Java vertx 3.2 使用bodyhandler上传文件

Question

java.lang.IllegalStateException: vertx3.0 中请求已被读取异常。我尝试了很多方法。简单的表单上传工作正常。但是当我使用主体处理程序时，它抛出以下异常。有人可以帮忙吗？

import io.vertx.core.AbstractVerticle;
import io.vertx.core.http.HttpHeaders;

import io.vertx.ext.web.Router;
import io.vertx.ext.web.handler.BodyHandler;

/*
 * @author Gogs
 */

public class TestServer extends AbstractVerticle {

  // Convenience method so you can run it in your IDE
  public static void main(String[] args) {
    Runner.runExample(TestServer.class);
  }

  @Override
  public void start() throws Exception {

    Router router = Router.router(vertx);

    // Enable multipart form data parsing
    router.route().handler(BodyHandler.create());

    router.route("/").handler(routingContext -> {
      routingContext.response().putHeader("content-type", "text/html").end(
          "<form action=\"/form\" ENCTYPE=\"multipart/form-data\" method=\"POST\" name=\"wibble\">\n" +
           "choose a file to upload:<input type=\"file\" name=\"myfile\"/><br>"+
          " <input type=\"submit\"/>"+
          "</form>"
      );
    });

    // handle the form
    router.post("/form").handler(ctx -> {

      ctx.request().setExpectMultipart(true);
      ctx.request().uploadHandler(upload -> {
          upload.exceptionHandler(cause -> {
            ctx.response().setChunked(true).end("Upload failed");
          });

          upload.endHandler(v -> {
            ctx.response().setChunked(true).end("Successfully uploaded to " + upload.filename());
          });
          // FIXME - Potential security exploit! In a real system you must check this filename
          // to make sure you're not saving to a place where you don't want!
          // Or better still, just use Vert.x-Web which controls the upload area.
          upload.streamToFileSystem(upload.filename());
        });


    });

    vertx.createHttpServer().requestHandler(router::accept).listen(8090);
  }
}

Am seeing the below exception.


Feb 02, 2016 6:48:54 PM io.vertx.ext.web.impl.RoutingContextImplBase

SEVERE: Unexpected exception in route

java.lang.IllegalStateException: Request has already been read

    at io.vertx.core.http.impl.HttpServerRequestImpl.checkEnded(HttpServerRequestImpl.java:426)
    at io.vertx.core.http.impl.HttpServerRequestImpl.setExpectMultipart(HttpServerRequestImpl.java:322)
    at io.vertx.ext.web.impl.HttpServerRequestWrapper.setExpectMultipart(HttpServerRequestWrapper.java:166)
    at com.vertx.http.upload.TestServer.lambda$1(TestServer.java:43)
    at io.vertx.ext.web.impl.RouteImpl.handleContext(RouteImpl.java:221)
    at io.vertx.ext.web.impl.RoutingContextImplBase.iterateNext(RoutingContextImplBase.java:78)
    at io.vertx.ext.web.impl.RoutingContextImpl.next(RoutingContextImpl.java:93)
    at io.vertx.ext.web.handler.impl.BodyHandlerImpl$BHandler.doEnd(BodyHandlerImpl.java:155)
    at io.vertx.ext.web.handler.impl.BodyHandlerImpl$BHandler.uploadEnded(BodyHandlerImpl.java:135)
    at io.vertx.ext.web.handler.impl.BodyHandlerImpl$BHandler.lambda$null$35(BodyHandlerImpl.java:109)
    at io.vertx.core.http.impl.HttpServerFileUploadImpl.notifyEndHandler(HttpServerFileUploadImpl.java:213)
    at io.vertx.core.http.impl.HttpServerFileUploadImpl.lambda$handleComplete$165(HttpServerFileUploadImpl.java:206)
    at io.vertx.core.file.impl.AsyncFileImpl.lambda$doClose$226(AsyncFileImpl.java:470)
    at io.vertx.core.impl.ContextImpl.lambda$wrapTask$16(ContextImpl.java:335)
    at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:358)
    at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:357)
    at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:112)
    at java.lang.Thread.run(Unknown Source)

Answer 1

您正在阅读请求正文两次。第一次读取是通过 BodyHandler (请参阅 BodyHanderImpl)，第二次读取是通过您自己的处理程序(请参阅 HttpServerRequestImpl 和 HttpServerFileUploadImpl) >).

BodyHandler 从请求中完全读取正文并使其在 context.body 中可用。路由器的配置方式:

router.route().handler(BodyHandler.create());

将在路由器处理的每个请求上完整读取正文。

您的处理程序还完整读取请求正文并将其内容写入文件系统。您的路由器配置为仅在对 /form 进行 POST 时执行处理程序。

回顾一下流程，当您将上传提交到 /form 时，BodyHandler 正在完全读取请求，将内容存储在 context.body 中，并标记请求正文如所读。您的路由器将 uri 路径与您的上传处理程序相匹配，并尝试再次读取正文，但由于它已经被读取，因此会引发异常。

一些想法...

如果您的目的是将上传的文件写入文件系统，您实际上不需要在路由器中配置 BodyHandler。当您需要内存中的主体以便以某种方式处理它时，您可能需要使用 BodyHandler。除非您打算对路由器收到的单个请求执行处理程序，否则不应在没有匹配条件的情况下配置处理程序(即 router.route().handler(...))。这种类型的处理程序的一个很好的用例是 CookieHandler。