Question

我正在编写一个Java应用程序，以从浏览器上传文件。我正在使用9.4.15码头和Java servlet。上传文件时，出现以下错误消息。

java.lang.IllegalStateException: No multipart config for servlet
at org.eclipse.jetty.server.Request.getParts(Request.java:2342)
at org.eclipse.jetty.server.Request.getParts(Request.java:2330)
at org.eclipse.jetty.server.Request.getPart(Request.java:2318)
at com.RekognizeServlet.doPost(RekognizeServlet.java:47)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:754)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:873)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:542)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:205)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
at org.eclipse.jetty.server.Server.handle(Server.java:502)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:370)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:267)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce(EatWhatYouKill.java:132)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)
at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)
at java.lang.Thread.run(Thread.java:745)

下面是我编写的代码

SimplestServer.java

package com;

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletHandler;


public class SimplestServer
{
    public static void main(String[] args) throws Exception
    {
    Server server = new Server(8080);

    ServletHandler handler = new ServletHandler();
    server.setHandler(handler);
    handler.addServletWithMapping(RekognizeServlet.class, "/tryAndRecognize");
    server.start();
    server.join();
}
}

RekognizeServlet.java

package com;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Collection;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;

@MultipartConfig
public class RekognizeServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

public RekognizeServlet() {
    super();
}

protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html");
    response.setStatus(HttpServletResponse.SC_OK);
    response.getWriter().println("<!DOCTYPE html><html lang=\"en\"><head><title>File Upload</title><meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"></head><body><form method=\"POST\" action=\"tryAndRecognize\" enctype=\"multipart/form-data\" >File:<input type=\"file\" name=\"file\" id=\"file\" /> <br/></br><input type=\"submit\" value=\"Upload\" name=\"upload\" id=\"upload\" /></form></body></html>");
}

protected void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html;charset=UTF-8");

    // Create path components to save the file
    final String path = "/path/";
    final Part filePart = request.getPart("file");
    final Collection<Part> fileParts = request.getParts();
    final String fileName = getFileName(filePart);

    OutputStream out = null;
    InputStream filecontent = null;
    final PrintWriter writer = response.getWriter();

    try {
        out = new FileOutputStream(new File(path + File.separator + fileName));
        filecontent = filePart.getInputStream();

        int read = 0;
        final byte[] bytes = new byte[1024];

        while ((read = filecontent.read(bytes)) != -1) {
            out.write(bytes, 0, read);
        }
        System.out.println("File being uploaded to {1}");
    } catch (FileNotFoundException fne) {
        writer.println("You either did not specify a file to upload or are "
                + "trying to upload a file to a protected or nonexistent " + "location.");
        writer.println("<br/> ERROR: " + fne.getMessage());

        System.out.println("Problems during file upload");
        fne.printStackTrace();
    } finally {
        if (out != null) {
            out.close();
        }
        if (filecontent != null) {
            filecontent.close();
        }
        if (writer != null) {
            writer.close();
        }
    }
}

private String getFileName(final Part part) {
    final String partHeader = part.getHeader("content-disposition");
    System.out.println("Part Header = " + partHeader);
    for (String content : part.getHeader("content-disposition").split(";")) {
        if (content.trim().startsWith("filename")) {
            return content.substring(content.indexOf('=') + 1).trim().replace("\"", "");
        }
    }
    return null;
}

}

我没有像许多在线示例一样使用Handler。有人可以帮忙吗？

下面是我看到的链接（不是全部）

How to implement FileUpload in embedded Jetty?

https://github.com/eclipse/jetty.project/issues/240

Answer 1

由于您使用的是Embedded Jetty，因此默认情况下未启用字节码扫描注释（例如public class HiddenIterator { private final Set<Integer> set = new HashSet<Integer>(); public synchronized void add(Integer i) { set.add(i); } public synchronized void remove(Integer i) { set.remove(i); } public void addTenThings() { Random r = new Random(); for (int i = 0; i < 10; i++) add(r.nextInt()); synchronized(this) { System.out.println("DEBUG: added ten elements to " + set); } } }）。

启用字节码扫描需要大量的工作，实际上只需在代码中指定注释的实际作用即可。

因此，在您的情况下，只需更改Servlet即可。

示例：

@MultipartConfig

重要的是要注意MultipartConfig需要在指定的位置（最低限度）。另外，没有Server server = new Server(8080); ServletContextHandler context = new ServletContextHandler(); context.setContextPath("/"); ServletHolder uploadHolder = context.addServlet(RekognizeServlet.class, "/tryAndRecognize"); File tmpDir = new File(System.getProperty("java.io.tmpdir")); File locationDir = new File(tmpDir, "jetty-fileupload"); if (!locationDir.exists()) locationDir.mkdirs(); String location = locationDir.getAbsolutePath(); long maxFileSize = 1024 * 1024 * 50; long maxRequestSize = -1L; int fileSizeThreshold = 1024 * 1024; MultipartConfigElement multipartConfig = new MultipartConfigElement(location, maxFileSize, maxRequestSize, fileSizeThreshold); uploadHolder.getRegistration().setMultipartConfig(multipartConfig); server.setHandler(context); server.start();为您提供的ServletContext，MultipartConfig将无法工作。

使用码头和servlet上传文件

1 个答案: