如何用 Java 檢查輸入中的多個正則表示式?
“|” 元字元:Java 正則表示式中的元字元 “|” 允許你匹配多個正則表示式,比如,如果你需要用多個表示式匹配某段輸入文字,你需要用它將它們分隔開,比如
exp1|exp2|exp3
示例
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class SampleExample { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter your input: "); String input = sc.nextLine(); //Regular expression String regex = "\d{10}|^[aeiou]"; //Creating a pattern object Pattern pattern = Pattern.compile(regex); //Creating a Matcher object Matcher matcher = pattern.matcher(input); if(matcher.find()) { System.out.println(input+" is valid"); }else { System.out.println(input+" is not valid"); } } }
輸出 1
Enter your input: 9848033228 9848033228 is valid
輸出 2
Enter your input: an apple a day keeps doctor away an apple a day keeps doctor away is valid
使用列表物件
另一個解決方案是使用單個模式物件編譯所有正則表示式,並將它們新增到一個列表物件中,然後在輸入文字中查詢匹配項,如下所示:
List list = new ArrayList<>(); list.add(Pattern.compile(regex1)); list.add(Pattern.compile(regex2)); for (Pattern pattern: list) { Matcher matcher = pattern.matcher(input); if(matcher.find()) { . . . . . . . . . . . . . . . }else { . . . . . . . . . . . . . . . } }
示例
import java.util.ArrayList; import java.util.List; import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class MultipleRegex { public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.println("Enter your input: "); String input = sc.nextLine(); //Regular expressions String regex1 = "\d{10}"; String regex2 = "^[aeiou]"; //Creating a pattern objects Pattern pattern1 = Pattern.compile(regex1); Pattern pattern2 = Pattern.compile(regex2); //Creating an List object List<Pattern> patterns = new ArrayList<>(); patterns.add(pattern1); patterns.add(pattern2); for (Pattern pattern: patterns) { Matcher matcher = pattern.matcher(input); if(matcher.find()) { System.out.println("For regex "+pattern.pattern()+" "+input+" is valid"); } else { System.out.println("For regex "+pattern.pattern()+" "+input+" is not valid"); } } } }
輸出 1
Enter your input: 9848033228 For regex \d{10} 9848033228 is valid For regex ^[aeiou] 9848033228 is not valid
輸出 2
Enter your input: an apple a day keeps doctor away For regex \d{10} an apple a day keeps doctor away is not valid For regex ^[aeiou] an apple a day keeps doctor away is valid
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