import com.sun.xml.internal.messaging.saaj.packaging.mime.util.ASCIIUtility; //导入依赖的package包/类
/**
 * Parse the InputStream from our DataSource, constructing the
 * appropriate MimeBodyParts.  The <code>parsed</code> flag is
 * set to true, and if true on entry nothing is done.  This
 * method is called by all other methods that need data for
 * the body parts, to make sure the data has been parsed.
 *
 * @since JavaMail 1.2
 */
@Override
protected void parse() throws MessagingException {
    if (parsed)
        return;

    initStream();

    SharedInputStream sin = null;
    if (in instanceof SharedInputStream) {
        sin = (SharedInputStream) in;
    }

    String bnd = "--" + boundary;
    byte[] bndbytes = ASCIIUtility.getBytes(bnd);
    try {
        parse(in, bndbytes, sin);
    } catch (IOException ioex) {
        throw new MessagingException("IO Error", ioex);
    } catch (Exception ex) {
        throw new MessagingException("Error", ex);
    }

    parsed = true;
}