fileupload.java

java servlet著名论坛源代码

            MultipartStream multi = new MultipartStream(input, boundary);
            boolean nextPart = multi.skipPreamble();
            while (nextPart)
            {
                Map headers = parseHeaders(multi.readHeaders());
                String fieldName = getFieldName(headers);
                if (fieldName != null)
                {
                    String subContentType = getHeader(headers, CONTENT_TYPE);
                    if (subContentType != null && subContentType
                                                .startsWith(MULTIPART_MIXED))
                    {
                        // Multiple files.
                        byte[] subBoundary =
                            subContentType.substring(
                                subContentType
                                .indexOf("boundary=") + 9).getBytes();
                        multi.setBoundary(subBoundary);
                        boolean nextSubPart = multi.skipPreamble();
                        while (nextSubPart)
                        {
                            headers = parseHeaders(multi.readHeaders());
                            if (getFileName(headers) != null)
                            {
                                FileItem item =
                                    createItem(sizeThreshold, path,
                                               headers, requestSize);
                                OutputStream os =
                                    ((DefaultFileItem) item).getOutputStream();
                                try
                                {
                                    multi.readBodyData(os);
                                }
                                finally
                                {
                                    os.close();
                                }
                                item.setFieldName(getFieldName(headers));
                                items.add(item);
                            }
                            else
                            {
                                // Ignore anything but files inside
                                // multipart/mixed.
                                multi.discardBodyData();
                            }
                            nextSubPart = multi.readBoundary();
                        }
                        multi.setBoundary(boundary);
                    }
                    else
                    {
                        if (getFileName(headers) != null)
                        {
                            // A single file.
                            FileItem item = createItem(sizeThreshold,
                                                       path, headers,
                                                       requestSize);
                            OutputStream os =
                                ((DefaultFileItem) item).getOutputStream();
                            try
                            {
                                multi.readBodyData(os);
                            }
                            finally
                            {
                                os.close();
                            }
                            item.setFieldName(getFieldName(headers));
                            items.add(item);
                        }
                        else
                        {
                            // A form field.
                            FileItem item = createItem(sizeThreshold,
                                                       path, headers,
                                                       requestSize);
                            OutputStream os =
                                ((DefaultFileItem) item).getOutputStream();
                            try
                            {
                                multi.readBodyData(os);
                            }
                            finally
                            {
                                os.close();
                            }
                            item.setFieldName(getFieldName(headers));
                            item.setIsFormField(true);
                            items.add(item);
                        }
                    }
                }
                else
                {
                    // Skip this part.
                    multi.discardBodyData();
                }
                nextPart = multi.readBoundary();
            }
        }
        catch (IOException e)
        {
            throw new FileUploadException(
                "Processing of " + MULTIPART_FORM_DATA +
                    " request failed. " + e.getMessage());
        }

        return items;
    }


    // ------------------------------------------------------ Protected methods


    /**
     * Retrieves the file name from the <code>Content-disposition</code>
     * header.
     *
     * @param headers A <code>Map</code> containing the HTTP request headers.
     *
     * @return The file name for the current <code>encapsulation</code>.
     */
    protected String getFileName(Map /* String, String */ headers)
    {
        String fileName = null;
        String cd = getHeader(headers, CONTENT_DISPOSITION);
        if (cd.startsWith(FORM_DATA) || cd.startsWith(ATTACHMENT))
        {
            int start = cd.indexOf("filename=\"");
            int end = cd.indexOf('"', start + 10);
            if (start != -1 && end != -1)
            {
                fileName = cd.substring(start + 10, end).trim();
            }
        }
        return fileName;
    }


    /**
     * Retrieves the field name from the <code>Content-disposition</code>
     * header.
     *
     * @param headers A <code>Map</code> containing the HTTP request headers.
     *
     * @return The field name for the current <code>encapsulation</code>.
     */
    protected String getFieldName(Map /* String, String */ headers)
    {
        String fieldName = null;
        String cd = getHeader(headers, CONTENT_DISPOSITION);
        if (cd != null && cd.startsWith(FORM_DATA))
        {
            int start = cd.indexOf("name=\"");
            int end = cd.indexOf('"', start + 6);
            if (start != -1 && end != -1)
            {
                fieldName = cd.substring(start + 6, end);
            }
        }
        return fieldName;
    }


    /**
     * Creates a new {@link net.myvietnam.mvncore.fileupload.FileItem} instance.
     *
     * @param sizeThreshold The max size in bytes to be stored in memory.
     * @param path          The path for the FileItem.
     * @param headers       A <code>Map</code> containing the HTTP request
     *                      headers.
     * @param requestSize   The total size of the request, in bytes.
     *
     * @return A newly created <code>FileItem</code> instance.
     *
     * @exception FileUploadException if an error occurs.
     */
    protected FileItem createItem(int sizeThreshold,
                                  String path,
                                  Map /* String, String */ headers,
                                  int requestSize)
        throws FileUploadException
    {
        Method newInstanceMethod = getNewInstanceMethod();
        Object[] args = new Object[] {
                path, getFileName(headers), getHeader(headers, CONTENT_TYPE),
                new Integer(requestSize), new Integer(sizeThreshold) };
        FileItem fileItem = null;

        try
        {
            fileItem = (FileItem) newInstanceMethod.invoke(null, args);
        }
        catch (Exception e)
        {
            throw new FileUploadException(e.toString());
        }

        return fileItem;
    }


    /**
     * <p> Returns the <code>Method</code> object to be used to obtain a new
     * <code>FileItem</code> instance.
     *
     * <p> For performance reasons, we cache the method once it has been
     * looked up, since method lookup is one of the more expensive aspects
     * of reflection.
     *
     * @return The <code>newInstance()</code> method to be invoked.
     *
     * @exception FileUploadException if an error occurs.
     */
    protected Method getNewInstanceMethod()
        throws FileUploadException
    {
        // If the method is already cached, just return it.
        if (this.newInstanceMethod != null)
        {
            return this.newInstanceMethod;
        }

        // Load the FileUpload implementation class.
        ClassLoader classLoader =
                Thread.currentThread().getContextClassLoader();
        Class fileItemClass = null;

        if (classLoader == null)
        {
            classLoader = getClass().getClassLoader();
        }

        try
        {
            fileItemClass = classLoader.loadClass(fileItemClassName);
        }
        catch (Exception e)
        {
            throw new FileUploadException(e.toString());
        }

        if (fileItemClass == null)
        {
            throw new FileUploadException(
                    "Failed to load FileItem class: " + fileItemClassName);
        }

        // Find the newInstance() method.
        Class[] parameterTypes = new Class[] {
                String.class, String.class, String.class,
                Integer.TYPE, Integer.TYPE };
        Method newInstanceMethod = MethodUtils.getAccessibleMethod(
                fileItemClass, "newInstance", parameterTypes);

        if (newInstanceMethod == null)
        {
            throw new FileUploadException(
                    "Failed find newInstance() method in FileItem class: "
                            + fileItemClassName);
        }

        // Cache the method so that all this only happens once.
        this.newInstanceMethod = newInstanceMethod;
        return newInstanceMethod;
    }


    /**
     * <p> Parses the <code>header-part</code> and returns as key/value
     * pairs.
     *
     * <p> If there are multiple headers of the same names, the name
     * will map to a comma-separated list containing the values.
     *
     * @param headerPart The <code>header-part</code> of the current
     *                   <code>encapsulation</code>.
     *
     * @return A <code>Map</code> containing the parsed HTTP request headers.
     */
    protected Map /* String, String */ parseHeaders(String headerPart)
    {
        Map headers = new HashMap();
        char buffer[] = new char[MAX_HEADER_SIZE];
        boolean done = false;
        int j = 0;
        int i;
        String header, headerName, headerValue;
        try
        {
            while (!done)
            {
                i = 0;
                // Copy a single line of characters into the buffer,
                // omitting trailing CRLF.
                while (i < 2 || buffer[i - 2] != '\r' || buffer[i - 1] != '\n')
                {
                    buffer[i++] = headerPart.charAt(j++);
                }
                header = new String(buffer, 0, i - 2);
                if (header.equals(""))
                {
                    done = true;
                }
                else
                {
                    if (header.indexOf(':') == -1)
                    {
                        // This header line is malformed, skip it.
                        continue;
                    }
                    headerName = header.substring(0, header.indexOf(':'))
                        .trim().toLowerCase();
                    headerValue =
                        header.substring(header.indexOf(':') + 1).trim();
                    if (getHeader(headers, headerName) != null)
                    {
                        // More that one heder of that name exists,
                        // append to the list.
                        headers.put(headerName,
                                    getHeader(headers, headerName) + ',' +
                                    headerValue);
                    }
                    else
                    {
                        headers.put(headerName, headerValue);
                    }
                }
            }
        }
        catch (IndexOutOfBoundsException e)
        {
            // Headers were malformed. continue with all that was
            // parsed.
        }
        return headers;
    }


    /**
     * Returns the header with the specified name from the supplied map. The
     * header lookup is case-insensitive.
     *
     * @param headers A <code>Map</code> containing the HTTP request headers.
     * @param name    The name of the header to return.
     *
     * @return The value of specified header, or a comma-separated list if
     *         there were multiple headers of that name.
     */
    protected final String getHeader(Map /* String, String */ headers,
                                     String name)
    {
        return (String) headers.get(name.toLowerCase());
    }

}