java - Illegalstateexception: getwriter() 已经被调用了这个响应

Question

我正在尝试使用以下代码片段在浏览器中打开 pdf 文件：

    public ActionResult action(Request request, AspectModel arg1)
        throws ServletException {
    if ("PDF".equals(request.event())) {
    try{
    HttpServletResponse resp=(HttpServletResponse) request.getResponse();
    resp.setContentType("application/pdf");
    resp.setHeader("Content-Disposition","inline;filename=AccountOpeningSummary.pdf");
    resp.setHeader("Cache-Control", "cache, must-revalidate");
    resp.setHeader("Cache-Control", "no-store,public");
    resp.setDateHeader("Expires", 0);
    resp.setHeader("Pragma", "public");
    OutputStream OutStream = resp.getOutputStream();
    OutStream.write(infos,0,infos.length);
    OutStream.flush();        
    OutStream.close(); 
    }catch (Exception e) {
        System.out.println("PDF Write Exception...........................####"+e);
    }
    }
    return null;
}

我收到以下错误：

java.lang.IllegalStateException: getOutputStream() has already been called for this response
    at org.apache.catalina.connector.Response.getWriter(Response.java:626)
    at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:215)
    at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:105)
    at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:125)
    at org.apache.jasper.runtime.JspWriterImpl.flushBuffer(JspWriterImpl.java:118)
    at org.apache.jasper.runtime.JspWriterImpl.flush(JspWriterImpl.java:177)
    at abaxx.web.taglib.IncludeTag.doEndTag(IncludeTag.java:69)
    at org.apache.jsp.parts.index_jsp._jspx_meth_xx_005finclude_005f0(index_jsp.java:237)
    at org.apache.jsp.parts.index_jsp._jspService(index_jsp.java:93)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:593)
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:530)
    at abaxx.core.foundation.internal.SelfDestroyingHttpServletRequestWrapper$1.include(SelfDestroyingHttpServletRequestWrapper.java:36)
    at abaxx.core.foundation.internal.SelfDestroyingHttpServletRequestWrapper$1.include(SelfDestroyingHttpServletRequestWrapper.java:36)
    at abaxx.web.parts.internal.ServletRequestContext.doInclude(ServletRequestContext.java:85)
    at abaxx.web.parts.RequestContext.include(RequestContext.java:429)
    at abaxx.web.parts.VisualPart.basicDisplay(VisualPart.java:740)
    at abaxx.web.parts.CompositePart.basicDisplay(CompositePart.java:111)
    at abaxx.web.parts.VisualPart.doDisplay(VisualPart.java:762)
    at abaxx.web.control.DisplayLoopInterceptor.display(DisplayLoopInterceptor.java:233)
    at abaxx.web.security.StandardSecurityPolicy$DisplayHook.display(StandardSecurityPolicy.java:321)
    at abaxx.web.control.PerformanceMonitor$DisplayPerformanceInterceptor.display(PerformanceMonitor.java:187)
    at abaxx.web.control.DisplayLoopInterceptor.doDisplay(DisplayLoopInterceptor.java:80)
    at abaxx.web.parts.VisualPart.display(VisualPart.java:104)
    at abaxx.web.control.DisplayLoopInterceptor.process(DisplayLoopInterceptor.java:128)
    at vanilla.portal.builder.PBDisplayLoopInterceptor.process(PBDisplayLoopInterceptor.java:60)
    at vanilla.common.EncodingExtension$ResponseEncodingInterceptor.process(EncodingExtension.java:107)
    at abaxx.web.preferences.PreferencesHookup$2.process(PreferencesHookup.java:126)
    at vanilla.common.HttpHeaderInterceptor.process(HttpHeaderInterceptor.java:36)
    at abaxx.web.control.PageflowInterceptor.process(PageflowInterceptor.java:62)
    at abaxx.workflow.pageflow.PageflowInterceptor.process(PageflowInterceptor.java:93)
    at abaxx.web.control.ActionInterceptor.process(ActionInterceptor.java:49)
    at abaxx.web.security.StandardSecurityPolicy$ActionHook.process(StandardSecurityPolicy.java:211)
    at abaxx.web.control.SessionTimeoutInterceptor.process(SessionTimeoutInterceptor.java:59)
    at abaxx.track.TrackingInterceptor.finishTracking(TrackingInterceptor.java:151)
    at abaxx.track.TrackingInterceptor.process(TrackingInterceptor.java:100)
    at abaxx.web.control.AccessViolationInterceptor.process(AccessViolationInterceptor.java:110)
    at abaxx.web.control.RequestProcessor$P9.process(RequestProcessor.java:72)
    at abaxx.web.control.PerformanceMonitor$RequestPerformanceInterceptor.process(PerformanceMonitor.java:153)
    at vanilla.common.EncodingExtension$RequestEncodingInterceptor.process(EncodingExtension.java:61)
    at abaxx.web.control.MaintenanceInterceptor.process(MaintenanceInterceptor.java:44)
    at abaxx.web.control.AbaXXComponentsHookup$ClientSessionHookupInterceptor.process(AbaXXComponentsHookup.java:42)
    at abaxx.web.security.SecurityPolicy$FakeContainerLoginInterceptor.process(SecurityPolicy.java:136)
    at abaxx.web.control.RequestProcessor.process(RequestProcessor.java:187)
    at abaxx.web.control.ApplicationServlet.doGet(ApplicationServlet.java:144)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at abaxx.web.control.url.RequestFilter.doFilter(RequestFilter.java:28)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at abaxx.web.control.CachingHeaderFilter.doFilter(CachingHeaderFilter.java:29)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at vanilla.common.EncodingExtension.doFilter(EncodingExtension.java:121)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:563)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:403)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:301)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:162)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:619)

我也尝试过关闭getWriter() 使用：

HttpServletResponse resp=(HttpServletResponse) request.getResponse();
Writer rt=resp.getWriter();
resp.getWriter().close();

谁能帮我？

score 3 · Accepted Answer

编辑：现在问题已经发生了显着变化......

听起来 JSP 仍在尝试将自己呈现为响应。您需要告诉容器您正在处理请求 - 理想情况下，您不应该靠近 JSP，因为这可能只是针对 PDF 的请求。您应该将容器配置为调用单独的 servlet 来下载 PDF；这样你就不会涉及到 JSP 部分。

（是的，这将意味着移动您在问题中显示的代码。这可能是当前 JSP 的一部分；它不应该是。）

score 2 · Accepted Answer

那是因为您已将使用响应输出流的 PDF 生成代码放在 JSP 文件中<jsp:include>。JSP 文件隐式使用响应编写器，因为 JSP 文件旨在生成基于字符的 HTML 代码（而不是像 PDF 文件那样基于二进制）。JSP 首先是放置 PDF 生成代码的错误位置。HTML 和 PDF 不能很好地混合。

要解决您的设计问题，您需要创建一个简单的类扩展HttpServlet，将所有 Java 代码移动到doGet()方法中（或者doPost()，取决于您想要响应的请求类型）。@WebServlet最后，通过注释或<servlet-mapping>in将该 servlet 映射到所需的 URL 模式，web.xml并将 PDF 请求的 URL 从 JSP 一更改为 servlet 一。

这是一个基本的启动示例，假设您使用的是与 Servlet 3.0 兼容的容器，例如 Tomcat 7、Glassfish 3 等，以便您可以使用@WebServlet注释：

@WebServlet("/pdfServlet")
public class HelloServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // Put your code here.
    }

}

http://localhost:8080/contextname/pdfServlet通过而不是调用它index.jsp。

如果您的要求毕竟是在 HTML 页面中显示 PDF 内联，那么您需要<iframe>而不是<jsp:include>. 例如

<iframe src="pdfServlet"></iframe>

这样，浏览器将通过一个完全独立的 HTTP 请求下载 PDF 文件。

score 1 · Accepted Answer

你用的是哪个版本的abaxx？在最近的版本中，如果您在控制器中生成响应，则可以从操作方法返回 ActionResult.ABORT。如果您返回 null，则框架将进入显示阶段并呈现 JSP。

java - Illegalstateexception: getwriter() 已经被调用了这个响应

3 回答 3

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