如何使用 Java RegEx 匹配一组固定字符


字符类允许你从一个固定的字符集中接受单个字符。例如,

  • 表达式“[tmp]”匹配字符 t 或 m 或 p。

  • 表达式“[^tp]”匹配除 t 或 p 之外的字符。

例 1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
   public static void main(String args[]) {
      //Reading String from user
      System.out.println("Enter a String");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      //Regular expression to match the characters t or, m or, p
      String regex = "[tmp]";
      //Compiling the regular expression
      Pattern pattern = Pattern.compile(regex);
      //Retrieving the matcher object
      Matcher matcher = pattern.matcher(input);
      int count = 0;
      while(matcher.find()) {
         count++;
      }
      System.out.println("Occurrences: "+count);
   }
}

输出

Enter a String
hello how are you welcome to tutorialspoint
Occurrences :6

例 2

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
   public static void main(String args[]) {
      //Reading String from user
      System.out.println("Enter a String");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      String regex = "[^abcdef]";
      //Compiling the regular expression
      Pattern pattern = Pattern.compile(regex);
      //Retrieving the matcher object
      Matcher matcher = pattern.matcher(input);
      int count = 0;
      while(matcher.find()) {
         count++;
      }
      System.out.println("Occurrences :"+count);
   }
}

输出

Enter a String
Hello how are you welcome to tutorialspoint
Occurrences :36

更新于:2019-11-19

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