <rtexprvalue>true</rtexprvalue> </attribute> <attribute> <name>index</name> <required>false</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>
java 类代码
import java.util.List;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;
public class Repeater extends TagSupport {
/**
*
*/
private static final long serialVersionUID = 4086401651029717288L;
private List<?> items;
private String var;
private String index;
private int i;
@Override
public int doStartTag() throws JspException {
if (items == null || items.size() == 0){
return SKIP_BODY;
}
if(index==null)index = "";
i = 0;
if(i<items.size()){
pageContext.setAttribute(var, items.get(i));
pageContext.setAttribute(index, i);
}
return EVAL_BODY_INCLUDE;
}
@Override
public int doAfterBody() throws JspException {
i++;
if(i < items.size()){
pageContext.setAttribute(var, items.get(i));
pageContext.setAttribute(index, i);
return EVAL_BODY_AGAIN;
}
return SKIP_BODY;
}
@Override
public int doEndTag() throws JspException {
return EVAL_PAGE;
}
public void setItems(List<?> items) {
this.items = items;
}
public void setVar(String var) {
this.var = var;
}
public void setIndex(String index){
this.index = index;
}
}
