<!-- JSP page -->
...
<%......
session.setAttribute("testSession","Hello session");
reqeust.setAttribute("testRequest","Hello request");
%>
<a href="JspServlet?action=toServlet">點擊</a>
<form action="JspServlet?action=toServlet" method="post" name="form">
<input name="username" type="test" />
<input type="submit" value="submit">
</form>
...

<servlet-name>JspServlet1</servlet-name>
<servlet-class>com.demo.JspServletDemo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>JspServlet1</servlet-name>
<url-pattern>/JspServlet</url-pattern>
</servlet-mapping>
<servlet-name>JspServlet2</servlet-name>
<servlet-class>com.demo.JspServletDemo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>JspServlet2</servlet-name>
<url-pattern>/admin/JspServlet</url-pattern>
</servlet-mapping>

if(request.getSession(false)==null)
System.out.println("Session has been invalidated!");
else
System.out.println("Session is active!");

String fr="good well";
request.setAttribute("test", fr);
RequestDispatcher de=request.getRequestDispatcher("/test.jsp");
de.forward(request, response);