jsp通过自定义标签库实现数据列表显示的方法
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2022-05-28 17:53:59
本文实例讲述了jsp通过自定义标签库实现数据列表显示的方法。分享给大家供大家参考，具体如下：
1. 定义标签库类 userlisttag.java
packag...
本文实例讲述了jsp通过自定义标签库实现数据列表显示的方法。分享给大家供大家参考，具体如下：
1. 定义标签库类 userlisttag.java
package com.yanek.cms.tag;
import java.io.ioexception;
import java.util.arraylist;
import java.util.iterator;
import java.util.list;
import javax.servlet.jsp.jspexception;
import javax.servlet.jsp.tagext.bodytagsupport;
import com.yanek.cms.vo.userinfo;
public class userlisttag extends bodytagsupport {
private string name;// 一个属性名
private iterator it;// 要迭代的对象
private int cateid; // 用户类别id
@override
public int doendtag() throws jspexception {
try {
if (bodycontent != null) {
bodycontent.writeout(bodycontent.getenclosingwriter());
}
} catch (ioexception e) {
e.printstacktrace();
}
return eval_page;
}
@override
public int dostarttag() throws jspexception {
//这里根据用户类型,构造不同的列表数据,实现可以根据数据库获取
list<userinfo> users = new arraylist<userinfo>();
if (cateid == 1) {
users.add(new userinfo("张三", 20, "zhangsan@163.com"));
users.add(new userinfo("李四", 30, "lisi@sina.com"));
} else {
users.add(new userinfo("王五", 33, "wangwu@qq.com"));
users.add(new userinfo("赵六", 33, "zhaoliu@qq.com"));
}
it = users.iterator();
if (it == null) {
return skip_body;
} else {
return continuenext();
}
}
private int continuenext() {
if (it.hasnext()) {
pagecontext.setattribute(name, it.next(), pagecontext.page_scope);
return eval_body_tag;
} else {
return skip_body;
}
}
@override
public int doafterbody() {
return continuenext();
}
public string getname() {
return name;
}
public void setname(string name) {
this.name = name;
}
public int getcateid() {
return cateid;
}
public void setcateid(int cateid) {
this.cateid = cateid;
}
}
2. 在web-inf目录下 新建标签库描述文件my_cms_tag.tld：
my_cms_tag.tld
<?xml version="1.0" encoding="utf-8"?>
<!doctype taglib public "-//sun microsystems, inc.//dtd jsp tag library 1.1//en" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd">
<taglib>
<tlibversion>1.0</tlibversion>
<jspversion>1.0</jspversion>
<shortname>cms</shortname>
<uri>http://www.58tech.cn/mystruts/tags-cms</uri>
<!-- userlisttag start -->
<tag>
<name>userlisttag</name>
<tag-class>com.yanek.cms.tag.userlisttag</tag-class>
<body-content>jsp</body-content>
<variable>
<!--<name-given>user_info</name-given>-->
<name-from-attribute>name</name-from-attribute>
<variable-class>com.yanek.cms.vo.userinfo</variable-class>
<declare>true</declare>
<scope>nested</scope>
</variable>
<attribute>
<name>name</name>
<required>true</required>
</attribute>
<attribute>
<name>cateid</name>
<required>true</required>
</attribute>
</tag>
<!-- userlisttag end -->
</taglib>
3. web.xml配置
<?xml version="1.0" encoding="utf-8"?> <web-app 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 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> <taglib> <taglib-uri>/tags/my-cms</taglib-uri> <taglib-location>/web-inf/my_cms_tag.tld</taglib-location> </taglib> </web-app>
4. jsp调用
<%@ page language="java" import="java.util.*,com.yanek.cms.vo.*" pageencoding="utf-8"%>
<%@ taglib uri="/tags/my-cms" prefix="mytag" %>
<%
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 'test.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<table width='500px' border='1' align='center'>
<tr>
<td width='20%'>username</td>
<td width='20%'>age</td>
<td>email</td>
</tr>
<mytag:userlisttag name="user_info1" cateid="1">
<tr>
<td><%=user_info1.getusername() %></td>
<td><%=user_info1.getage() %></td>
<td><%=user_info1.getemail() %>
</td>
</tr>
</mytag:userlisttag>
</table>
<hr>
<table width='500px' border='1' align='center'>
<tr>
<td width='20%'>username</td>
<td width='20%'>age</td>
<td>email</td>
</tr>
<mytag:userlisttag name="user_info2" cateid="2">
<tr>
<td><%=user_info2.getusername() %></td>
<td><%=user_info2.getage() %></td>
<td><%=user_info2.getemail() %>
</td>
</tr>
</mytag:userlisttag>
</table>
</body>
</html>
实体类定义
package com.yanek.cms.vo;
public class userinfo {
private int age;
private string username;
private string email;
public int getage() {
return age;
}
public void setage(int age) {
this.age = age;
}
public string getusername() {
return username;
}
public void setusername(string username) {
this.username = username;
}
public string getemail() {
return email;
}
public void setemail(string email) {
this.email = email;
}
public userinfo(string username,int age, string email) {
super();
this.age = age;
this.username = username;
this.email = email;
}
public userinfo() {
}
}
运行效果如下图 （url输入：http://127.0.0.1:8080/testcms/page/userlist.jsp）
完整实例代码代码点击此处。
希望本文所述对大家android程序设计有所帮助。