Example usage for org.apache.poi.util IOUtils peekFirst8Bytes

Introduction

In this page you can find the example usage for org.apache.poi.util IOUtils peekFirst8Bytes.

Prototype

public static byte[] peekFirst8Bytes(InputStream stream) throws IOException, EmptyFileException 

Source Link

Document

Peeks at the first 8 bytes of the stream.

Usage

From source file:com.kplot.web.data.WorkbookFactory.java

License:Apache License

/**
 * Creates the appropriate HSSFWorkbook / XSSFWorkbook from
 *  the given InputStream, which may be password protected.
 * <p>Your input stream MUST either support mark/reset, or
 *  be wrapped as a {@link PushbackInputStream}! Note that
 *  using an {@link InputStream} has a higher memory footprint
 *  than using a {@link File}.</p>
 *
 * <p>Note that in order to properly release resources the
 *  Workbook should be closed after use. Note also that loading
 *  from an InputStream requires more memory than loading
 *  from a File, so prefer {@link #create(File)} where possible.</p>
 *
 *  @param inp The {@link InputStream} to read data from.
 *  @param password The password that should be used or null if no password is necessary.
 *
 *  @return The created Workbook/*from w  w  w  .j  a v  a2 s  .c o m*/
 *
 *  @throws IOException if an error occurs while reading the data
 *  @throws InvalidFormatException if the contents of the file cannot be parsed into a {@link Workbook}
 *  @throws EncryptedDocumentException If the wrong password is given for a protected file
 *  @throws EmptyFileException If an empty stream is given
 */
public static Workbook create(InputStream inp, String password)
        throws IOException, InvalidFormatException, EncryptedDocumentException {
    // If clearly doesn't do mark/reset, wrap up
    if (!inp.markSupported()) {
        inp = new PushbackInputStream(inp, 8);
    }

    // Ensure that there is at least some data there
    byte[] header8 = IOUtils.peekFirst8Bytes(inp);

    // Try to create
    if (NPOIFSFileSystem.hasPOIFSHeader(header8)) {
        NPOIFSFileSystem fs = new NPOIFSFileSystem(inp);
        return create(fs, password);
    }
    if (POIXMLDocument.hasOOXMLHeader(inp)) {
        return new XSSFWorkbook(OPCPackage.open(inp));
    }
    throw new InvalidFormatException("Your InputStream was neither an OLE2 stream, nor an OOXML stream");
}

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From source file:org.talend.dataprep.schema.xls.XlsUtils.java

License:Open Source License

/**
 * Detect the excel format with only peeking at the first 8 bytes of the input stream (leaving the stream untouched).
 *
 * @param inputStream the xls input stream.
 * @return true if the given input stream is a xls new format.
 * @throws IOException if an error occurs.
 *///  w w w  . j  a v  a  2s .c o  m
public static boolean isNewExcelFormat(InputStream inputStream) throws IOException {

    boolean newFormat = false;

    // Ensure that there is at least some data there
    byte[] headers = IOUtils.peekFirst8Bytes(inputStream);

    if (NPOIFSFileSystem.hasPOIFSHeader(headers)) {
        newFormat = false;
    }
    if (POIXMLDocument.hasOOXMLHeader(new ByteArrayInputStream(headers))) {
        newFormat = true;
    }

    return newFormat;

}

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