在實(shí)際處理的頁(yè)面中,往往在一個(gè)頁(yè)面中有多個(gè)觸發(fā)的動(dòng)作,而Struts的ActionForm中只能指定一個(gè)Action,是一種粗粒度的實(shí)現(xiàn)(JSF中有更好的解決方案),computeURL( )可以提供一種變通的解決方法.
computeURL( )是在
org.apache.struts.util.RequestUtils(Struts Ver1.1)與org.apache.struts.taglib.TagUtils(Struts Ver1.2)類中的一個(gè)函數(shù),用來(lái)解析基于Forward,Action,鏈接,頁(yè)面參數(shù)的URL可以用來(lái)動(dòng)態(tài)改變頁(yè)面中Form對(duì)應(yīng)的Action.Ver1.1中有以下兩種:
1.
computeURL(javax.servlet.jsp.PageContext pageContext, java.lang.String forward, java.lang.String href, java.lang.String page, java.util.Map params, java.lang.String anchor, boolean redirect)
2.computeURL(javax.servlet.jsp.PageContext pageContext, java.lang.String forward, java.lang.String href, java.lang.String page, java.lang.String action, java.util.Map params, java.lang.String anchor, boolean redirect)
其中第一個(gè)是 Deprecated.第二個(gè)在新版本中得以保留,另外還提供了另外一種重載:
computeURL(javax.servlet.jsp.PageContext pageContext, java.lang.String forward, java.lang.String href, java.lang.String page, java.lang.String action, java.lang.String module, java.util.Map params, java.lang.String anchor, boolean redirect, boolean encodeSeparator) 參數(shù)說(shuō)明如下:
Parameters:
pageContext - PageContext for the tag making this call
forward - Logical forward name for which to look up the context-relative URI (if specified)
href - URL to be utilized unmodified (if specified)
page - Module-relative page for which a URL should be created (if specified)
action - Logical action name for which to look up the context-relative URI (if specified)
params - Map of parameters to be dynamically included (if any)
anchor - Anchor to be dynamically included (if any)
redirect - Is this URL for a response.sendRedirect(
下面介紹一下詳細(xì)的使用方法:
1.在JSP頁(yè)面中導(dǎo)入對(duì)應(yīng)的包:
<%@ page import= "org.apache.struts.util.RequestUtils"%>
或
<%@ page import= "org.apache.struts.taglib.TagUtils"%>
2.創(chuàng)建一個(gè)JAVASCRIPT函數(shù):
<script language="JavaScript" type="text/javascript">
function search() {
<%String searchUrl = RequestUtils.computeURL(
pageContext,
null,
null,
"/Search.do",
null,
null,
null,
false);
%>
document.form1.action = "<%=searchUrl%>";
document.form1.submit();
}
</script>
3.在JSP頁(yè)面中給對(duì)應(yīng)的表單指定ID以便上面的函數(shù)進(jìn)行確定提交的是哪個(gè)FORM(如果一個(gè)頁(yè)面在存在多個(gè)FORM的話):
<html:form styleId="form1" action="/aotherSearch">
.........
</html:form>
4.在需要觸發(fā)提交動(dòng)作的地方,調(diào)用2中的JAVASCRIPT函數(shù):
<html:button property="searchInfo" value="檢索" onclick="search()" style="width:100px" />
對(duì)應(yīng)的ACTION與FORM在配置文件中定義.這樣,就可以動(dòng)態(tài)更改FORM的ACTION實(shí)現(xiàn)一個(gè)FORM對(duì)應(yīng)多個(gè)ACTION了.