Java：匹配###-9999的正则表达式

Question

###-9999

[A-Z]{3})(-)(\\d{4}

Answer 1

请注意，正则表达式的计算成本可能很高，因为每次运行都必须对其进行编译。因此，使用预先编译的模式有助于降低这种成本。

下面是来自该来源的基准的一个示例：

Time for String: 67.693 ms
Time for Pattern: 12.178 ms

以下是您的学生ID场景的可运行方法：

import java.util.List;
import java.util.regex.Pattern;

class Patterns {

    public static final String STUDENT_ID_REGEX = "[A-Z]{3}-[0-9]{4}";

    private static final Pattern STUDENT_ID_PATTERN = Pattern.compile(STUDENT_ID_REGEX);

    public static boolean isStudentId(String candidate) {
        return STUDENT_ID_PATTERN.matcher(candidate).matches();
    }
}

public class RegexTest {

    public static void main(String[] args) {

        List<String> studentIds = List.of("ABC-1234", "ABC_1234", "AB-1234", "ABC-123", "abc-1234", "aBc-1234", "ABCD-A123", "SomeString", "123-ABCD");

        studentIds.forEach(id -> {
            System.out.println(id + " matches " + Patterns.STUDENT_ID_REGEX + "? " + Patterns.isStudentId(id));
        });
    }
}

ABC-1234 matches [A-Z]{3}-[0-9]{4}? true
ABC_1234 matches [A-Z]{3}-[0-9]{4}? false
AB-1234 matches [A-Z]{3}-[0-9]{4}? false
ABC-123 matches [A-Z]{3}-[0-9]{4}? false
abc-1234 matches [A-Z]{3}-[0-9]{4}? false
aBc-1234 matches [A-Z]{3}-[0-9]{4}? false
ABCD-A123 matches [A-Z]{3}-[0-9]{4}? false
SomeString matches [A-Z]{3}-[0-9]{4}? false
123-ABCD matches [A-Z]{3}-[0-9]{4}? false

AdoptOpenJDK jdk-16.0.1.9-hotspot