JSP through the custom tag library to implement the data list display method _jsp programming

This article is an example of a JSP through a custom tag library to achieve a list of data display methods. Share to everyone for your reference, specific as follows:

1. Define tag Library class 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;//a property name private iterator it;//to iterate objects private in T Cateid; User class ID @Override public int doendtag () throws Jspexception {try {if (bodycontent!= null) {Bodycontent.writeo
  UT (Bodycontent.getenclosingwriter ());
 } catch (IOException e) {e.printstacktrace ();
 return eval_page; @Override public int doStartTag () throws Jspexception {//here, according to the user type, constructs different list data that can be obtained list<userinfo> users based on the database
 = new Arraylist<userinfo> ();
  if (Cateid = = 1) {Users.add (New UserInfo ("John", "Zhangsan@163.com"));
 Users.add (New UserInfo ("Dick", "Lisi@sina.com"));
  else {users.add (new UserInfo ("Harry", "Wangwu@qq.com")); Users.add (New UserInfo("Zhao Liu", "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;
 The public void Setcateid (int cateid) {This.cateid = Cateid;

 }
}

2. Create a new Tag library description file in the Web-inf directory 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> <r Equired>true</required> </attribute> <attribute> <name>cateid</name> <required>tru

 E</required> </attribute> </tag> <!--userlisttag end--> </taglib>

3. Web.xml Configuration

<?xml version= "1.0" encoding= "UTF-8"?> <web-app version=
"2.5" xmlns= "http://java.sun.com/xml/ns/" 
 Java ee "
 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 Call

<%@ 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" >  

Entity class definition

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 () {
 }
}

The operation effect is as follows (URL input: http://127.0.0.1:8080/TestCMS/page/userlist.jsp)

Full instance code code click here to download the site.

I hope this article will help you with the Android program.