Understanding include in JSP (ii): Jsp-include test

Include|js First Example:

File1:

<%
String str = "AAAAA";
%>
<jsp:include page= "jsp-include-slave.jsp"/>

<%=str%>

File2:

<%
str = str + "BBBBB";
%>

Results:

Error accessing File1, indicating that variable STR cannot be resolved in file2.

Analysis:

When requesting File1, Tomcat first converts two JSP files to servlet (. java) files. You then attempt to compile both into. class files, at which point File1 compiles normally, and file2 does not compile.

Conclusion:

Unlike the Include-file directive, which merges two files into a servlet file for compilation and execution, Jsp-include requires two files to be relatively independent and complete.





A second example:

File1:

<%@ page contenttype= "TEXT/HTML;CHARSET=GBK"%>
<%
Request.setattribute ("str", "AAAAAAAAAAAAAAAA");
%>
<jsp:include page= "jsp-include-slave.jsp"/>


File2:

<%@ page contenttype= "TEXT/HTML;CHARSET=GBK"%>
<%
String str = (string) request.getattribute ("str");
Out.println (str);
%>

Results:

Aaaaaaaaaaaaaaaa

Analysis:

Because two pages are relatively independent, you can pass requests in between. That is, when a request is file1, File1 automatically requests file2.

Conclusion:

Using Jsp-include's two pages is a request relationship, not a relationship. This is different from include-file.





A third example:

File1:

<%@ page contenttype= "TEXT/HTML;CHARSET=GBK"%>
<%
Request.setattribute ("str", "AAAAAAAAAAAAAAAA");
%>
<jsp:include page= "jsp-include-slave.jsp"/>
<br>
<%
String str = (string) request.getattribute ("str");
Out.println (str);
%>


File2:

<%@ page contenttype= "TEXT/HTML;CHARSET=GBK"%>
<%
String str = (string) request.getattribute ("str");
Request.setattribute ("str", str+ "bbbbbbbbbbbbbbb");
%>

Results:

aaaaaaaaaaaaaaaabbbbbbbbbbbbbbb

Conclusion:

The two-page request relationship is bidirectional.