jsp - forward指令
forward指令 既可以指向静态的html页面,也可以转发到动态的jsp页面,并可以保留先前请求的参数.
例如,在web中新建一个Jsp_src.jsp的jsp页面:
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>原始页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
原始页面. <br>
<jsp:forward page="jsp_target.jsp"></jsp:forward>
</body>
</html>
然后让页面Jsp_src.jsp转到jsp_target.jsp页面,jsp_target.jsp页面的代码为:
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>jsp目标页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
目标页面主体. <br>
<jsp:forward page="jsp_target2.jsp"></jsp:forward>
</body>
</html>
然后,再次在jsp_target.jsp页面中转到新的jsp页面jsp_target2.jsp,代码为:
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>jsp目标页面2</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
目标页面主体2. <br>
req-char:<%=request.getCharacterEncoding() %>
name=<%=request.getParameter("name") %>
</body>
</html>
往浏览器中输入请求url: http://localhost:8080/ServletJSP/forward/Jsp_src.jsp?name=hi
可以看到,浏览器中请求地址依然不变,但内容也变为jsp_target2.jsp的页面的内容,而且,请求的参数name仍然可以保留.
