学习笔记---使用prototype.js扩展struts标签实现xmlhttprequest

最新推荐文章于 2022-08-01 21:00:38 发布

原创最新推荐文章于 2022-08-01 21:00:38 发布 · 1.2k 阅读

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文章标签：

#struts #xmlhttprequest #扩展 #action #asynchronous #getter

本文介绍如何将Struts框架与Ajax技术相结合，通过修改Struts的表单标签实现Ajax功能，具体展示了如何创建带有Ajax功能的表单，并配置Struts及前端页面使用方法。

要点

1 prototypes.js很好的封装了javascript的oo和客户端的ui效果

2 struts还很常用,能混口饭吃

3 rails对web2.0的标签有

1 link_to_remote 2 form_remote_tag 3 observe_field 4 periodiccally_call_remote

都是对prototypes.js的服务端封装,和jsp中taglib一样

4 prototypes.js中的Ajax.Updateter把xmlhttprequest的整个回掉流程封装得很好了

5 改写一个struts的form标签,让他具有ajax功能

5.1 taglib处理类

package com.xxxx.web.taglib;

import javax.servlet.http.HttpServletResponse;

import org.apache.struts.taglib.TagUtils;
import org.apache.struts.taglib.html.FormTag;

/**

* <p>xhr请求表单<br>

* <p>

* @author powerbear

* @since Dec 14, 2006 6:07:06 PM

public class FormRemoteTag extends FormTag // 继承struts的form标签

{

private String update; //需要更新的页面元素id

private String url;//请求的url

private String loading;//请求过程中需要执行的js事件

private String complete;//完成请求后执行的js事件

/**

* Renders Ajax url attribute 获取action的url

protected String renderUrl()

{

HttpServletResponse response = (HttpServletResponse) this.pageContext

.getResponse();

return response.encodeURL(TagUtils.getInstance().getActionMappingURL(

this.action, this.pageContext));

}

/**

* Randers prototype Ajax.Updater 渲染出客户端的Ajax.Updater事件

* @return

protected String renderAjaxElement()

{

if (url == null || url.length() == 0)

{

this.url = this.renderUrl();

}

StringBuffer results = new StringBuffer("new Ajax.Updater(");

results.append("'" + this.update + "',");

results.append("'" + this.url + "',");

results.append("{asynchronous:true, evalScripts:true,");

results.append("onComplete:function(request){" + this.complete + "},");

results.append("onLoading:function(request){" + this.loading + "}, ");

results.append("parameters:Form.serialize(this)});");

results.append("return false;"");

return results.toString();

}

/**

* Return the onSubmit event script. 重写FormTag的onSubmit属性的getter,把protorypes事件加进去

public String getOnsubmit()

{

return (renderAjaxElement());

}

//属性的getter和setter对

}

5.2 taglib配置

<?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 xmlns=" http://java.sun.com/JSP/TagLibraryDescriptor">
<tlib-version>1.1</tlib-version>
<jsp-version>1.2</jsp-version>
<short-name>XXXX Tag Library</short-name>
<uri>http://XXXX.com/tags/</uri>
<description>XXXX Tag Library</description>

< tag >

< name > form_remote_tag </ name >

< tag-class >

com.xxxx.web.taglib.FormRemoteTag

</ tag-class >

< description > xml_httm_request form </ description >

< attribute >

< name > action </ name >

< required > true </ required >