jsp頁面包含的幾中方式


(1)include指令

          include指令告訴容器:復制被包含文件匯總的所有內容,再把它粘貼到這個文件中。

<%@ include file="Header.jsp"%>

(2)include標准動作

<jsp:include page="Header.jsp"/>

(3)采用JSTL

<c:import url="http://www.sina.com/index.html">

 

<jsp:include>和<%@include%>的區別

<%@include%>和<jsp:include>的區別,發現了一些東西的。

 

 

<%@include%>:頁面請求之前預編譯,所有代碼包含進來之后,一起進行處理,把所有代碼合在一起,編譯成一個servlet

<jsp:include>:所有代碼分別處理,在頁面被請求的時候才編譯,被編譯成多個servlet,頁面語法相對獨立,處理完成之后再將代碼的顯示結果(處理結果)組合進來。


JSP中的兩種包含頁面的方法
第一種:include指令:當JSP轉換成Servlet時引入指定文件

<%@ pagecontentType="text/html;charset=GB2312" language="java"errorPage=""%>
<%@ include file="head.jsp"%>
<%@ include file="body.jsp"%>
<%@ include file="tail.jsp"%>
第二種:<jsp:include>動作元素:當JSP頁面被請求時引入指定文件
<%@ page contentType="text/html; charset=GB2312"language="java" errorPage=""%>
<jsp:include page="head.jsp"/>
<jsp:include page="body.jsp"/>
<jsp:include page="tail.jsp"/>
第二種方法可以很方便的用<jsp:param>來向所包含頁傳遞參數,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> :動態包含

 

第一種情況(<jsp:include>包含的是html文件):

DynamicInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
<html>
         <head>
                   <title>動態包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <jsp:include page="header.html"flush="true"/><!--動態包含-->
 
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>
                            </tr>
                            <tr>
                                     <td>a</td><td>b</td><td>c</td><td>d</td>
                            </tr>
                   </table>
         </body>
</html>

 

Header.html :

<h2style="font-family:arial;color:red;font-size:25px;text-align:center">
         動態包含的標題(HTML)
</h2>

 

運行之后,只生成一個servlet,和上面的代碼對應如下:

  out.write("\r\n");
     out.write("<html>\r\n");
     out.write("\t<head>\r\n");
     out.write("\t\t<title>動態包含</title>\r\n");
     out.write("\t</head>\r\n");
     out.write("\t<bodystyle=\"background-color:lightblue\">\r\n");
     out.write("\r\n");
     out.write("\t\t");
     <span style="color:#ff0000;">org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.html", out, true);</span>
     out.write("<!--動態包含-->\r\n");
     out.write("\r\n");
     out.write("\t\t<table border=\"1\"align=\"center\">\r\n");
     out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
     out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>a</td><td>b</td><td>c</td><td>d</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
     out.write("\t\t</table>\r\n");
     out.write("\t</body>\r\n");
     out.write("</html>");

 

第二種情況(<jsp:include>包含的是jsp文件):

DynamicInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
<html>
         <head>
                   <title>動態包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <jsp:include page="header.jsp"flush="true"/><!--動態包含-->
 
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>
                            </tr>
                            <tr>
                                     <td>a</td><td>b</td><td>c</td><td>d</td>
                            </tr>
                   </table>
         </body>
</html>

Header.jsp :

<%@pagecontentType="text/html;charset=gb2312"%>
<html>
         <body>
                   <h2style="font-family:arial;color:red;font-size:25px;text-align:center">
                            動態包含的標題(JSP)
                   </h2>
         </body>
</html>

運行之后,生成了兩個servlet:DynamicInclude_jsp.java和header_jsp.java,這也是為什么 Header.jsp中要寫上<%@page contentType="text/html;charset=gb2312"%>和完整的<html></html>和<body></body>,而Header.html不用寫的原因。因為前者兩個.jsp文件是兩個相互獨立的整體,它們之間的關系是通過request和reponse來發生的,而后者只是簡單的嵌套。兩個servlet對應的代碼如下:

 

DynamicInclude_jsp.java:

     out.write("\r\n");
     out.write("<html>\r\n");
     out.write("\t<head>\r\n");
     out.write("\t\t<title>動態包含</title>\r\n");
     out.write("\t</head>\r\n");
     out.write("\t<bodystyle=\"background-color:lightblue\">\r\n");
     out.write("\r\n");
     out.write("\t\t");
     <span style="color:#ff0000;">org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.jsp", out, true);</span>
     out.write("<!--動態包含-->\r\n");
     out.write("\r\n");
     out.write("\t\t<table border=\"1\"align=\"center\">\r\n");
     out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
     out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>a</td><td>b</td><td>c</td><td>d</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
     out.write("\t\t</table>\r\n");
     out.write("\t</body>\r\n");
     out.write("</html>");

header_jsp.java:    

     out.write("\r\n");
     out.write("<html>\r\n");
     out.write("\t<body>\r\n");
     out.write("\t\t<h2 style=\"font-family:arial;color:red;font-size:25px;text-align:center\">\r\n");
     out.write("\t\t\t動態包含的標題(JSP)\r\n");
     out.write("\t\t</h2>\r\n");
     out.write("\t</body>\r\n");
     out.write("</html>");

 

<%@include%>:靜態包含

第一種情況:<%@include%>包含的是jsp文件。

StaticInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
<html>
         <head>
                   <title>靜態包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <%@include file="header.jsp"%><!--靜態包含-->
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>
                            </tr>
                            <tr>
                                     <td>a</td><td>b</td><td>c</td><td>d</td>
                            </tr>
                   </table>
         </body>
</html>

header.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
<h2style="font-family:arial;color:red;font-size:25px;text-align:center">
         靜態包含的標題(JSP)
</h2>

 

運行之后,只生成一個servlet,和上面的代碼對應如下:

 out.write("\r\n");
     out.write("<html>\r\n");
     out.write("\t<head>\r\n");
     out.write("\t\t<title>靜態包含</title>\r\n");
     out.write("\t</head>\r\n");
     out.write("\t<body style=\"background-color:lightblue\">\r\n");
     out.write("\r\n");
     out.write("\t\t");
     out.write("\r\n");
     <span style="color:#ff0000;">out.write("<h2style=\"font-family:arial;color:red;font-size:25px;text-align:center\">\r\n");
     out.write("\t靜態包含的標題(JSP)\r\n");
     out.write("</h2>");</span>
     out.write("<!--靜態包含-->\r\n");
     out.write("\t\t<table border=\"1\"align=\"center\">\r\n");
     out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
      out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>a</td><td>b</td><td>c</td><td>d</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
     out.write("\t\t</table>\r\n");
     out.write("\t</body>\r\n");
     out.write("</html>");

 

第二種情況:<%@include%>包含的是html文件。

StaticInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
<html>
         <head>
                   <title>靜態包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <%@include file="header.html"%><!--靜態包含-->
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>
                            </tr>
                            <tr>
                                     <td>a</td><td>b</td><td>c</td><td>d</td>
                            </tr>
                   </table>
         </body>
</html>

header.html:

<%@pagecontentType="text/html;charset=gb2312"%>
<h2style="font-family:arial;color:red;font-size:25px;text-align:center">
         靜態包含的標題(HTML)
</h2>

運行之后,也是只生成一個servlet,和上面的代碼對應如下:

 out.write("\r\n");
     out.write("<html>\r\n");
     out.write("\t<head>\r\n");
     out.write("\t\t<title>靜態包含</title>\r\n");
     out.write("\t</head>\r\n");
     out.write("\t<bodystyle=\"background-color:lightblue\">\r\n");
     out.write("\r\n");
     out.write("\t\t");
     out.write("\r\n");
     <span style="color:#ff0000;">out.write("<h2style=\"font-family:arial;color:red;font-size:25px;text-align:center\">\r\n");
     out.write("\t靜態包含的標題(HTML)\r\n");
     out.write("</h2>");</span>
     out.write("<!--靜態包含-->\r\n");
     out.write("\t\t<table border=\"1\"align=\"center\">\r\n");
     out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>姓名</td><td>性別</td><td>年齡</td><td>愛好</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
     out.write("\t\t\t<tr>\r\n");
     out.write("\t\t\t\t<td>a</td><td>b</td><td>c</td><td>d</td>\r\n");
     out.write("\t\t\t</tr>\r\n");
     out.write("\t\t</table>\r\n");
     out.write("\t</body>\r\n");
     out.write("</html>");

 

由上可以總結出:

對於靜態包含,<%@include%>,中包含的文件,只是簡單的嵌入到主文件中,就是在jsp頁面轉化成Servlet時才嵌入到主文件中,因為運行的結果是只生成了一個Servlet。

而對於動態包含<jsp:incude>,如果被包含文件是動態的,那么就會生成兩個Servlet,也就是被包含文件也要經過jsp引擎編譯執行生成一個Servlet,兩個Servlet通過request和reponse進行通信。如果被包含的文件是靜態的,那么這種情況和<%@include>就很相似,只生成了一個Servlet,但是他們之間沒有進行簡單的嵌入,而依然是通過request和reponse進行的通信。


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