Customize tag lib 1 (freemarker)

最新推荐文章于 2022-07-01 11:00:22 发布

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#freemarker #string #struts #jsp #encoding #library

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本文介绍如何通过六个步骤定制Struts2标签库，包括定义组件、标签、Freemarker模板、配置文件等，并展示了使用自定义标签的具体示例。

Want to customize a tag lib, we need to do follow the steps:

1. Define the component (UIBean)

package com.stefli.core.component.taglib; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.struts2.components.UIBean; import org.apache.struts2.views.annotations.StrutsTag; import org.apache.struts2.views.annotations.StrutsTagAttribute; import com.opensymphony.xwork2.util.ValueStack; @StrutsTag(name = "hello", tldTagClass = "com.stefli.core.component.taglib.HelloWorldTag", description = "HelloWorld TagLib") public class HelloWorld extends UIBean { final public static String TEMPLATE = "helloworld"; protected String helloworld; public HelloWorld(ValueStack stack, HttpServletRequest request, HttpServletResponse response) { super(stack, request, response); } @Override protected String getDefaultTemplate() { return TEMPLATE; } @StrutsTagAttribute(description = "Echo a helloworld", type = "String") public void setHelloworld(String helloworld) { this.helloworld = helloworld; } @Override protected void evaluateExtraParams() { super.evaluateExtraParams(); if (helloworld != null) { addParameter("helloworld", findValue(helloworld, String.class)); } } }

2. Define the tag

package com.stefli.core.component.taglib; import org.apache.struts2.views.jsp.ui.AbstractUITag; import org.apache.struts2.components.Component; import com.opensymphony.xwork2.util.ValueStack; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class HelloWorldTag extends AbstractUITag { private static final long serialVersionUID = 6344363772863485885L; protected String helloworld; protected void populateParams() { super.populateParams(); HelloWorld hello = (HelloWorld) component; hello.setHelloworld(helloworld); } @Override public Component getBean(ValueStack stack, HttpServletRequest request, HttpServletResponse response) { return new HelloWorld(stack, request, response); } public void setHelloworld(String helloworld) { this.helloworld = helloworld; } }

3. Define freemarker template, which should be added to "WEB-INF/classes/template/simple" folder.

We also can change the folder to template/xhtml, which is related with struts theme.

Say hello to: <span>${parameters.helloworld}</span><#rt/>

4. Define the tag configuration file, which should be added to "WEB-INF/tld/tms-tags.tld"

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd"> <taglib> <tlib-version>1.1.0</tlib-version> <jsp-version>1.2</jsp-version> <short-name>t</short-name> <uri>/tms-tags</uri> <display-name>"TMS Tags"</display-name> <description></description> </attribute> </tag> </taglib>

5. Configure the web.xml to load the tag lib when server is up.

<jsp-config> <taglib> <taglib-uri>/WEB-INF/tld/tms-tags.tld</taglib-uri> <taglib-location>/tms</taglib-location> </taglib> </jsp-config>

6. Use the tag lib in jsp

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <%@ taglib prefix="s" uri="/struts-tags"%> <%@ taglib prefix="tms" uri="/tms-tags"%> <!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>HelloWorld TagLib</title> </head> <body> <div> <tms:hello helloworld="Stefli" /> </div> </body> </html>

Ok, you'll see the result when visit the jsp.

Say hello to: Stefli