急~Struts2 Spring和Hibernate整合时 有关文本输出的Action抛异常
只是做了一个返回文本的Action

XML code

<action name="user" class="userAction" >            <result name="success" type="plainText"></result>        </action>

Java code

@SuppressWarnings("serial")public class UserAction extends ActionSupport{    public String doLogout(){                try {            HttpServletResponse response = ServletActionContext.getResponse();                         ActionContext.getContext().getSession().clear();                        PrintWriter out = response.getWriter();                  response.setContentType("text/plain;charset=utf-8");               response.setHeader("Cache-Control", "no-cache");               out.write("{'msg':'"+StringUtil.chinaToUnicode("你安全退出了！")+"'}");                     } catch (Exception e) {            // TODO: handle exception        }        finally{            return SUCCESS;        }            }    }

2010-11-29 14:49:03 org.apache.jasper.runtime.JspFactoryImpl internalGetPageContext
严重: Exception initializing page context
java.lang.IllegalStateException: Cannot create a session after the response has been committed
at org.apache.catalina.connector.Request.doGetSession(Request.java:2377)
at org.apache.catalina.connector.Request.getSession(Request.java:2097)
at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:833)
at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:216)
at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:547)
at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:493)
at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:224)
at org.apache.jasper.runtime.PageContextImpl._initialize(PageContextImpl.java:146)
at org.apache.jasper.runtime.PageContextImpl.initialize(PageContextImpl.java:124)
at org.apache.jasper.runtime.JspFactoryImpl.internalGetPageContext(JspFactoryImpl.java:107)
at org.apache.jasper.runtime.JspFactoryImpl.getPageContext(JspFactoryImpl.java:63)
at org.apache.jsp.error_jsp._jspService(error_jsp.java:50)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:377)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:646)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:551)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:488)
at org.apache.struts2.dispatcher.ServletDispatcherResult.doExecute(ServletDispatcherResult.java:156)
at org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:186)
at com.opensymphony.xwork2.DefaultActionInvocation.executeResult(DefaultActionInvocation.java:361)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:265)
at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)

at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:468)
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)


[解决办法]
既然out.write("{'msg':'"+StringUtil.chinaToUnicode("你安全退出了！")+"'}");
就不需要 return SUCCESS;
直接return null就行了
[解决办法]
ActionContext.getContext().getSession().clear();
楼主为什么写这句呢？
[解决办法]
response已经将数据发送到客户端了，同时必须发送一个sessionid给客户端，但sesson已经被清空了，所以就无法发送Sessionid 了。你把“ActionContext.getContext().getSession().clear();”这句去掉看看
[解决办法]
觉得6楼分析的有道理