Jsp中param標籤的使用

github_zwl發表於2017-09-09
JS
Jsp中param標籤的使用
<jsp:param>操作被用來以“名-值”對的形式為其他標籤提供附加資訊。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為與屬性相關聯的關鍵詞，value為屬性的值。
1．<jsp:param>與<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">//載入come.jsp
    <jsp:param name="number" value="<%=i%>" />//傳遞引數
</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>
  <%//獲得includeAction.jsp傳來的值:
    String str = request.getParameter("number");
double n = Double.parseDouble(str);
%>
    The value form includeAction is:<br> <%=n%>
</Font>
</body>
</html>
2．<jsp:param>與<jsp:forward>配合使用
使用者登入示例
login.jsp
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=GB18030">
    <title>Login</title>
</head>
<body>
     //由 checklogin.jsp處理表單資料
   <form action="checklogin.jsp" method="get">
        <table>
            <tr>
              <td>Username:</td>
              <td> //獲得引數"user"，初始值為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>
    <%
      //與login.jsp中name="username"對應
       String name = request.getParameter("username");
       //與login.jsp中name="password"對應
String password = request.getParameter("password");
       if (name.equals("admin") && password.equals("admin")) {
    %>
    <jsp:forward page="success.jsp">//跳轉至success.jsp
       <jsp:param name="user" value="<%=name%>" />//攜帶引數"user"
    </jsp:forward>
    <%
    } else {
    %>
    <jsp:forward page="login.jsp">//跳轉至login.jsp
       <jsp:param name="user" value="<%=name%>" />//攜帶引數"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")%>//獲得引數"user"
</body>
</html>

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