Jsp中param标签的使用
@Author:ZJ 07-2-21
Blog: [url]http://zhangjunhd.blog.51cto.com/[/url]
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、、一起使用，方法如下：
其中，name为与属性相关联的关键词，value为属性的值。
1．与配合使用
includeAction.jsp
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
    <title>Includetitle>
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>cometitle>
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．与配合使用
用户登录示例
login.jsp
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
    <title>Logintitle>
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>CheckLogintitle>
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>Successtitle>
head>
<body>
    Welcome,<%=request.getParameter("user")%>//获得参数"user"
body>
html>