Jsp中param标签的使用

Jsp中param标签的使用

<jsp:param>操作被用来以“名-值”对的形式为其他标签提供附加信息。它和<jsp:include>、<jsp:forward>、<jsp:plugin>一起使用，方法如下：

<jsp:param name=”paramName” value=”paramValue”/>

其中，name为与属性相关联的关键词，value为属性的值。

1．<jsp:param>与<jsp:include>配合使用

includeAction.jsp

<html> <head>     <meta http-equiv="Content-Type" content="text/html; charset=GB18030">     <title>Include</title> </head> <body>     <%double i = Math.random();%>     <jsp:include page="come.jsp">//加载come.jsp     <jsp:param name="number" value="<%=i%>" />//传递参数 </jsp:include> </body> </html>

 

come.jsp

<html> <head>     <meta http-equiv="Content-Type" content="text/html; charset=GB18030">     <title>come</title> </head> <body bgcolor=cyan>   <Font Size=3>   <%//获得includeAction.jsp传来的值:     String str = request.getParameter("number"); double n = 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>     <meta http-equiv="Content-Type" content="text/html; charset=GB18030">     <title>Login</title> </head> <body>      //由 checklogin.jsp处理表单数据    <form action="checklogin.jsp" method="get">         <table>             <tr>               <td>Username:</td>               <td> //获得参数"user"，初始值为null                   <input type="text" name="username"                      value=<%=request.getParameter("user") %>>               </td>            </tr>            <tr>               <td>Password:</td>               <td>                   <input type="password" name="password">               </td>            </tr>            <tr>               <td>                   <input type="submit" value="login">               </td>            </tr>        </table>     </form> </body> </html>

 

checklogin.jsp

<html> <head>     <meta http-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:forward page="success.jsp">//跳转至success.jsp        <jsp:param name="user" value="<%=name%>" />//携带参数"user"     </jsp:forward>     <%     } else {     %>     <jsp:forward page="login.jsp">//跳转至login.jsp        <jsp:param name="user" value="<%=name%>" />//携带参数"user"     </jsp:forward>     <%     }     %> </body> </html>

success.jsp

<html> <head>     <meta http-equiv="Content-Type" content="text/html; charset=GB18030">     <title>Success</title> </head> <body>     Welcome,<%=request.getParameter("user")%>//获得参数"user" </body> </html>