/**
 * <p>Convert a <code>String</code> to an <code>int</code>, returning
 * <code>zero</code> if the conversion fails.</p>
 *
 * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
 *
 * <pre>
 *   NumberUtil.toInt(null) = 0
 *   NumberUtil.toInt("")   = 0
 *   NumberUtil.toInt("1")  = 1
 * </pre>
 *
 * @param str the string to convert, may be null
 * @return the int represented by the string, or <code>zero</code> if
 * conversion fails
 */
NumberUtil.toInt(String str);

/**
 * <p>Convert a <code>String</code> to an <code>int</code>, returning a
 * default value if the conversion fails.</p>
 *
 * <p>If the string is <code>null</code>, the default value is returned.</p>
 *
 * <pre>
 *   NumberUtil.toInt(null, 1) = 1
 *   NumberUtil.toInt("", 1)   = 1
 *   NumberUtil.toInt("1", 0)  = 1
 * </pre>
 *
 * @param str          the string to convert, may be null
 * @param defaultValue the default value
 * @return the int represented by the string, or the default if conversion fails
 */
NumberUtil.toInt(String str, int defaultValue);

/**
 * <p>Convert a <code>String</code> to a <code>long</code>, returning
 * <code>zero</code> if the conversion fails.</p>
 *
 * <p>If the string is <code>null</code>, <code>zero</code> is returned.</p>
 *
 * <pre>
 *   NumberUtil.toLong(null) = 0L
 *   NumberUtil.toLong("")   = 0L
 *   NumberUtil.toLong("1")  = 1L
 * </pre>
 *
 * @param str the string to convert, may be null
 * @return the long represented by the string, or <code>0</code> if
 * conversion fails
 */
NumberUtil.toLong(String str);

/**
 * <p>Convert a <code>String</code> to a <code>long</code>, returning a
 * default value if the conversion fails.</p>
 *
 * <p>If the string is <code>null</code>, the default value is returned.</p>
 *
 * <pre>
 *   NumberUtil.toLong(null, 1L) = 1L
 *   NumberUtil.toLong("", 1L)   = 1L
 *   NumberUtil.toLong("1", 0L)  = 1L
 * </pre>
 *
 * @param str          the string to convert, may be null
 * @param defaultValue the default value
 * @return the long represented by the string, or the default if conversion fails
 */
NumberUtil.toLong(String str, long defaultValue);

/**
 * 将 long 转短字符串 为 62 进制
 * @param i 数字
 * @return 短字符串
 */
NumberUtil.to62Str(long i);