javaBean之四个作用域范围

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javaBean之四个作用域范围


代码:

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%>">
    
    <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">
-->


  </head>
  
  <body>
      <h1>系统登录</h1>
      <hr>
      <form action="javaBean/dologin.jsp" name="loginFrom" method="post">
          <table>
              <tr>
                  <td>用户名:</td>
                  <td><input type="text" name="username" value=""></td>
              </tr>
              <tr>
                  <td>密码:</td>
                  <td><input type="password" name="password" value=""></td>
              </tr>
              <tr>
                  <td colspan="2" align="center"><input type="submit" value="登录"></td>
              </tr>
          </table>
      </form>
      
  </body>
</html>









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%>">
    
    <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">
-->


  </head>
  
  <body>
      <jsp:useBean id="myUsers" class="com.user.Users" scope="aoolication" />
      <h1>setProperty动作元素</h1>
      <hr>
      <!-- 根据表单自动匹配所有的属性     ,name=""和上面useBean的Id对应 -->
      <jsp:setProperty  name="myUsers" property="*" />
                     用户名:<%=myUsers.getUsername() %><br>
                     密码:<%=myUsers.getPassword() %>
      <br>
      <a href="javaBean/testScope.jsp">测试javaBean的四个作用域范围</a>
      
  </body>
</html>






testScope.jsp:

<jsp:useBean id="myUsers" class="com.user.Users" scope="application"></jsp:useBean>







page:当前页面有效,超链接过去无效

application:全局,作用于整个web应用,超链接过去有效

request:用作单个请求,超链接过去无效,如需使用

               <%
                        request.getRequestDispatcher("testScope.jsp").forword(request,response);
               %>

session:用作整个会话,超链接过去有效




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