<jsp:include> :動態包含
1、<jsp:include>
包含的是html文件
舉例:
DynamicInclude.jsp:
<%@pagecontentType="text/html;charset=gb2312"%>
<html>
<head>
<title>動態包含</title>
</head>
<bodystyle="background-color:lightblue">
<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>
運行之後,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");
org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.html", out, true);
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>");
2、<jsp:include>
包含的是jsp文件
舉例:
DynamicInclude.jsp:
<%@pagecontentType="text/html;charset=gb2312"%>
<html>
<head>
<title>動態包含</title>
</head>
<bodystyle="background-color:lightblue">
<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>
運行之後,生成了兩個servlet:DynamicInclude_jsp.Java和header_jsp.java,這也是爲什麼 Header.jsp中要寫上<%@page contentType=“text/html;charset=gb2312”%>和完整的和,而Header.html不用寫的原因。因爲前者兩個.jsp文件是兩個相互獨立的整體,它們之間的關係是通過request和reponse來發生的,而後者只是簡單的嵌套。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");
org.apache.jasper.runtime.JspRuntimeLibrary.include(request,response, "header.jsp", out, true);
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
1、<%@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="background-color:lightblue">
<%@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>
運行之後,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");
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>");
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>");
2、<%@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="background-color:lightblue">
<%@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>
運行之後,也是隻生成一個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");
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>");
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,因爲運行的結果是隻生成了一個Servlet。
而對於動態包含<jsp:incude>
,如果被包含文件是動態的,那麼就會生成兩個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,那麼這種情況和<%@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。
在jsp中有兩種包含,靜態包含<%@include file=“xxx.jsp”%>和動態包含<jsp:include page=“xxx.jsp”>,下面說一下它們之間的區別
1、<%@include file=“xxx.jsp”%>爲jsp中的編譯指令,其文件的包含是發生在jsp向servlet轉換的時期,而<jsp:include page=“xxx.jsp”>是jsp中的動作指令,其文件的包含是發生在編譯時期,也就是將java文件編譯爲class文件的時期
2、使用靜態包含只會產生一個class文件,而使用動態包含會產生多個class文件
3、使用靜態包含,包含頁面和被包含頁面的request對象爲同一對象,因爲靜態包含只是將被包含的頁面的內容複製到包含的頁面中去;而動態包含包含頁面和被包含頁面不是同一個頁面,被包含的頁面的request對象可以取到的參數範圍要相對大些,不僅可以取到傳遞到包含頁面的參數,同樣也能取得在包含頁面向下傳遞的參數