// 創(chuàng)建SimpleDateFormat對(duì)象，指定日期時(shí)間格式
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

// 待驗(yàn)證的日期時(shí)間字符串
String dateTimeString = "2021-06-30 12:34:56";

try {
    // 將日期時(shí)間字符串轉(zhuǎn)化為Date對(duì)象
    Date dateTime = dateFormat.parse(dateTimeString);

    // 驗(yàn)證日期時(shí)間字符串的格式和有效性成功
    System.out.println("日期時(shí)間字符串格式和有效性驗(yàn)證通過");
} catch (ParseException e) {
    // 驗(yàn)證日期時(shí)間字符串的格式和有效性失敗
    System.err.println("日期時(shí)間字符串格式和有效性驗(yàn)證失敗：" + e.getMessage());
}

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;

public class DateTimeFormatValidator {
    public static void main(String[] args) {
        String userInput = "2021-08-31 10:30:00";
        String pattern = "yyyy-MM-dd HH:mm:ss";
        try {
            // 創(chuàng)建日期時(shí)間格式化對(duì)象
            DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
            // 將用戶輸入的字符串解析為L(zhǎng)ocalDateTime對(duì)象
            LocalDateTime dateTime = LocalDateTime.parse(userInput, formatter);
            // 打印解析后的日期時(shí)間
            System.out.println(dateTime);
        } catch (DateTimeParseException e) {
            // 解析失敗，說明輸入的字符串不符合指定的日期時(shí)間格式
            System.out.println("Invalid date/time format: " + userInput);
        }
    }
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class DateTimeValidator {
    private static final String DATE_PATTERN = "yyyy-MM-dd";
    private static final String TIME_PATTERN = "HH:mm:ss";
    public static boolean isValidDate(String date) {
        return isValidFormat(DATE_PATTERN, date);
    }
    public static boolean isValidTime(String time) {
        return isValidFormat(TIME_PATTERN, time);
    }
    private static boolean isValidFormat(String pattern, String value) {
        boolean isValid = false;
        Pattern regexPattern = Pattern.compile(pattern);
        Matcher matcher = regexPattern.matcher(value);
        if (matcher.matches()) {
            isValid = true;
        }
        return isValid;
    }
}

boolean isDateValid = DateTimeValidator.isValidDate("2021-12-31"); // true
boolean isTimeValid = DateTimeValidator.isValidTime("23:59:59"); // true