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：
复制代码 代码如下:
<jsp:param 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 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" value=<%=request.getParameter("user") %>> </td> </tr> <tr> <td>Password:</td> <td> <input type="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 value="<%=name%>" />//携带参数"user" </jsp:forward> <% } else { %> <jsp:forward page="login.jsp">//跳转至login.jsp <jsp:param 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>