java - 如何修复从网页获取报告时抛出的 IllegalStateException

Question

这个问题已经有答案了:

Spring: getOutputStream() has already been called for this response (3 个回答)

已关闭 4 年前。

我正在尝试从网页获取报告。实际上报告已按预期生成，并且可以正确下载。但我在调试时在控制台中收到 IllegalStateException 。堆栈跟踪引用了我的方法之一，称为“AddResponseHeaderFilter.doFilter()”。该方法仅设置字符集UTF-8，并且该类实现javax.servlet.Filter。

我使用的技术:业务逻辑:Java(Spring)、报表引擎:JasperReports，应用服务器:Tomcat9

@Override 
public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        chain.doFilter(request, response);
    }

堆栈跟踪

java.lang.IllegalStateException: getOutputStream() has already been called for this response
    at org.apache.catalina.connector.Response.getWriter(Response.java:582) ~[catalina.jar:9.0.20]
    at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:227) ~[catalina.jar:9.0.20]
    at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:114) ~[servlet-api.jar:4.0.FR]
    at org.springframework.boot.web.servlet.support.ErrorPageFilter$ErrorWrapperResponse.getWriter(ErrorPageFilter.java:374) ~[spring-boot-2.2.0.M2.jar:2.2.0.M2]
    at org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:360) ~[thymeleaf-spring5-3.0.11.RELEASE.jar:3.0.11.RELEASE]
    at org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:189) ~[thymeleaf-spring5-3.0.11.RELEASE.jar:3.0.11.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1370) ~[spring-webmvc-5.2.0.M1.jar:5.2.0.M1]
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1116) ~[spring-webmvc-5.2.0.M1.jar:5.2.0.M1]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1055) ~[spring-webmvc-5.2.0.M1.jar:5.2.0.M1]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942) ~[spring-webmvc-5.2.0.M1.jar:5.2.0.M1]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005) ~[spring-webmvc-5.2.0.M1.jar:5.2.0.M1]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897) ~[spring-webmvc-5.2.0.M1.jar:5.2.0.M1]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634) ~[servlet-api.jar:na]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882) ~[spring-webmvc-5.2.0.M1.jar:5.2.0.M1]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[servlet-api.jar:na]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[catalina.jar:9.0.20]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-websocket.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[catalina.jar:9.0.20]
    at org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:109) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[catalina.jar:9.0.20]
    at com.beybo.filters.AddResponseHeaderFilter.doFilter(AddResponseHeaderFilter.java:33) ~[classes/:na]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[catalina.jar:9.0.20]
    at org.springframework.boot.web.servlet.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:130) ~[spring-boot-2.2.0.M2.jar:2.2.0.M2]
    at org.springframework.boot.web.servlet.support.ErrorPageFilter.access$000(ErrorPageFilter.java:66) ~[spring-boot-2.2.0.M2.jar:2.2.0.M2]
    at org.springframework.boot.web.servlet.support.ErrorPageFilter$1.doFilterInternal(ErrorPageFilter.java:105) ~[spring-boot-2.2.0.M2.jar:2.2.0.M2]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.2.0.M1.jar:5.2.0.M1]
    at org.springframework.boot.web.servlet.support.ErrorPageFilter.doFilter(ErrorPageFilter.java:123) ~[spring-boot-2.2.0.M2.jar:2.2.0.M2]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[catalina.jar:9.0.20]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200) ~[spring-web-5.2.0.M1.jar:5.2.0.M1]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-5.2.0.M1.jar:5.2.0.M1]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[catalina.jar:9.0.20]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[catalina.jar:9.0.20]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[catalina.jar:9.0.20]
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678) ~[catalina.jar:9.0.20]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[catalina.jar:9.0.20]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[catalina.jar:9.0.20]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408) ~[tomcat-coyote.jar:9.0.20]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) ~[tomcat-coyote.jar:9.0.20]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836) ~[tomcat-coyote.jar:9.0.20]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1839) ~[tomcat-coyote.jar:9.0.20]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-coyote.jar:9.0.20]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-util.jar:9.0.20]
    at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]

代码

@Controller 
@RequestMapping("/report") 
public class RaporController { 

    @GetMapping() String reporting(Model model, HttpServletResponse response) throws IOException { 
        JasperPrint jasperPrint = reportService.report(new Date(), sqlTable, false); 
        response.setContentType("application/pdf");
        response.setHeader("Content-Disposition", String.format("attachment; filename=\"" + reportService.getFilename() + "\""));
        OutputStream out = response.getOutputStream();
        JasperExportManager.exportReportToPdfStream(jasperPrint, out);
        return "home"; 
     }
}

Answer 1

您正在混合 PDF 的下载和 Thymeleaf 的渲染。

相反，您应该返回一个带有包含 PDF 的 byte[] 的 ResponseEntity:

@Controller 
@RequestMapping("/report") 
public class RaporController { 

    @GetMapping() 
    public ResponseEntity reporting(Model model, HttpServletResponse response) throws IOException { 
        JasperPrint jasperPrint = reportService.report(new Date(), sqlTable, false); 
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        JasperExportManager.exportReportToPdfStream(jasperPrint, out);

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_PDF);
        headers.setContentDispositionFormData(reportService.getFilename(), reportService.getFilename());
        headers.setCacheControl("must-revalidate, post-check=0, pre-check=0");

        return new ResponseEntity(out.toByteArray(), headers, HttpStatus.OK);
     }
}