StringUtils工具类split方法对比

/**
 * <p>Splits the provided text into an array, separators specified.
 * This is an alternative to using StringTokenizer.</p>
 *
 * <p>The separator is not included in the returned String array.
 * Adjacent separators are treated as one separator.
 * For more control over the split use the StrTokenizer class.</p>
 *
 * <p>A {@code null} input String returns {@code null}.
 * A {@code null} separatorChars splits on whitespace.</p>
 *
 * <pre>
 * StringUtils.split(null, *)         = null
 * StringUtils.split("", *)           = []
 * StringUtils.split("abc def", null) = ["abc", "def"]
 * StringUtils.split("abc def", " ")  = ["abc", "def"]
 * StringUtils.split("abc  def", " ") = ["abc", "def"]
 * StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
 * </pre>
 *
 * @param str  the String to parse, may be null
 * @param separatorChars  the characters used as the delimiters,
 *  {@code null} splits on whitespace
 * @return an array of parsed Strings, {@code null} if null String input
 */
public static String[] split(final String str, final String separatorChars) {
    return splitWorker(str, separatorChars, -1, false);
}

/**
 * Split a {@code String} at the first occurrence of the delimiter.
 * Does not include the delimiter in the result.
 * @param toSplit the string to split (potentially {@code null} or empty)
 * @param delimiter to split the string up with (potentially {@code null} or empty)
 * @return a two element array with index 0 being before the delimiter, and
 * index 1 being after the delimiter (neither element includes the delimiter);
 * or {@code null} if the delimiter wasn't found in the given input {@code String}
 */
@Nullable
public static String[] split(@Nullable String toSplit, @Nullable String delimiter) {
   if (!hasLength(toSplit) || !hasLength(delimiter)) {
      return null;
   }
   int offset = toSplit.indexOf(delimiter);
   if (offset < 0) {
      return null;
   }

   String beforeDelimiter = toSplit.substring(0, offset);
   String afterDelimiter = toSplit.substring(offset + delimiter.length());
   return new String[] {beforeDelimiter, afterDelimiter};
}
/**
 * Check that the given {@code String} is neither {@code null} nor of length 0.
 * <p>Note: this method returns {@code true} for a {@code String} that
 * purely consists of whitespace.
 * @param str the {@code String} to check (may be {@code null})
 * @return {@code true} if the {@code String} is not {@code null} and has length
 * @see #hasLength(CharSequence)
 * @see #hasText(String)
 */
public static boolean hasLength(@Nullable String str) {
   return (str != null && !str.isEmpty());
}