移除JavaBean

分别通过调用pageContext，request，session，application的removeAttribute(String name)方法，来移除page范围，request范围，session范围，application范围的JavaBean。name为实例化的对象名。

范例： 设置不同范围的JavaBean，并判断是否能访问。
RemoveJavaBean.jsp

<%@ page language = "java" pageEncoding = "gb2312" %>
<html>
     <head>
          <title>
                RemoveJavaBean
          </title>
    </head>
    <body>
          <%-- 设置各个范围的实例化对象 --%>
        <jsp:useBean id = "page_Teacher" scope = "page" class = "com.MyJavaBean.text.Teacher"></jsp:useBean>
        <jsp:useBean id = "request_Teacher" scope = "request" class = "com.MyJavaBean.text.Teacher"></jsp:useBean>
        <jsp:useBean id = "session_Teacher" scope = "session" class = "com.MyJavaBean.text.Teacher"></jsp:useBean>
        <jsp:useBean id = "application_Teacher" scope = "application" class = "com.MyJavaBean.text.Teacher"></jsp:useBean>
        <h1>移除前是否能访问JavaBean？</h1>
        page范围：${!empty page_Teacher}<br>
        request范围：${!empty request_Teacher}<br>
        session范围：${!empty session_Teacher}<br>
        application范围：${!empty application_Teacher}<br>
        <%-- 移除各个范围的JavaBean --%>
        <% 
           pageContext.removeAttribute("page_Teacher");
           request.removeAttribute("request_Teacher");
           session.removeAttribute("session_Teacher");
           application.removeAttribute("application_Teacher");
         %> 
        <h1>移除后是否能访问JavaBean？</h1>
        page范围：${!empty page_Teacher}<br>
        request范围：${!empty request_Teacher}<br>
        session范围：${!empty session_Teacher}<br>
        application范围：${!empty application_Teacher}<br>
    </body>
</html>

在浏览器输入http://localhost:8080/JavaWeb04/RemoveJavaBean.jsp。如下图：
移除JavaBean
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移除JavaBean

移除JavaBean

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