Posix字符类\ p {Alnum} Java regex
此类与字母数字字符匹配。
例
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class AlphanumericExample {
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{Alnum}]";
//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 alphanumeric characters: "+count);
}
}输出1
Enter a string sample 123 Number of digits: 9
输出2
Enter a string @$#%&&#* Number of alphanumeric characters: 0
例
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
public static void main( String args[] ) {
//正则表达式 to match lower case letters
String regex = "^\\p{Alnum}+$";
//获取输入数据
Scanner sc = new Scanner(System.in);
System.out.println("Enter 5 input strings: ");
String input[] = new String[5];
for (int i=0; i<5; i++) {
input[i] = sc.nextLine();
}
//创建一个Pattern对象
Pattern p = Pattern.compile(regex);
System.out.println("Strings with only alphanumeric characters: ");
for(int i=0; i<5;i++) {
//创建一个Matcher对象
Matcher m = p.matcher(input[i]);
if(m.matches()) {
System.out.println(m.group());
}
}
}
}输出结果
Enter 5 input strings: hello 1234 243test ##$$@ *** Strings with only alphanumeric characters: hello 1234 243test