Apache camel servlet流在split（）后关闭

Question

我需要发布一个JSON Camel Servlet，然后复制消息并拆分列表。处理每个拆分的消息，最后聚合并返回servlet响应。

然而，只要在路由中引入拆分器，我就会看到输入流正在关闭，Servlet无法写回响应。

请注意，流缓存也已启用。

from("servlet:sample")
                .log(LoggingLevel.INFO, "Message Received: JSON RQ")
                .to("direct:samplejson");
from("direct:samplejson")
    .streamCaching()
    .setHeader("sampleId", simple("${id}"))
    .log(LoggingLevel.INFO, SampleID in Header: ${header.sampleId}")
    .unmarshal().json(JsonLibrary.Jackson, Sample.class)
    .log(LoggingLevel.INFO, "Converted to JSON: ${body.toString}")
    .process("sampleProcessor")
    .split().body().streaming()
        .choice()
        .when().method("sampleProcessor", "isTypeA")
            .marshal().jacksonxml(Sample.class)
        .endChoice()
        .otherwise()
            .marshal().jacksonxml(Sample.class)
    .end()
    .aggregate(SampleAggregationStrategy).header("sampleId").completionSize(2).completionTimeout(1000L)
    .to("direct:samplexml");
from("direct:samplexml").marshal().jacksonxml(List.class).log("FINISHED PROCESSING");

例外：

2017-06-12 12:22:25,311 [apr-8080-exec-2] INFO  route1                         - FINISHED PROCESSING
2017-06-12 12:22:25,321 [apr-8080-exec-2] ERROR CamelHttpTransportServlet      - Error processing request
java.io.IOException: Stream closed
        at org.apache.catalina.connector.InputBuffer.read(InputBuffer.java:372) ~[catalina.jar:8.0.30]
        at org.apache.catalina.connector.CoyoteInputStream.read(CoyoteInputStream.java:156) ~[catalina.jar:8.0.30]
        at org.apache.camel.util.IOHelper.copy(IOHelper.java:196) ~[camel-core-2.19.0.jar:2.19.0]
        at org.apache.camel.http.common.DefaultHttpBinding.copyStream(DefaultHttpBinding.java:432) ~[camel-http-common-2.19.0.jar:2.19.0]
        at org.apache.camel.http.common.DefaultHttpBinding.doWriteDirectResponse(DefaultHttpBinding.java:496) ~[camel-http-common-2.19.0.jar:2.19.0]
        at org.apache.camel.http.common.DefaultHttpBinding.doWriteResponse(DefaultHttpBinding.java:395) ~[camel-http-common-2.19.0.jar:2.19.0]
        at org.apache.camel.http.common.DefaultHttpBinding.writeResponse(DefaultHttpBinding.java:322) ~[camel-http-common-2.19.0.jar:2.19.0]
        at org.apache.camel.http.common.CamelServlet.doService(CamelServlet.java:210) [camel-http-common-2.19.0.jar:2.19.0]
        at org.apache.camel.http.common.CamelServlet.service(CamelServlet.java:74) [camel-http-common-2.19.0.jar:2.19.0]
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:729) [servlet-api.jar:?]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291) [catalina.jar:8.0.30]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.30]
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) [tomcat-websocket.jar:8.0.30]
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239) [catalina.jar:8.0.30]
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) [catalina.jar:8.0.30]
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212) [catalina.jar:8.0.30]
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106) [catalina.jar:8.0.30]
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) [catalina.jar:8.0.30]
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141) [catalina.jar:8.0.30]
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) [catalina.jar:8.0.30]
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616) [catalina.jar:8.0.30]
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) [catalina.jar:8.0.30]
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:521) [catalina.jar:8.0.30]
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1096) [tomcat-coyote.jar:8.0.30]
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:674) [tomcat-coyote.jar:8.0.30]
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2500) [tomcat-coyote.jar:8.0.30]
        at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2489) [tomcat-coyote.jar:8.0.30]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_74]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_74]
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-util.jar:8.0.30]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_74]

如果我删除拆分器和聚合器，我会看到Servlet响应回来。

非常感谢您提供的所有帮助！。

Answer 1

请参阅堆肥消息处理器EIP模式（http://camel.apache.org/composed-message-processor.html）和仅使用拆分器的示例，它允许您在同一工作单元中进行分叉/连接，并能够在servlet中返回响应。拆分器仅支持AggregationStrategy您可以配置聚合响应的位置。换句话说，不要同时使用拆分器和聚合器，而只使用拆分器。