public class Test7 {

    public static void main(String[] args) {

        //两种写法都可以

        String regex = "^[A-Z].*\\.$";//"^[A-Z].*\\."这样也对

        String regex1 = "\\p{Upper}.*\\.$";

        String str = "D.";

        String str1 = "Dfasdfasfasfdasfdasfasfasdf.";

        String str2 = "Dfasdfasfasfdasfdasfasfasdf.E";

        System.out.println(str.matches(regex));

        System.out.println(str1.matches(regex));

        System.out.println(str2.matches(regex));

        System.out.println(str.matches(regex1));

        System.out.println(str1.matches(regex1));

        System.out.println(str2.matches(regex1));

    }

}

true

false

true

true

false

package net.mindview.strings;

import java.util.Arrays;

public class Splitting {

    public static String knights = "Then, when you have found the shrubbery, you must cut down the mightiest tree in the forest... with... a herring!";

    public static void split(String regex){

        System.out.println(Arrays.toString(knights.split(regex)));

    }

    public static void main(String[] args) {

        //表示的时按照空格分割字符串

        //运行结果:[Then,, when, you, have, found, the, shrubbery,, you, must, cut, down, the, mightiest, tree, in, the, forest..., with..., a, herring!]

        split(" ");

        //表示按照非单次字符分割字符串--这里的非单次字符是空格和,

        //运行结果:[Then, when, you, have, found, the, shrubbery, you, must, cut, down, the, mightiest, tree, in, the, forest, with, a, herring]

        split("\\W+");

        //这个表示:费单次字符之前带n的地方进行分割字符串 这里的分割符是n空格和n,

        //运行结果:[The, whe, you have found the shrubbery, you must cut dow, the mightiest tree i, the forest... with... a herring!]

        split("n\\W+");

    }

}

package net.mindview.strings.test8;

import net.mindview.strings.Splitting;

public class Test8 {

    public static void main(String[] args) {

        String regex = "the|you";

        Splitting.split(regex);

    }

}

package net.mindview.strings.test9;

import net.mindview.strings.Splitting;

public class Test9 {

    public static void main(String[] args) {

        String regex = "A|E|I|O|U|a|e|i|o|u";

        //通过嵌入式标志表达式  (?i) 也可以启用不区分大小写的匹配。

        String regex1 = "(?i)a|e|i|o|u";

        //[abc] 表示a或b或c

        String regex2 = "(?i)[aeiou]";

        System.out.println(Splitting.knights.replaceAll(regex, "_"));

        System.out.println(Splitting.knights.replaceAll(regex1, "_"));

        System.out.println(Splitting.knights.replaceAll(regex2, "_"));

    }

}