Cannot create a session after the response has been committed
MyEclipse,使用SSH框架，Action功能是从页面读入查询条件，在action中拼hql，将查询结果写入excel弹出下载

查询与Excel弹出下载均无问题

错误如下：

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:2301)
at org.apache.catalina.connector.Request.getSession(Request.java:2075)
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:545)
at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:494)
at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:224)
at org.apache.jasper.runtime.PageContextImpl._initialize(PageContextImpl.java:144)
at org.apache.jasper.runtime.PageContextImpl.initialize(PageContextImpl.java:122)
at org.apache.jasper.runtime.JspFactoryImpl.internalGetPageContext(JspFactoryImpl.java:107)
at org.apache.jasper.runtime.JspFactoryImpl.getPageContext(JspFactoryImpl.java:63)
at org.apache.jsp.index_jsp._jspService(index_jsp.java:55)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
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:654)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:557)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:481)
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 com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
at com.op