jsp页面包含的几中方式

(1)include指令

          include指令告诉容器:复制被包含文件汇总的所有内容,再把它粘贴到这个文件中。

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

(2)include标准动作

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

(3)采用JSTL

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

<jsp:include>和<%@include%>的区别

<%@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"%>
<html>
         <head>
                   <title>动态包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <jsp:include page="header.html"flush="true"/><!--动态包含-->
 
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性别</td><td>年龄</td><td>爱好</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">
         动态包含的标题(HTML)
</h2>

 

运行之后,只生成一个servlet,和上面的代码对应如下:

  out.write("
");
     out.write("<html>
");
     out.write("	<head>
");
     out.write("		<title>动态包含</title>
");
     out.write("	</head>
");
     out.write("	<bodystyle="background-color:lightblue">
");
     out.write("
");
     out.write("		");
     <span style="color:#ff0000;">org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.html", out, true);</span>
     out.write("<!--动态包含-->
");
     out.write("
");
     out.write("		<table border="1"align="center">
");
     out.write("			<tr>
");
     out.write("				<td>姓名</td><td>性别</td><td>年龄</td><td>爱好</td>
");
     out.write("			</tr>
");
     out.write("			<tr>
");
     out.write("				<td>a</td><td>b</td><td>c</td><td>d</td>
");
     out.write("			</tr>
");
     out.write("		</table>
");
     out.write("	</body>
");
     out.write("</html>");

第二种情况(<jsp:include>包含的是jsp文件):

DynamicInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
<html>
         <head>
                   <title>动态包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <jsp:include page="header.jsp"flush="true"/><!--动态包含-->
 
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性别</td><td>年龄</td><td>爱好</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">
                            动态包含的标题(JSP)
                   </h2>
         </body>
</html>

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("
");
     out.write("<html>
");
     out.write("	<head>
");
     out.write("		<title>动态包含</title>
");
     out.write("	</head>
");
     out.write("	<bodystyle="background-color:lightblue">
");
     out.write("
");
     out.write("		");
     <span style="color:#ff0000;">org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.jsp", out, true);</span>
     out.write("<!--动态包含-->
");
     out.write("
");
     out.write("		<table border="1"align="center">
");
     out.write("			<tr>
");
     out.write("				<td>姓名</td><td>性别</td><td>年龄</td><td>爱好</td>
");
     out.write("			</tr>
");
     out.write("			<tr>
");
     out.write("				<td>a</td><td>b</td><td>c</td><td>d</td>
");
     out.write("			</tr>
");
     out.write("		</table>
");
     out.write("	</body>
");
     out.write("</html>");

header_jsp.java:    

     out.write("
");
     out.write("<html>
");
     out.write("	<body>
");
     out.write("		<h2 style="font-family:arial;color:red;font-size:25px;text-align:center">
");
     out.write("			动态包含的标题(JSP)
");
     out.write("		</h2>
");
     out.write("	</body>
");
     out.write("</html>");

<%@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"%>
<html>
         <head>
                   <title>静态包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <%@include file="header.jsp"%><!--静态包含-->
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性别</td><td>年龄</td><td>爱好</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">
         静态包含的标题(JSP)
</h2>

 

运行之后,只生成一个servlet,和上面的代码对应如下:

 out.write("
");
     out.write("<html>
");
     out.write("	<head>
");
     out.write("		<title>静态包含</title>
");
     out.write("	</head>
");
     out.write("	<body style="background-color:lightblue">
");
     out.write("
");
     out.write("		");
     out.write("
");
     <span style="color:#ff0000;">out.write("<h2style="font-family:arial;color:red;font-size:25px;text-align:center">
");
     out.write("	静态包含的标题(JSP)
");
     out.write("</h2>");</span>
     out.write("<!--静态包含-->
");
     out.write("		<table border="1"align="center">
");
     out.write("			<tr>
");
     out.write("				<td>姓名</td><td>性别</td><td>年龄</td><td>爱好</td>
");
     out.write("			</tr>
");
      out.write("			<tr>
");
     out.write("				<td>a</td><td>b</td><td>c</td><td>d</td>
");
     out.write("			</tr>
");
     out.write("		</table>
");
     out.write("	</body>
");
     out.write("</html>");

第二种情况:<%@include%>包含的是html文件。

StaticInclude.jsp:

<%@pagecontentType="text/html;charset=gb2312"%>
<html>
         <head>
                   <title>静态包含</title>
         </head>
         <bodystyle=" margin: 0px; padding: 0px; color: rgb(0, 0, 255);">>
 
                   <%@include file="header.html"%><!--静态包含-->
                   <tableborder="1" align="center">
                            <tr>
                                     <td>姓名</td><td>性别</td><td>年龄</td><td>爱好</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">
         静态包含的标题(HTML)
</h2>

运行之后,也是只生成一个servlet,和上面的代码对应如下:

 out.write("
");
     out.write("<html>
");
     out.write("	<head>
");
     out.write("		<title>静态包含</title>
");
     out.write("	</head>
");
     out.write("	<bodystyle="background-color:lightblue">
");
     out.write("
");
     out.write("		");
     out.write("
");
     <span style="color:#ff0000;">out.write("<h2style="font-family:arial;color:red;font-size:25px;text-align:center">
");
     out.write("	静态包含的标题(HTML)
");
     out.write("</h2>");</span>
     out.write("<!--静态包含-->
");
     out.write("		<table border="1"align="center">
");
     out.write("			<tr>
");
     out.write("				<td>姓名</td><td>性别</td><td>年龄</td><td>爱好</td>
");
     out.write("			</tr>
");
     out.write("			<tr>
");
     out.write("				<td>a</td><td>b</td><td>c</td><td>d</td>
");
     out.write("			</tr>
");
     out.write("		</table>
");
     out.write("	</body>
");
     out.write("</html>");

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。

原文地址:https://www.cnblogs.com/ConfidentLiu/p/7682531.html