<%@include%>和<jsp:include>的区别，发现了一些东西的。

<%@include%>：页面请求之前预编译，所有代码包含进来之后，一起进行处理，把所有代码合在一起，编译成一个servlet

<jsp:include>：所有代码分别处理，在页面被请求的时候才编译，被编译成多个servlet，页面语法相对独立，处理完成之后再将代码的显示结果（处理结果）组合进来。

JSP中的两种包含页面的方法
第一种：include指令：当JSP转换成Servlet时引入指定文件

<%@ pagecontentType="text/html;charset=GB2312" language="java"errorPage=""%>

<%@ include file="head.jsp"%>
<%@ include file="body.jsp"%>
<%@ include file="tail.jsp"%>
第二种：<jsp:include>动作元素：当JSP页面被请求时引入指定文件
<%@ page contentType="text/html; charset=GB2312"language="java" errorPage=""%>
<jsp:include page="head.jsp"/>
<jsp:include page="body.jsp"/>
<jsp:include page="tail.jsp"/>
第二种方法可以很方便的用<jsp:param>来向所包含页传递参数，方法如下：
<%@ page contentType="text/html; charset=GB2312"language="java" errorPage=""%>
<jsp:include page="head.jsp"/>
<jsp:includepage="body.jsp">
<jsp:param name="uid"value="username"/>
<jsp:param name="pwd"value="password"/>
</jsp:include>
<jsp:includepage="tail.jsp"/>

<jsp:include> ：动态包含

 

第一种情况（<jsp:include>包含的是html文件）：

DynamicInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>                            动态包含                  
     
                          
      
                          
      
                                                                        姓名性别年龄爱好                                                                                             abcd                                                        

 

Header.html ：

     
               动态包含的标题(HTML)

 

运行之后，只生成一个servlet，和上面的代码对应如下：

  out.write("\r\n");     out.write("\r\n");     out.write("\t\r\n");     out.write("\t\t动态包含\r\n");     out.write("\t\r\n");     out.write("\t
     
      \r\n");     out.write("\r\n");     out.write("\t\t");     
      
       org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.html", out, true);     out.write("
       \r\n");     out.write("\r\n");     out.write("\t\t
       
        \r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\t姓名性别年龄爱好\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\tabcd\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\r\n");     out.write("\t\r\n");     out.write("");

 

第二种情况（<jsp:include>包含的是jsp文件）：

DynamicInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>                            动态包含                  
     
                          
      
                          
      
                                                                        姓名性别年龄爱好                                                                                             abcd                                                        

Header.jsp ：

<%@pagecontentType="text/html;charset=gb2312"%>                            
     
                                  动态包含的标题(JSP)                            

运行之后，生成了两个servlet：DynamicInclude_jsp.java和header_jsp.java，这也是为什么 Header.jsp中要写上<%@page contentType="text/html;charset=gb2312"%>和完整的<html></html>和<body></body>，而Header.html不用写的原因。因为前者两个.jsp文件是两个相互独立的整体，它们之间的关系是通过request和reponse来发生的，而后者只是简单的嵌套。两个servlet对应的代码如下：

DynamicInclude_jsp.java：

     out.write("\r\n");     out.write("\r\n");     out.write("\t\r\n");     out.write("\t\t动态包含\r\n");     out.write("\t\r\n");     out.write("\t
     
      \r\n");     out.write("\r\n");     out.write("\t\t");     
      
       org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.jsp", out, true);     out.write("
       \r\n");     out.write("\r\n");     out.write("\t\t
       
        \r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\t姓名性别年龄爱好\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\tabcd\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\r\n");     out.write("\t\r\n");     out.write("");

header_jsp.java:    

     out.write("\r\n");     out.write("\r\n");     out.write("\t\r\n");     out.write("\t\t
     
      \r\n");     out.write("\t\t\t动态包含的标题(JSP)\r\n");     out.write("\t\t\r\n");     out.write("\t\r\n");     out.write("");

 

<%@include%>：静态包含

第一种情况：<%@include%>包含的是jsp文件。

StaticInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>                            静态包含                  
     
                          <%@include file="header.jsp"%>
                         
      
                                                                        姓名性别年龄爱好                                                                                             abcd                                                        

header.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
     
               静态包含的标题(JSP)

 

运行之后，只生成一个servlet，和上面的代码对应如下：

 out.write("\r\n");     out.write("\r\n");     out.write("\t\r\n");     out.write("\t\t静态包含\r\n");     out.write("\t\r\n");     out.write("\t
     
      \r\n");     out.write("\r\n");     out.write("\t\t");     out.write("\r\n");     
      
       out.write("
       
        \r\n");     out.write("\t静态包含的标题(JSP)\r\n");     out.write("");     out.write("
        \r\n");     out.write("\t\t
        
         \r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\t姓名性别年龄爱好\r\n");     out.write("\t\t\t\r\n");      out.write("\t\t\t\r\n");     out.write("\t\t\t\tabcd\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\r\n");     out.write("\t\r\n");     out.write("");

 

第二种情况：<%@include%>包含的是html文件。

StaticInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>                            静态包含                  
     
                          <%@include file="header.html"%>
                         
      
                                                                        姓名性别年龄爱好                                                                                             abcd                                                        

header.html:

<%@pagecontentType="text/html;charset=gb2312"%>
     
               静态包含的标题(HTML)

运行之后，也是只生成一个servlet，和上面的代码对应如下：

 out.write("\r\n");     out.write("\r\n");     out.write("\t\r\n");     out.write("\t\t静态包含\r\n");     out.write("\t\r\n");     out.write("\t
     
      \r\n");     out.write("\r\n");     out.write("\t\t");     out.write("\r\n");     
      
       out.write("
       
        \r\n");     out.write("\t静态包含的标题(HTML)\r\n");     out.write("");     out.write("
        \r\n");     out.write("\t\t
        
         \r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\t姓名性别年龄爱好\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\t\tabcd\r\n");     out.write("\t\t\t\r\n");     out.write("\t\t\r\n");     out.write("\t\r\n");     out.write("");

 

由上可以总结出：

对于静态包含，<%@include%>，中包含的文件，只是简单的嵌入到主文件中，就是在jsp页面转化成Servlet时才嵌入到主文件中，因为运行的结果是只生成了一个Servlet。

而对于动态包含<jsp:incude>，如果被包含文件是动态的，那么就会生成两个Servlet，也就是被包含文件也要经过jsp引擎编译执行生成一个Servlet，两个Servlet通过request和reponse进行通信。如果被包含的文件是静态的，那么这种情况和<%@include>就很相似，只生成了一个Servlet，但是他们之间没有进行简单的嵌入，而依然是通过request和reponse进行的通信。