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<jsp:include>和<%@include%>的区别

2017-02-22 18:35 513 查看
前天上了jsp的课,老师讲了一下<%@include%>和<jsp:include>的区别,由于演示的太快,我没有看太清,所以回来之后,自己又写了个例子,好好看看,还是发现了一些东西的。

<jsp:include> :动态包含

第一种情况(<jsp:include>包含的是html文件):

DynamicInclude.jsp:

[html] view
plain copy

<%@pagecontentType="text/html;charset=gb2312"%>

<html>

<head>

<title>动态包含</title>

</head>

<bodystylebodystyle="background-color:lightblue">

<jsp:include page="header.html"flush="true"/><!--动态包含-->

<tablebordertableborder="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 :

[html] view
plain copy

<h2styleh2style="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:

[java] view
plain copy

out.write("\r\n");

out.write("<html>\r\n");

out.write("\t<head>\r\n");

out.write("\t\t<title>动态包含</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("<!--动态包含-->\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>性别</td><td>年龄</td><td>爱好</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>");

第二种情况(<jsp:include>包含的是jsp文件):

DynamicInclude.jsp:

[html] view
plain copy

<%@pagecontentType="text/html;charset=gb2312"%>

<html>

<head>

<title>动态包含</title>

</head>

<bodystylebodystyle="background-color:lightblue">

<jsp:include page="header.jsp"flush="true"/><!--动态包含-->

<tablebordertableborder="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 :

[html] view
plain copy

<%@pagecontentType="text/html;charset=gb2312"%>

<html>

<body>

<h2styleh2style="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:

[html] view
plain copy

out.write("\r\n");

out.write("<html>\r\n");

out.write("\t<head>\r\n");

out.write("\t\t<title>动态包含</title>\r\n");

out.write("\t</head>\r\n");

out.write("\t<bodystylebodystyle=\"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("<!--动态包含-->\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>性别</td><td>年龄</td><td>爱好</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:

[html] view
plain copy

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动态包含的标题(JSP)\r\n");

out.write("\t\t</h2>\r\n");

out.write("\t</body>\r\n");

out.write("</html>");

[b]<%@include%>:静态包含[/b]

第一种情况:<%@include%>包含的是jsp文件。

StaticInclude.jsp:

[html] view
plain copy

<%@pagecontentType="text/html;charset=gb2312"%>

<html>

<head>

<title>静态包含</title>

</head>

<bodystylebodystyle="background-color:lightblue">

<%@include file="header.jsp"%><!--静态包含-->

<tablebordertableborder="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:

[html] view
plain copy

<%@pagecontentType="text/html;charset=gb2312"%>

<h2styleh2style="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:

[html] view
plain copy

out.write("\r\n");

out.write("<html>\r\n");

out.write("\t<head>\r\n");

out.write("\t\t<title>静态包含</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("<h2styleh2style=\"font-family:arial;color:red;font-size:25px;text-align:center\">\r\n");

out.write("\t静态包含的标题(JSP)\r\n");

out.write("</h2>");</span>

out.write("<!--静态包含-->\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>性别</td><td>年龄</td><td>爱好</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>");

第二种情况:<%@include%>包含的是html文件。

StaticInclude.jsp:

[html] view
plain copy

<%@pagecontentType="text/html;charset=gb2312"%>

<html>

<head>

<title>静态包含</title>

</head>

<bodystylebodystyle="background-color:lightblue">

<%@include file="header.html"%><!--静态包含-->

<tablebordertableborder="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:

[html] view
plain copy

<%@pagecontentType="text/html;charset=gb2312"%>

<h2styleh2style="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:

[html] view
plain copy

out.write("\r\n");

out.write("<html>\r\n");

out.write("\t<head>\r\n");

out.write("\t\t<title>静态包含</title>\r\n");

out.write("\t</head>\r\n");

out.write("\t<bodystylebodystyle=\"background-color:lightblue\">\r\n");

out.write("\r\n");

out.write("\t\t");

out.write("\r\n");

<span style="color:#ff0000;">out.write("<h2styleh2style=\"font-family:arial;color:red;font-size:25px;text-align:center\">\r\n");

out.write("\t静态包含的标题(HTML)\r\n");

out.write("</h2>");</span>

out.write("<!--静态包含-->\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>性别</td><td>年龄</td><td>爱好</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。
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