servlet-3.0 | 易学教程

SpringServletContainerInitializer cannot be cast to javax.servlet.ServletContainerInitializer

阅读更多关于 SpringServletContainerInitializer cannot be cast to javax.servlet.ServletContainerInitializer

问题 I am attempting to move a xml-based Spring MVC app to a Java Configuration based app. There appears to be a mismatch with the various java.servlet classes available in maven. For instance, some provide the addServlet() method and some do not. Here is my config class: public class MyWebAppInitializer implements WebApplicationInitializer { @Override public void onStartup(ServletContext container) throws ServletException { AnnotationConfigWebApplicationContext rootContext = new

How to set tomcat 8 container character encoding of request and response to UTF-8 intead of ISO-8859-1

阅读更多关于 How to set tomcat 8 container character encoding of request and response to UTF-8 intead of ISO-8859-1

问题 We need to set tomcat 8 container character encoding of request and response to UTF-8 intead of ISO-8859-1 , What is the setting for the same We tried setting as mentioned below , https://wiki.apache.org/tomcat/FAQ/CharacterEncoding#Q1 But that requires creating filter etc. Is there any elegant way where we can just change some configuration set to make it applicable at container level 回答1: Tomcat 8+ comes bundled with a filter to set the character encoding. This is described in Tomcat 8

IllegalStateException: Not supported on AsyncContext.startAsync(req, res)

阅读更多关于 IllegalStateException: Not supported on AsyncContext.startAsync(req, res)

问题 I have created a servlet 3.0 to explore asynchronous request processing: @WebServlet(name="MyTest", urlPatterns={"/MyTest"}, asyncSupported=true) public class MyTest extends HttpServlet { @Override public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { AsyncContext tmp = req.startAsync(req, res); ... } } but I get an IllegalStateException when .startAsync(...) is called. I know the Javadoc mentions that exception, but I did explicitly enable

Tomcat 7 session cookie path

阅读更多关于 Tomcat 7 session cookie path

问题 I'm having a huge problem with my application and Tomcat 7. My application needs to set session cookie to "/" path instead of "/context" path. In tomcat 6 it was a matter of adding another property to Connector (emptySessionPath="true") and Tomcat 7 doesn't recognize this thing. I know that Servlet 3.0 spec allows to configure it on per-context basis, but I couldn't make it work with Tomcat 7. It still adds the context path instead of "/". I will be very grateful for the receipt on how to do

Java web app - What determines my Servlet API version? Does it get specified in web.xml?

阅读更多关于 Java web app - What determines my Servlet API version? Does it get specified in web.xml?

问题 I'm using Eclipse EE Juno and my current web application is using Dynamic web modules 2.4 . I'm trying to bump the version up to 3.0 but for some reason I'm unable to. when I try to change the version in project facets I get Cannot change version of project facet Dynamic Web Module to 3.0 . Is it possible that there some bunk line in my web.xml file that determines this? How do I change the Dynamic web modules version if not from Eclipse project facet setting alone? 回答1: Servlet 2.4 in web

Java - Async in Servlet 3.0 vs NIO in Servlet 3.1

阅读更多关于 Java - Async in Servlet 3.0 vs NIO in Servlet 3.1

问题 Until now, as it applies to serving http requests, I thought the terms - asynchronous and non-blocking i/o meant the same thing. But apparently, they have been implemented separately in servlet 3.0 and 3.1 respectively. I am struggling to understand the difference here... Can someone shed more light on this topic, please? Specifically, I am looking for an example of how a servlet 3.0 implementation of a server can be async, yet block on a thread? I think may be if I understand this, it may be

Servlet-3 Async Context, how to do asynchronous writes?

阅读更多关于 Servlet-3 Async Context, how to do asynchronous writes?

问题 Problem Description Servlet-3.0 API allows to detach a request/response context and answer to it later. However if I try to write a big amount of data, something like: AsyncContext ac = getWaitingContext() ; ServletOutputStream out = ac.getResponse().getOutputStream(); out.print(some_big_data); out.flush() It may actually block - and it does block in trivial test cases - for both Tomcat 7 and Jetty 8. The tutorials recommend to create a thread pool that would handle such a setup - witch is

How to avoid request set ASYNC_SUPPORTED=true to enable async servlet 3.0 processing on Tomcat 7?

阅读更多关于 How to avoid request set ASYNC_SUPPORTED=true to enable async servlet 3.0 processing on Tomcat 7?

问题 Following an issue reported on this question, a solution was found: req.setAttribute("org.apache.catalina.ASYNC_SUPPORTED", true); This seems a bit strange and is not really 'portable' code (it won't hurt, but...). It seems specific to Tomcat 7. I am using Tomcat 7.0.14 as delivered by NetBeans 7.0.1. I could not find documentation indicating it is necessary to enable async request processing in servlet 3.0 with a catalina attribute. I could not find documentation indicating something special

Why create new thread with startAsync instead of doing work in servlet thread?

阅读更多关于 Why create new thread with startAsync instead of doing work in servlet thread?

问题 In servlet 3.0 one can use startAsync to put long work in another thread, so that you can free up servlet thread. Seems that I'm missing something, because I don't see, why not just to use servlet thread for working? Is the thread created by startAsync somehow cheaper? 回答1: In most situations when handling requests you are blocking or waiting on some external resource/condition. In this case you are occupying the thread (hence a lot of memory) without doing any work. With servlet 3.0 you can

How to define <welcome-file-list> and <error-page> in servlet 3.0's web.xml-less?

阅读更多关于 How to define and in servlet 3.0's web.xml-less?

I have existing web-app which I want to convert into web.xml-less of servlet's 3.0. I've managed to make it working, however there are 2 tags in web.xml which I still don't know the equivalent code in web.xml-less environment. <welcome-file-list> <welcome-file>/index.jsp</welcome-file> </welcome-file-list> <error-page> <error-code>404</error-code> <location>/pageNotFound</location> </error-page> Any help is appreciated In Servlets 3.0 you don't need a web.xml for many cases, however, sometimes it's required or just useful. Your case is just one of them - there is no special annotations to