Posix字符类\ p {ASCII} Java regex。
此类与ASCII字符匹配，即\x00-\x7F。
示例
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
public static void main(String args[]) {
//从用户读取字符串
System.out.println("Enter a string");
Scanner sc = new Scanner(System.in);
String input = sc.nextLine();
//正则表达式
String regex = "^[\\p{ASCII}]";
//Compiling the 正则表达式
Pattern pattern = Pattern.compile(regex);
//检索匹配器对象
Matcher matcher = pattern.matcher(input);
int count = 0;
while(matcher.find()) {
count++;
}
System.out.println("Number of non-ASCII characters in the given string: "+count);
}
}输出结果
Enter a string why do we fall Number of non-ASCII characters in the given string: 1