动作标记的用法详解

<jsp:param>动作标记的用法详解

1.<jsp:param>动作标记的语法

<jsp:param name="attName" value="AttValue"/>

2.<jsp:param>动作标记的作用

指定某个参数的值，必须和<jsp:forward>,<jsp:include>,<jsp:plugin>等一起协同使用

示例：

1．<jsp:param>与<jsp:include>配合使用

includeAction.jsp

<html>

<head>

<metahttp-equiv="Content-Type"content="text/html; charset=GB18030">

<title>Include</title>

</head>

<body>

<%doublei = Math.random();%>

<jsp:includepage="come.jsp">//加载come.jsp

<jsp:paramname="number"value="<%=i%>"/>//传递参数

</jsp:include>

</body>

</html>

come.jsp

<html>

<head>

<metahttp-equiv="Content-Type"content="text/html; charset=GB18030">

<title>come</title>

</head>

<bodybgcolor=cyan>

<FontSize=3>

<%//获得includeAction.jsp传来的值:

String str = request.getParameter("number");

doublen = Double.parseDouble(str);

%>

The value form includeAction is:<br><%=n%>

</Font>

</body>

</html>

2．<jsp:param>与<jsp:forward>配合使用

用户登录示例login.jsp

<html>

<head>

<metahttp-equiv="Content-Type"content="text/html; charset=GB18030">

<title>Login</title>

</head>

<body>

//由checklogin.jsp处理表单数据

<formaction="checklogin.jsp"method="get">

<table>

<tr>

<td>Username:</td>

<td>//获得参数"user"，初始值为null

<inputtype="text"name="username"

value=<%=request.getParameter("user")%>>

</td>

</tr>

<tr>

<td>Password:</td>

<td>

<inputtype="password"name="password">

</td>

</tr>

<tr>

<td>

<inputtype="submit"value="login">

</td>

</tr>

</table>

</form>

</body>

</html>

checklogin.jsp

<html>

<head>

<metahttp-equiv="Content-Type"content="text/html; charset=GB18030">

<title>CheckLogin</title>

</head>

<body>

<%

//与login.jsp中name="username"对应

String name = request.getParameter("username");

//与login.jsp中name="password"对应

String password = request.getParameter("password");

if(name.equals("admin") && password.equals("admin")) {

%>

<jsp:forwardpage="success.jsp">//跳转至success.jsp

<jsp:paramname="user"value="<%=name%>"/>//携带参数"user"

</jsp:forward>

<%

}else{

%>

<jsp:forwardpage="login.jsp">//跳转至login.jsp

<jsp:paramname="user"value="<%=name%>"/>//携带参数"user"

</jsp:forward>

<%

}

%>

</body>

</html>


success.jsp

<html>

<head>

<metahttp-equiv="Content-Type"content="text/html; charset=GB18030">

<title>Success</title>

</head>

<body>

Welcome,<%=request.getParameter("user")%>//获得参数"user"

</body>

</html>