Including JSP page into another JSP page, how to avoid multiple HEAD / BODY sections?_问答_开发者

Including JSP page into another JSP page, how to avoid multiple HEAD / BODY sections?

开发者 https://www.devze.com 2022-12-13 16:05 出处：网络

I would like to include a JSP page into another 开发者_开发百科JSP page. Let\'s say that I have master.jsp that is including slave.jsp.

I would like to include a JSP page into another 开发者_开发百科JSP page. Let's say that I have master.jsp that is including slave.jsp.

As slave.jsp has its own <head> section for dealing with JavaScript and CSS, is there a way or maybe another method to merge the masterand slave HEADs section into a single one? Also the same should done for the BODYs section.

I have been using sitemesh recently but I think is quite impractical to setup a template for each page.

I went for this solution by passing a parameter when including the page.

in master.jsp

<head>
  blablabla
  <c:import url="slave.jsp">
    <c:param name="sectionName" value="HEAD" />
  </c:import>
</head>
<body>
  blablabla
  <c:import url="slave.jsp">
  </c:import>
</body>

and then in slave.jsp the parameter is read and the custom part of the page is rendered.

<c:choose>
  <c:when test="${param.sectionName == 'HEAD'}">
     head section here [without the <HEAD> tags !]
  </c:when>
  <c:otherwise>
     body section here [without the <BODY> tags !]
  </c:otherwise>
</c:choose>

not too nice to see but working. In this way I am able to remove the duplication of HEAD and BODY parts.

You cannot and should not merge two <html> documents in each other. This would produce invalid output. Better include CSS/JS conditionally with help of JSTL c:if or c:choose tags.

Basic example:

<head>
    <script type="text/javascript" src="global.js"></script>
    <c:if test="${isAdminPage}">
        <script type="text/javascript" src="admin.js"></script>
    </c:if>
</head>

Outside of sitemesh, you're pretty much out of luck. However I would reconsider your design if you think that the setup per page is impractical. How many pages will your app have?

You could also extend the conditional option, and make a meta.jsp (for example), which contains a Map for each of the head elements - meta tags, css hrefs, script hrefs, and use the name of the jsp as a key in that Map. Then you call request.getRequestURI(), and show whatever you have put in the map under that key. Not a very beautiful solution, but working.