1, the predefined character classes
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Any character
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\ D figures: [0-9]
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\ D non-numeric: [^ 0-9]
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\ S whitespace: [\ t \ n \ x0B \ f \ r]
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\ S non-whitespace characters: [^ \ s]
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\ W word character: [a-zA-Z_0-9]
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\ W non-word characters: [^ \ w]
2, the code
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. Results
