fileuploadbase.java

解觖java技术中后台无法上传数给的情况

                                OutputStream os = item.getOutputStream();
                                try {
                                    multi.readBodyData(os);
                                } finally {
                                    os.close();
                                }
                                items.add(item);
                            } else {
                                // Ignore anything but files inside
                                // multipart/mixed.
                                multi.discardBodyData();
                            }
                            nextSubPart = multi.readBoundary();
                        }
                        multi.setBoundary(boundary);
                    } else {
                        FileItem item = createItem(headers,
                                getFileName(headers) == null);
                        OutputStream os = item.getOutputStream();
                        try {
                            multi.readBodyData(os);
                        } finally {
                            os.close();
                        }
                        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 boundary from the <code>Content-type</code> header.
     *
     * @param contentType The value of the content type header from which to
     *                    extract the boundary value.
     *
     * @return The boundary, as a byte array.
     */
    protected byte[] getBoundary(String contentType) {
        ParameterParser parser = new ParameterParser();
        parser.setLowerCaseNames(true);
        // Parameter parser can handle null input
        Map params = parser.parse(contentType, ';');
        String boundaryStr = (String) params.get("boundary");

        if (boundaryStr == null) {
            return null;
        }
        byte[] boundary;
        try {
            boundary = boundaryStr.getBytes("ISO-8859-1");
        } catch (UnsupportedEncodingException e) {
            boundary = boundaryStr.getBytes();
        }
        return boundary;
    }


    /**
     * 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 != null) {
            String cd_lower = cd.toLowerCase(); // minhnn: fix lower filename (thread=3485) (Thanks Serobit)
            if (cd_lower.startsWith(FORM_DATA) || cd_lower.startsWith(ATTACHMENT)) {
                ParameterParser parser = new ParameterParser();
                parser.setLowerCaseNames(true);
                // Parameter parser can handle null input
                Map params = parser.parse(cd, ';');
                if (params.containsKey("filename")) {
                    fileName = (String) params.get("filename");
                    if (fileName != null) {
                        fileName = fileName.trim();
                    } else {
                        // Even if there is no value, the parameter is present,
                        // so we return an empty file name rather than no file
                        // name.
                        fileName = "";
                    }
                }
            }
        }
        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.toLowerCase().startsWith(FORM_DATA)) {

            ParameterParser parser = new ParameterParser();
            parser.setLowerCaseNames(true);
            // Parameter parser can handle null input
            Map params = parser.parse(cd, ';');
            fieldName = (String) params.get("name");
            if (fieldName != null) {
                fieldName = fieldName.trim();
            }
        }
        return fieldName;
    }


    /**
     * Creates a new {@link FileItem} instance.
     *
     * @param headers       A <code>Map</code> containing the HTTP request
     *                      headers.
     * @param isFormField   Whether or not this item is a form field, as
     *                      opposed to a file.
     *
     * @return A newly created <code>FileItem</code> instance.
     *
     * @throws FileUploadException if an error occurs.
     */
    protected FileItem createItem(Map /* String, String */ headers,
                                  boolean isFormField)
        throws FileUploadException {
        return getFileItemFactory().createItem(getFieldName(headers),
                getHeader(headers, CONTENT_TYPE),
                isFormField,
                getFileName(headers));
    }


    /**
     * <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());
    }


    /**
     * Thrown to indicate that the request is not a multipart request.
     */
    public static class InvalidContentTypeException
        extends FileUploadException {
        /**
         * Constructs a <code>InvalidContentTypeException</code> with no
         * detail message.
         */
        public InvalidContentTypeException() {
            super();
        }

        /**
         * Constructs an <code>InvalidContentTypeException</code> with
         * the specified detail message.
         *
         * @param message The detail message.
         */
        public InvalidContentTypeException(String message) {
            super(message);
        }
    }


    /**
     * Thrown to indicate that the request size is not specified.
     */
    public static class UnknownSizeException
        extends FileUploadException {
        /**
         * Constructs a <code>UnknownSizeException</code> with no
         * detail message.
         */
        public UnknownSizeException() {
            super();
        }

        /**
         * Constructs an <code>UnknownSizeException</code> with
         * the specified detail message.
         *
         * @param message The detail message.
         */
        public UnknownSizeException(String message) {
            super(message);
        }
    }


    /**
     * Thrown to indicate that the request size exceeds the configured maximum.
     */
    public static class SizeLimitExceededException
        extends FileUploadException {
        /**
         * The actual size of the request.
         */
        private long actual;

        /**
         * The maximum permitted size of the request.
         */
        private long permitted;

        /**
         * Constructs a <code>SizeExceededException</code> with no
         * detail message.
         */
        public SizeLimitExceededException() {
            super();
        }

        /**
         * Constructs a <code>SizeExceededException</code> with
         * the specified detail message.
         *
         * @param message The detail message.
         */
        public SizeLimitExceededException(String message) {
            super(message);
        }

        /**
         * Constructs a <code>SizeExceededException</code> with
         * the specified detail message, and actual and permitted sizes.
         *
         * @param message   The detail message.
         * @param actual    The actual request size.
         * @param permitted The maximum permitted request size.
         */
        public SizeLimitExceededException(String message, long actual,
                long permitted) {
            super(message);
            this.actual = actual;
            this.permitted = permitted;
        }

        /**
         * Retrieves the actual size of the request.
         *
         * @return The actual size of the request.
         */
        public long getActualSize() {
            return actual;
        }

        /**
         * Retrieves the permitted size of the request.
         *
         * @return The permitted size of the request.
         */
        public long getPermittedSize() {
            return permitted;
        }
    }

}