JavaBean四個作用域范圍的詳解

JavaBean四個作用域范圍的詳解

康平網站建設公司成都創新互聯,康平網站設計制作，有大型網站制作公司豐富經驗。已為康平上千提供企業網站建設服務。企業網站搭建\成都外貿網站制作要多少錢，請找那個售后服務好的康平做網站的公司定做！

一說明

使用useBeans的scope屬性可以用來指定javabean的作用范圍。

二四個作用范圍

JavaBean四個作用域范圍的詳解

三代碼

1、login.jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  
  <title>My JSP 'login.jsp' starting page</title>
  
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">  
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
    -->
 
 </head>
 
 <body>
  <h2>系統登錄</h2>
  <hr>
  <form name="loginForm" action="dologin.jsp?mypass=999999" method="post">
   <table>
    <tr>
     <td>用戶名：</td>
     <td><input type="text" name="username" value=""/></td>
    </tr>
    <tr>
     <td>密碼：</td>
     <td><input type="password" name="password" value=""/></td>
    </tr>
    <tr>
     <td colspan="2" align="center"><input type="submit" value="登錄"/></td>
     
    </tr>
   </table>
  </form>
 </body>
</html>

2、dologin.jsp

<%@ page language="java" import="java.util.*" contentType="text/html; charset=utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
  <base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
  
  <title>My JSP 'dologin.jsp' starting page</title>
  
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">  
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    <!--
    <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
    -->
 
 </head>
 
 <body>
  <jsp:useBean id="myUsers" class="com.po.Users" scope="page"/>
  <h2>setProperty動作元素</h2>
  <hr>
  <!--根據表單自動匹配所有的屬性 -->
  <%--
  <jsp:setProperty name="myUsers" property="*"/> 
  --%>
  <!--根據表單匹配所有部分的屬性 -->
  <%--
  <jsp:setProperty name="myUsers" property="username"/> 
  --%>
  <!--根表單無關，通過手工賦值給屬性 -->
  <%--
  <jsp:setProperty name="myUsers" property="username" value="lisi"/>
  <jsp:setProperty name="myUsers" property="password" value="888888"/>
  --%>
  <!--通過URL傳參數給屬性賦值 -->
  <jsp:setProperty name="myUsers" property="username"/>
  <jsp:setProperty name="myUsers" property="password" param="mypass"/>
  <!-- 使用傳統的表達式方式來獲取用戶名和密碼 -->
  <%--  
    用戶名：<%=myUsers.getUsername() %><br>
    密碼：<%=myUsers.getPassword() %><br>
  --%>
  <!-- 使用getProperty方式來獲取用戶名和密碼 -->
   用戶名：<jsp:getProperty name="myUsers" property="username"/> <br>
   密碼：<jsp:getProperty name="myUsers" property="password"/><br>
  <br>
  <br>
 
   <a href="testScope.jsp" rel="external nofollow" >測試javabean的四個作用域范圍</a>
 
   <%
     request.getRequestDispatcher("testScope.jsp").forward(request, response);
   %>
 
 </body>
</html>

3、testScope.jsp

<%@ page language="java" import="java.util.*"
    contentType="text/html; charset=utf-8"%>
<%@ page import="com.po.Users"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://"
            + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>
 
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
 
<title>My JSP 'testScope.jsp' starting page</title>
 
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
    <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" >
    -->
 
</head>
 
<body>
    <h2>Javabean的四個作用域范圍</h2>
    <hr>
    <jsp:useBean id="myUsers" class="com.po.Users" scope="page" />
    用戶名：<jsp:getProperty name="myUsers" property="username" /><br> 密碼：<jsp:getProperty
        name="myUsers" property="password" /><br>
    <!-- 使用內置對象獲取用戶名和密碼 -->
    <hr>
    <%--
    用戶名：<%=((Users)application.getAttribute("myUsers")).getUsername()%><br>
    密碼：<%=((Users)application.getAttribute("myUsers")).getPassword() %><br>
  --%>
    <%--
    用戶名：<%=((Users)session.getAttribute("myUsers")).getUsername()%><br>
    密碼：<%=((Users)session.getAttribute("myUsers")).getPassword() %><br>
  --%>
    <%--
    用戶名：<%=((Users)request.getAttribute("myUsers")).getUsername()%><br>
    密碼：<%=((Users)request.getAttribute("myUsers")).getPassword() %><br>
  --%>
    <%
        String username = "";
        String password = "";
        if (pageContext.getAttribute("myUsers") != null) {
            username = ((Users) pageContext.getAttribute("myUsers"))
                    .getUsername();
            password = ((Users) pageContext.getAttribute("myUsers"))
                    .getPassword();
        }
    %>
 
    用戶名：<%=username%><br> 密碼：<%=password%><br>
 
 
 
</body>
</html>

四測試結果

JavaBean四個作用域范圍的詳解

如有疑問請留言或者到本站社區交流討論，感謝閱讀，希望能幫助到大家，謝謝大家對本站的支持！

新聞標題：JavaBean四個作用域范圍的詳解
分享網址：http://vcdvsql.cn/article42/ggheec.html

成都網站建設公司_創新互聯，為您提供建站公司、全網營銷推廣、微信公眾號、、網站建設、網站制作

聲明：本網站發布的內容（圖片、視頻和文字）以用戶投稿、用戶轉載內容為主，如果涉及侵權請盡快告知，我們將會在第一時間刪除。文章觀點不代表本網站立場，如需處理請聯系客服。電話：028-86922220；郵箱：631063699@qq.com。內容未經允許不得轉載，或轉載時需注明來源：創新互聯

猜你還喜歡下面的內容

bl双性强迫侵犯h_国产在线观看人成激情视频_蜜芽188_被诱拐的少孩全彩啪啪漫画

JavaBean四個作用域范圍的詳解