Understand the incrude in JSP: include-file instruction test

xiaoxiao2021-03-06  113

First example:

INCLUDE-FILE-TEST-1.Jsp:

<% @ page contenttype = "text / html; charset = GBK"%>

<%! String dec_str = "dec_str";%>

<% = DEC_STR%>

<% @ include file = "include-file-test-2.jsp"%>

<% = DEC_STR%>

INCLUDE-file-test-2.jsp:

<% @ page contenttype = "text / html; charset = GBK"%>

<%

DEC_STR = "SCR_STR"; // Eclipse shows an error.

%>

result:

DEC_STR

SCR_STR

Conclusion: The example variable (or part variable) defined in File1, file2 can be referenced and changed. But directly accessing file2 will be wrong.

Second example:

INCLUDE-FILE-TEST-1.Jsp:

<% @ page contenttype = "text / html; charset = GBK"%>

<% SCR_STR = "Hello" SCR_STR;%>

<% @ include file = "include-file-test-2.jsp"%>

<% = SCR_STR%>

<% Temp = "Hello" TEMP;%>

<% = Temp%>

INCLUDE-file-test-2.jsp:

<% @ page contenttype = "text / html; charset = GBK"%>

<%! String Scr_Str = "SCR_STR";%>

<% String Temp = "TEMP";%>

View File1 corresponding to servlet:

Package org.apache.jsp.jsp_002dsyntax_002dtest;

Import ...;

PUBLIC FINAL CLASS INCLUDE_002DFILE_002DTEST_002D1_JSP ... {

String SCR_STR = "SCR_STR";

Private static java.util.vector _jspx_dependants;

STATIC {

_jspx_dependants = new java.util.vector (1);

_jspx_dependants.add ("/ jsp-syntax-test / include-file-test-2.jsp");

}

Public java.util.list getDependants () {

Return_Jspx_Dependants;

}

Public void _jspservice (httpservletRequest Request, httpservletResponse response)

Throws java.io.ioException, servletexception {

......

Try {

......

Response.setContentType ("text / html; charSet = GBK"); ......

Scr_Str = "Hello" SCR_STR;

String Temp = "TEMP";

......

OUT.PRINT (SCR_STR);

Temp = "Hello" TEMP;

......

Out.print (TEMP);

} catch (throwable t) {

......

} finally {

......

}

}

}

result:

Hello SCR_STR

Hello Temp

Conclusion: The example variables defined in File2, file1 can be referenced and changed before <% @ include file = ""%> command (or later).

The partial variables defined in File2 must be referenced and changed after the <% @ include file = ""%> command.

Third example:

INCLUDE-FILE-TEST-1.Jsp:

<% @ page contenttype = "text / html; charset = GBK"%>

<%!

String str1 = "str1";

%>

<%

String str4 = str1 str2 str3;

%>

<% @ include file = "include-file-test-2.jsp"%>

<% = STR4%>

INCLUDE-file-test-2.jsp:

<% @ page contenttype = "text / html; charset = GBK"%>

<%!

String str2 = "str2";

String str3 = STR1 STR2;

%>

File1 corresponds to servlet:

Package org.apache.jsp.jsp_002dsyntax_002dtest;

IMPORT ...

PUBLIC FINAL CLASS INCLUDE_002DFILE_002DTEST_002D1_JSP ... {

String str1 = "str1";

String str2 = "str2";

String str3 = STR1 STR2;

......

Public void _jspservice (httpservletRequest Request, httpservletResponse response)

Throws java.io.ioException, servletexception {

......

Try {

......

Response.setContentType ("text / html; charset = GBK");

......

String str4 = str1 str2 str3;

......

Out.print (STR4);

} catch (throwable t) {

......

}

result:

STR1 STR2 STR1 STR2

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