java - jetty ， "No multipart config for servlet"问题

Question

我正在编写文件传输处理程序。该请求是多部分 HTTP 消息。该消息是正确的 - 在其他服务器上测试过。

问题是 getParts() 调用时出现“java.lang.IllegalStateException:No multipart config for servlet”。

测试代码:

@SuppressWarnings("serial")
@MultipartConfig
@WebServlet(urlPatterns={"/upload"}, name="upload")
public class FilesServlet extends HttpServlet
{
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
    {
        resp.setContentType("text/plain");
        PrintWriter out = resp.getWriter();

        int i=0;
        for(Part part: req.getParts())
        {
            out.printf("Got part: name=%s, size=%d%n",part.getName(), part.getSize());
            part.write(String.format("part-%02d.dat",i++));
        }
    }
}

异常(exception):

java.lang.IllegalStateException: No multipart config for servlet
    at org.eclipse.jetty.server.Request.getParts(Request.java:2327)
    at org.eclipse.jetty.server.Request.getParts(Request.java:2314)
    at com.rad.server.servlet.FilesServlet.doPost(FilesServlet.java:31)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:535)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:188)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle(Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce(EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:626)
    at java.lang.Thread.run(Thread.java:745)

这些 jar 是:jetty-server-9.4.8 和 javax-servlet-api-3.10。

这里出了什么问题？

Answer 1

实际上，我没有找到为什么 @MultipartConfig 注释对我不起作用，但我在 i-net 上找到了一种可以正常工作的解决方法:

     private static final MultipartConfigElement MULTI_PART_CONFIG = new MultipartConfigElement("c:/temp");
        ...
     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String contentType = request.getContentType();

        if(contentType != null && contentType.startsWith("multipart/")){
           request.setAttribute(Request.__MULTIPART_CONFIG_ELEMENT, MULTI_PART_CONFIG);
           for(Part part: request.getParts()) { ... } ;
        } else {  
            ...
        }          
      }

我认为这个解决方案对于遇到此类问题的开发人员可能有用