JSP 自定义标签库兑现步骤

JSP 自定义标签库实现步骤

java类：

package com.Aaron.test;

import java.util.Properties;

import javax.servlet.http.HttpSession;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.TagSupport;

public class MessageTag extends TagSupport {
private String key;

public MessageTag(){

}
@Override
public int doEndTag() throws JspException {
  try {
   Properties ps = (Properties)pageContext.getAttribute("ps",pageContext.APPLICATION_SCOPE);
   Properties ps_zh = (Properties)pageContext.getAttribute("ps_zh",pageContext.APPLICATION_SCOPE);
   HttpSession session = pageContext.getSession();
   String language = (String)session.getAttribute("language");
   String message = null;
   if(language != null && language.equals("Chinese")){
    message = ps_zh.getProperty(key);
   }else{
    message = ps.getProperty(key);
   }
   pageContext.getOut().print(message);
  } catch (Exception e) {
   throw new JspTagException(e.getMessage());
  }
  return SKIP_BODY;
}
@Override
public void release() {
  super.release();
}
public String getKey() {
  return key;
}

public void setKey(String key) {
this.key = key;
}

}

**************************************************

tld标签：

<?xml version="1.0" encoding="UTF-8"?>

<taglib>
    <tlibversion>1.0</tlibversion>
    <jspversion>1.1</jspversion>
    <shortname>mytaglib</shortname>
    <uri>/mytaglib</uri>
    <tag>
        <name> message</name>
        <tagclass>com.Aaron.test.MessageTag </tagclass>
        <bodycontent>empty </bodycontent>
        <info>produce message by key</info>
        <attribute>
            <name>key</name>
            <required>true</required>
        </attribute>
    </tag>
</taglib>

******************************************************

web.xml:

<taglib>
<taglib-uri>/mytaglib</taglib-uri>
<taglib-location>/WEB-INF/mytaglib.tld</taglib-location>
</taglib>

***************************************************

jsp 页面：

<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="ISO-8859-1" %>
< %@taglib uri="/mytaglib" prefix="msg" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd ">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title><msg:message key="hello.hello"/></ title>
    </head>
    <body>
        <%
         String language = request.getParameter("language");
         language = language == null ? "English" : language;
         session.setAttribute("language",language);
   %>
        <msg:message key="login.user"/>:<input type="text"/>
        <br>
        <msg:message key="login.password"/>:<input type="password"/>
        <br>
        <msg:message key="login.submit"/>:<input type="submit"/>
    </body>
</html>

JSP 自定义标签库兑现步骤

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