JAVA基础(正则表达式--预定义字符类)

1,预定义字符类

  •  . 任何字符        

  •  \d 数字:[0-9]         

  • \D 非数字: [^0-9]       

  •  \s 空白字符:[ \t\n\x0B\f\r]       

  • \S 非空白字符:[^\s]       

  •  \w 单词字符:[a-zA-Z_0-9]             

  • \W 非单词字符:[^\w]

2,代码


public class Demo3_Regex {





    /**

     *     . 任何字符

        \d 数字:[0-9]

        \D 非数字: [^0-9]

        \s 空白字符:[ \t\n\x0B\f\r]

        \S 非空白字符:[^\s]

        \w 单词字符:[a-zA-Z_0-9]

        \W 非单词字符:[^\w]





     */

    public static void main(String[] args) {

        //demo1();

        //demo2();

        //demo3();

        //demo4();

        //demo5();

        //demo6();

        String regex = "\\W";

        System.out.println("a".matches(regex));

        System.out.println("z".matches(regex));

        System.out.println("_".matches(regex));

        System.out.println("%".matches(regex));

    }





    private static void demo6() {

        String regex = "\\w";

        System.out.println("a".matches(regex));

        System.out.println("z".matches(regex));

        System.out.println("_".matches(regex));

        System.out.println("%".matches(regex));

    }





    private static void demo5() {

        String regex = "\\S";

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

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

        System.out.println("a".matches(regex));

    }





    private static void demo4() {

        String regex = "\\s";

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

        System.out.println("    ".matches(regex));                 //一个tab键

        System.out.println("    ".matches(regex));                 //四个空格

    }





    private static void demo3() {

        String regex = "\\D";

        System.out.println("0".matches(regex));

        System.out.println("9".matches(regex));

        System.out.println("a".matches(regex));

    }





    private static void demo2() {

        String regex = "\\d";                    //\代表转义字符,如果想表示\d的话,需要\\d

        System.out.println("0".matches(regex));

        System.out.println("a".matches(regex));

        System.out.println("9".matches(regex));

    }





    private static void demo1() {

        String regex = "..";

        System.out.println("a".matches(regex));

        System.out.println("ab".matches(regex));

    }

}

3,结果

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转载自blog.csdn.net/Cricket_7/article/details/92802993