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spring-boot - 未找到类型返回值的转换器：类 java.io.ByteArrayOutputStream

问题描述

我正在尝试通过 Postman 访问我的 api，它在 ByteArrayOutputStream 中返回响应。但它在邮递员中给出错误，如下所示。

我的api，

 @GetMapping(value = "/excelsheet")
    public ResponseEntity<ByteArrayOutputStream> downloadExcel() throws IOException {
        ByteArrayOutputStream out =departmentService.executeGridObjectListDemo();
        System.out.println(out);
        HttpHeaders headers = new HttpHeaders();
        headers.add("Content-Disposition", "attachment; filename=department.xlsx");

        return ResponseEntity
                .ok()
                .headers(headers)
                .body(out);

    }

如何通过邮递员访问此 api？

我收到此错误，

"timestamp": "2019-08-11T10:22:54.603+0000",
    "status": 500,
    "error": "Internal Server Error",
    "message": "No converter found for return value of type: class java.io.ByteArrayOutputStream",
    "trace": "org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class java.io.ByteArrayOutputStream\n\tat org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:233)\n\tat org.springframework.web.servlet.mvc.method.annotation.HttpEntityMethodProcessor.handleReturnValue(HttpEntityMethodProcessor.java:225)\n\tat org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:82)\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:122)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892)\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039)\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)\n\tat org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:897)\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:634)\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:741)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:88)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:114)\n\tat org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:104)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:853)\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587)\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\n\tat java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)\n\tat java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\n\tat java.lang.Thread.run(Thread.java:748)\n",
    "path": "/api/department/excelsheet"
}

标签： spring-bootpostmanbytearrayoutputstream

解决方案

您的问题有 2 个解决方案。首先，您将流写入 HttpServletResponse 或者您可以将文件读入 inputStream 并将 inputStream 写入 InputStreamResource 并返回它。

第一的：

    @GetMapping(value = "/excelsheet")
    @ResponseBody
    downloadExcel(HttpServletResponse response) throws IOException {
         ...
         ByteArrayOutputStream out = departmentService.executeGridObjectListDemo();
         ...
         try {
                OutputStream outputStream = response.getOutputStream();
                out.writeTo(outputStream);
                outputStream.close();
                // second close can be put in a separate try-catch
                out.close();
         } catch (IOException e) {

         }
         ...
     }

第二：

org.springframework.core.io.Resource resource = new InputStreamResource(inputStream);
return new ResponseEntity<>(resource, headers, HttpStatus.OK);

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