java关于String.split("|")的使用方式

public class TestSplit {
    public static void main(String[] a){
        String test = "中文|英文";
        print(test.split("|"));
        print(test.split(""));
        print(test.split("\\|"));
    }
    public static void print(String[] a){
        System.out.println("============================");
        for(String i:a){
            System.out.println(i);
        }
        System.out.println("============================\n");
    }
}

/**
 * Splits this string around matches of the given <a
 * href="../util/regex/Pattern.html#sum" rel="external nofollow" >regular expression</a>.
 *
 * <p> This method works as if by invoking the two-argument {@link
 * #split(String, int) split} method with the given expression and a limit
 * argument of zero.  Trailing empty strings are therefore not included in
 * the resulting array.
 *
 * <p> The string {@code "boo:and:foo"}, for example, yields the following
 * results with these expressions:
 *
 * <blockquote><table cellpadding=1 cellspacing=0 summary="Split examples showing regex and result">
 * <tr>
 *  <th>Regex</th>
 *  <th>Result</th>
 * </tr>
 * <tr><td align=center>:</td>
 *     <td>{@code { "boo", "and", "foo" }}</td></tr>
 * <tr><td align=center>o</td>
 *     <td>{@code { "b", "", ":and:f" }}</td></tr>
 * </table></blockquote>
 *
 *
 * @param  regex
 *         the delimiting regular expression
 *
 * @return  the array of strings computed by splitting this string
 *          around matches of the given regular expression
 *
 * @throws  PatternSyntaxException
 *          if the regular expression's syntax is invalid
 *
 * @see java.util.regex.Pattern
 *
 * @since 1.4
 * @spec JSR-51
 */
public String[] split(String regex) { ... }

String[] s1 = "a.b.c".split("\\.");
System.out.println(Arrays.asList(s1)); //[a, b, c]
String[] s2 = "a.b.c".split("[.]");
System.out.println(Arrays.asList(s2)); //[a, b, c]