Apache Camel - 多部分文件上传

Question

使用 Apache-Camel ESB，尝试将 xlsx 文件上传到 Spring Rest Web 应用程序。从 apache-camel ESB 上传失败。但是从邮递员上传工作正常。下面共享代码片段。

骆驼路由器中的处理器代码看起来像

    from("file://data/PASInput").process(new Processor() {
    @Override
    public void process(Exchange exchange) throws Exception {

        MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
        multipartEntityBuilder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        String filename = (String) exchange.getIn().getHeader(Exchange.FILE_NAME);
        File file = exchange.getIn().getBody(File.class);
        multipartEntityBuilder.addPart("file",
            new FileBody(file, ContentType.MULTIPART_FORM_DATA, filename));
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        multipartEntityBuilder.build().writeTo(out);
        InputStream  inputStream = new ByteArrayInputStream(out.toByteArray());
        exchange.getOut().setBody(inputStream);         
    }
}).to("http://localhost:8080/Pastel/api/convertor/pas/pastel")
        .log(LoggingLevel.ERROR, "RESPONSE BODY ${body}").end();

Pom.xml

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-spring-boot-starter</artifactId>
        <version>2.21.0.fuse-000077-redhat-1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-cxf</artifactId>
        <version>2.21.0.fuse-000077-redhat-1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpmime</artifactId>
        <version>4.3.1</version>
    </dependency>
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-http</artifactId>
        <version>2.21.0.fuse-000077-redhat-1</version>
    </dependency>       
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-http4</artifactId>
        <version>2.17.2</version>
    </dependency>

错误

    org.apache.camel.http.common.HttpOperationFailedException: HTTP operation failed invoking http://localhost:8080/Pastel/api/convertor/pas/pastel with statusCode: 500
    at org.apache.camel.component.http.HttpProducer.populateHttpOperationFailedException(HttpProducer.java:274)
   at org.apache.camel.component.http.HttpProducer.process(HttpProducer.java:183)
   at org.apache.camel.util.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:61)
   at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:148)
   at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:548)
   at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201)
   at org.apache.camel.processor.Pipeline.process(Pipeline.java:138)
   at org.apache.camel.processor.Pipeline.process(Pipeline.java:101)
   at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201)
   at org.apache.camel.component.file.GenericFileConsumer.processExchange(GenericFileConsumer.java:452)
   at org.apache.camel.component.file.GenericFileConsumer.processBatch(GenericFileConsumer.java:219)
   at org.apache.camel.component.file.GenericFileConsumer.poll(GenericFileConsumer.java:183)
   at org.apache.camel.impl.ScheduledPollConsumer.doRun(ScheduledPollConsumer.java:174)
   at org.apache.camel.impl.ScheduledPollConsumer.run(ScheduledPollConsumer.java:101)
   at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)

当我们使用邮递员访问网络服务时，没有错误。能够成功上传服务器。 Spring mvc 代码，

            @RequestMapping(value = "/pas/pastel", method = RequestMethod.POST)
            @ResponseBody
            public void convertPASToPastel(HttpServletRequest request, HttpServletResponse response,
            @RequestParam(value = "file") final MultipartFile pasFile) {
               try {
                  System.out.print("Here");
               }
            }

Answer 1

您可能会在 Spring 后端日志中看到此错误消息：

org.springframework.web.multipart.MultipartException: Current request is not a multipart request.

您需要设置正确的 ContentType header。如果您想以这种方式实现，请参考this 类似问题的解决方案。

但是如果你切换 co camel-http4 组件（你已经在 pom.xml 中有这个组件），你可以解决这个问题。该组件包含将 HttpEntity 转换为 InputStream 的逻辑。那么就可以直接设置HttpEntity来交换body.

那么您的路线将如下所示：

from("file://data/PASInput").process(new Processor() {
    @Override
    public void process(Exchange exchange) throws Exception {
        MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
        multipartEntityBuilder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        String filename = exchange.getIn().getHeader(Exchange.FILE_NAME, String.class);
        File file = exchange.getIn().getBody(File.class);
        multipartEntityBuilder.addPart("file",
                new FileBody(file, ContentType.MULTIPART_FORM_DATA, filename));
        exchange.getOut().setBody(multipartEntityBuilder.build());
    }
}).to("http4://localhost:8080/Pastel/api/convertor/pas/pastel")
        .log(LoggingLevel.ERROR, "RESPONSE BODY ${body}").end();

还有一张纸条。 切勿混用组件版本，始终使用与 Apache Camel 版本相同的组件。否则你会看到不可预测的结果。为什么在 Spring 控制器中有注解 @ResponseBody，而方法是 void？你不需要那个。

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