j2ee四大作用域pagecontext,request,session,ServletContext

╰+攻爆jí腚メ 2022-08-22 01:30 133阅读 0赞

在JSP页面中的对象，包括用户创建的对象（例如，JavaBean对象）和JSP的隐含对象，都有一个范围属性。范围定义了在什么时间内，在哪一个JSP页面中可以访问这些对象。例如session对象在会话期间内，可以在多个页面中被访问。application对象在整个Web应用程序的生命周期中都可以被访问。在JSP中，有4种范围，如下所示。

**一,page范围–PageContext域**

具有page范围的对象被绑定到javax.servlet.jsp.PageContext对象中。在这个范围内的对象，只能在创建对象的页面中访问。可以调用pageContext这个隐含对象的getAttribute()方法来访问具有这种范围类型的对象（pageContext对象还提供了访问其他范围对象的getAttribute方法），pageContext对象本身也属于page范围。当Servlet类的\_jspService()方法执行完毕，属于page范围的对象的引用将被丢弃。page范围内的对象，在客户端每次请求JSP页面时创建，在页面向客户端发送回响应或请求被转发（forward）到其他的资源后被删除。

**二,request范围–Request域**

具有request范围的对象被绑定到javax.servlet.ServletRequest对象中，可以调用request这个隐含对象的getAttribute()方法来访问具有这种范围类型的对象。在调用forward()方法转向的页面或者调用include()方法包含的页面中，都可以访问这个范围内的对象。要注意的是，因为请求对象对于每一个客户请求都是不同的，所以对于每一个新的请求，都要重新创建和删除这个范围内的对象。

request对象的主要方法：

Java

**三,session范围–Session域**

具有session范围的对象被绑定到javax.servlet.http.HttpSession对象中，可以调用session这个隐含对象的getAttribute()方法来访问具有这种范围类型的对象。JSP容器为每一次会话，创建一个HttpSession对象，在会话期间，可以访问session范围内的对象。

Session对象的主要方法：

Java

<table style="max-width:100%; font-size:12px; margin-left:0px; border-collapse:collapse!important; border-spacing:0px!important; border:none!important; padding:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-top:0px!important; width:auto!important; table-layout:auto!important; background:none!important"> 
 <tbody> 
  <tr style="padding:0px!important; border:none!important; vertical-align:top!important; margin:0px!important; background:0px 50%"> 
   <td style="font-family:Consolas,ConsolasRegular,'Courier New',monospace!important; vertical-align:top!important; border-bottom-width:0px; padding:0px 5px 0px 0px!important; margin:0px!important; border-right-style:solid!important; border-right-width:3px!important; border-right-color:rgb(108,226,108)!important; border-top-width:0px; border-left-width:0px; color:rgb(175,175,175)!important; background:0px 50%"> 
    <div style="border:0px; padding:0px; margin:0px; white-space:nowrap; font-size:14px!important; line-height:15px!important; background:0px 50%"> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       1 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       2 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       3 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       4 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       5 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       6 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       7 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       8 
     </div> 
    </div> </td> 
   <td style="font-family:Consolas,ConsolasRegular,'Courier New',monospace!important; vertical-align:top!important; border:0px; padding:0px!important; margin:0px!important; width:884px; background:0px 50%"> 
    <div style="padding:0px; margin:0px; white-space:pre; overflow:visible; border:none!important; font-size:14px!important; line-height:15px!important; background:none!important"> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">1</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">getAttribute</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">String</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">name</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">return</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">Object</span>&nbsp;&nbsp;&nbsp; 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">2</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">getAttributeNames</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">return</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">Enumeration</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">3</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">getCreationTime</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">return</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">long</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">4</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">getId</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">return</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">String</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">5</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">GetLastAccessedTime</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">return</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">long</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">6</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">GetMaxInactiveInterval</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">return</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">int</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">7</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">RemoveAttribute</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">String</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">name</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">void</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(206,0,0)!important">8</span>、&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">SetAttribute</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">String</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important">name</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">,</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">java</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">lang</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">Object</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">value</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span>&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(128,0,128)!important">void</span> 
     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

**四,application范围–ServletContext域**

具有application范围的对象被绑定到javax.servlet.ServletContext中，可以调用application这个隐含对象的getAttribute()方法来访问具有这种范围类型的对象。在Web应用程序运行期间，所有的页面都可以访问在这个范围内的对象。

application对象的主要方法：

Java

在web.xml中配置初始化参数

在<web-app>下配置

Java

读取web.xml中的参数

Java

下面我们通过几个简单的例子，来看一下这4种范围对象的应用。

1．测试page范围

test1.jsp

Java

<table style="max-width:100%; font-size:12px; margin-left:0px; border-collapse:collapse!important; border-spacing:0px!important; border:none!important; padding:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-top:0px!important; width:auto!important; table-layout:auto!important; background:none!important"> 
 <tbody> 
  <tr style="padding:0px!important; border:none!important; vertical-align:top!important; margin:0px!important; background:0px 50%"> 
   <td style="font-family:Consolas,ConsolasRegular,'Courier New',monospace!important; vertical-align:top!important; border-bottom-width:0px; padding:0px 5px 0px 0px!important; margin:0px!important; border-right-style:solid!important; border-right-width:3px!important; border-right-color:rgb(108,226,108)!important; border-top-width:0px; border-left-width:0px; color:rgb(175,175,175)!important; background:0px 50%"> 
    <div style="border:0px; padding:0px; margin:0px; white-space:nowrap; font-size:14px!important; line-height:15px!important; background:0px 50%"> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       1 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       2 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       3 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       4 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       5 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       6 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       7 
     </div> 
    </div> </td> 
   <td style="font-family:Consolas,ConsolasRegular,'Courier New',monospace!important; vertical-align:top!important; border:0px; padding:0px!important; margin:0px!important; width:884px; background:0px 50%"> 
    <div style="padding:0px; margin:0px; white-space:pre; overflow:visible; border:none!important; font-size:14px!important; line-height:15px!important; background:none!important"> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(255,0,0)!important">&lt;%</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important">
       &nbsp;&nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">pageContext</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">setAttribute</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"name"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">,</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"yxkong"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%">
       &nbsp;&nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">out</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">println</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"test1.jsp:&nbsp;"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important">
       &nbsp;&nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">out</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">println</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">pageContext</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">getAttribute</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"name"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%">
       &nbsp;&nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">out</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">println</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"&lt;p&gt;"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important">
       &nbsp;&nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">pageContext</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">include</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"test2.jsp"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(255,0,0)!important">%&gt;</span> 
     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

test2.jsp

Java

访问test1.jsp，将看到如下的输出：

test1.jsp: yxkong

test2.jsp: null

说明保存在pageContext对象中的属性具有page范围，只能在同一个页面中被访问。

2．测试request范围

修改test1.jsp和test2.jsp，如下所示。

test1.jsp

Java

<table style="max-width:100%; font-size:12px; margin-left:0px; border-collapse:collapse!important; border-spacing:0px!important; border:none!important; padding:0px!important; margin-right:0px!important; margin-bottom:0px!important; margin-top:0px!important; width:auto!important; table-layout:auto!important; background:none!important"> 
 <tbody> 
  <tr style="padding:0px!important; border:none!important; vertical-align:top!important; margin:0px!important; background:0px 50%"> 
   <td style="font-family:Consolas,ConsolasRegular,'Courier New',monospace!important; vertical-align:top!important; border-bottom-width:0px; padding:0px 5px 0px 0px!important; margin:0px!important; border-right-style:solid!important; border-right-width:3px!important; border-right-color:rgb(108,226,108)!important; border-top-width:0px; border-left-width:0px; color:rgb(175,175,175)!important; background:0px 50%"> 
    <div style="border:0px; padding:0px; margin:0px; white-space:nowrap; font-size:14px!important; line-height:15px!important; background:0px 50%"> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       1 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       2 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       3 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       4 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       5 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       6 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; text-align:center; height:15px; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; background:0px 50%">
       7 
     </div> 
    </div> </td> 
   <td style="font-family:Consolas,ConsolasRegular,'Courier New',monospace!important; vertical-align:top!important; border:0px; padding:0px!important; margin:0px!important; width:884px; background:0px 50%"> 
    <div style="padding:0px; margin:0px; white-space:pre; overflow:visible; border:none!important; font-size:14px!important; line-height:15px!important; background:none!important"> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(255,0,0)!important">&lt;%</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important">
       &nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">request</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">setAttribute</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"name"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">,</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"yxkong"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%">
       &nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">out</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">println</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"test1.jsp:&nbsp;"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important">
       &nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">out</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">println</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">request</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">getAttribute</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"name"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%">
       &nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">out</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">println</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"&lt;p&gt;"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:rgb(249,249,249)!important">
       &nbsp;&nbsp; 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,45,122)!important">pageContext</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">.</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,78,208)!important">include</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">(</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(0,128,0)!important">"test2.jsp"</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">)</span> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(51,51,51)!important">;</span> 
     </div> 
     <div style="font-family:inherit; border:0px; padding:0px 5px; margin:0px; height:inherit; word-break:break-all; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; white-space:pre-wrap!important; background:0px 50%"> 
      <span style="font-family:inherit; height:inherit; font-size:inherit!important; line-height:inherit!important; font-weight:inherit!important; color:rgb(255,0,0)!important">%&gt;</span> 
     </div> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

test2.jsp

Java

访问test1.jsp，将看到如下的输出：

test1.jsp: yxkong

test2.jsp: yxkong

说明保存在request对象中的属性具有request范围，在请求对象存活期间，可以访问这个范围内的对象。

将pageContext.include("test2.jsp"); 这一句注释起来，先访问test1.jsp，再访test2.jsp，可以看到如下输出：

test2.jsp: null

这是因为客户端开始了一个新的请求。

3．测试session范围

修改test1.jsp和test2.jsp，如下所示。

test1.jsp