struts custom tag

時間 2019-11-25

標籤 struts custom tag 欄目 Struts 简体版

原文原文鏈接

一、<%@ taglib uri="/struts-layout-tags" prefix="layout"%>中struts-layout-tags類javascript

<tag>
  <name>yield</name>
    <tag-class>com.fangdo.core.view.YieldTag</tag-class>
    <body-content>JSP</body-content>
    <description><![CDATA[Include a servlet's output (result of servlet or a JSP page)]]></description>
    <attribute>
      <name>id</name>
      <required>false</required>
      <rtexprvalue>true</rtexprvalue>
      <description><![CDATA[id for referencing element. For UI and form tags it will be used as HTML id attribute]]></description>
    </attribute>
    <attribute>
      <name>value</name>
      <required>false</required>
      <rtexprvalue>true</rtexprvalue>
      <description><![CDATA[The jsp/servlet output to include]]></description>
    </attribute>
  </tag>

二、yieldTag類css

繼承ComponentTagSupport類是爲了得到JSP頁面中用戶自定義的標籤中設置的屬性值，幷包裝成Component對象。

Component:
繼承Component類是爲了從Struts2中的ValueStack中得到相對應的值。

public class YieldTag extends ComponentTagSupport {

	protected String value;
	
	public Component getBean(ValueStack stack, HttpServletRequest req, HttpServletResponse res) {
		return new Yield(stack, req, res);
	}
//protected void populateParams()此方法是用來將JSP頁面傳來的屬性值賦給基本類。這裏是繼承來的，因此首先調用super的相應方法。 	protected void populateParams() {
		super.populateParams();
		((Yield) component).setValue(value);
	}

	public void setValue(String value) {
		this.value = value;
	}
}

三、Yield類

重寫start，end等方法便可。html

public class Yield extends Component {
	
	private static boolean encodingDefined = true;
	private static String encoding;    
    private static String defaultEncoding;
    
	private String value;
	private HttpServletRequest req;
	private HttpServletResponse res;
	
	public Yield(ValueStack stack,HttpServletRequest req,HttpServletResponse res){
		super(stack);
		this.req = req;
		this.res = res;
	}

    @Inject(StrutsConstants.STRUTS_I18N_ENCODING)
    public static void setDefaultEncoding(String encoding) {
        defaultEncoding = encoding;
    }
    
    private static String getEncoding() {
        if (encodingDefined) {
            try {
                encoding = defaultEncoding;
            } catch (IllegalArgumentException e) {
                encoding = System.getProperty("file.encoding");
                encodingDefined = false;
            }
        }

        return encoding;
    }
    
	@Override
	public boolean end(Writer writer, String body) {
		
		String name = StringUtils.isBlank(value) ? "content_for_layout" : "content_for_" + value;
		FastByteArrayOutputStream content = (FastByteArrayOutputStream) req.getAttribute(name);
		if(content !=null){
			String encoding = getEncoding();
			try{	
			if (encoding != null) {
				content.writeTo(writer, encoding);
	        } else {
	        	content.writeTo(writer,null);
	        }
			} catch(IOException e) {
				LogFactory.getLog(getClass()).warn("Exception thrown during ", e);
			}
		}
		return super.end(writer, body);
	}

	public void setValue(String value) {
		this.value = value;
	}	
}

四、jsp中java

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-layout-tags" prefix="layout"%>
<% String rootPath = request.getContextPath(); %>
<!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><layout:yield value="title"/></title>
<script type="text/javascript" src="<%= rootPath %>/js/jquery.js"></script>
。。。


<link rel="stylesheet" type="text/css" href="<%= rootPath %>/css/easyui/icon.css"/>
<link rel="stylesheet" type="text/css" href="<%= rootPath %>/css/easyui/default/easyui.css">
<script type="text/javascript" src="<%= rootPath %>/js/jquery.easyui.min.js"></script>

</head>
<body class="easyui-layout">

	<div region="north" border="false"  style="height:60px;background:#B3DFDA;">
		<jsp:include page="../layout/top.jsp"></jsp:include>
	</div>

	<div region="west" split="true" title="導航" style="width:200px;padding:10px;">
		<jsp:include page="../user/_left_menu.jsp"></jsp:include>
	</div>

	

	<div region="south" border="false" style="height:50px;background:#A9FACD;padding:10px;">south region</div>

	<div region="center" title="Main Title">
	<div id="page">
		<jsp:include page="../web/_message.jsp"></jsp:include>
		<div class="workspace">
			<layout:yield />
		</div>
	</div>>
	</div>
</body>

</html>

相關標籤/搜索

getcomponent+sendmessage+tag

struts+spring+hibernate

myeclipse+struts+hibernate+mysql

Struts

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