Jspparam标签的使用
@Author:ZJ 07-2-21
<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><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><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>
     // 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>
    <%
      //login.jspname="username"对应
       String name = request.getParameter("username");
       //login.jspname="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>