[英]servlet not forwarding session attribute to jsp
Using embedded tomcat, this code works: 使用嵌入式tomcat,此代码有效:
Servlet : Servlet :
String test = "test";
request.setAttribute("test", test);
request.getRequestDispatcher("/index.jsp").forward(request, response);
JSP : JSP :
<%= request.getAttribute("test") %>
It sets the attribute test
and then prints it out on the servlet /example
's jsp page example.jsp
. 它设置属性test
,然后在servlet /example
的jsp页面example.jsp
上打印出来。
However, if I try to set the attribute within the session then I don't get the same result, instead, I get a null
when using this: 但是,如果我尝试在会话中设置属性,那么我得不到相同的结果,相反,我使用它时得到一个null
:
Servlet : Servlet :
String test = "test";
request.getSession().setAttribute("test", test);
request.getRequestDispatcher("/index.jsp").forward(request, response);
JSP : JSP :
<%= session.getAttribute("test") %>
On the JSP side, you don't need to say request.getSession()
, just session.getAttribute();
在JSP方面,您不需要说request.getSession()
,只需说session.getAttribute();
And you had a problem in your Main.java when creating the servlet context (a trick of using embedded Tomcat); 在创建servlet上下文时,你在Main.java中遇到了问题(使用嵌入式Tomcat的技巧); you were not getting the context created by adding the webapp to tomcat, you had some other context. 你没有通过将webapp添加到tomcat来创建上下文,你还有其他一些上下文。
// File base = new File("src/main/webapp");
// context = tomcat.addContext("", base.getAbsolutePath());
// tomcat.addWebapp(null, "/", base.getAbsolutePath());
context = tomcat.addWebapp("/", new File("src/main/webapp").getAbsolutePath());
context.setSessionTimeout(10080);
I commented out your code and changed the context handling and now things work. 我注释掉了你的代码并改变了上下文处理,现在事情正常。 And a new exception to be caught. 还有一个新的例外。
} catch (ServletException | InterruptedException | LifecycleException exception) {
You may want to compare the session id in the servlet and the jsp. 您可能希望比较servlet和jsp中的会话ID。 If they are different maybe check your session and cookie configuration in tomcat 如果它们不同,可以在tomcat中检查您的会话和cookie配置
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.