Java 日期时间处理详解(API、格式化)

import java.util.Date;
import java.util.Calendar;
public class DateTimeExample {
    public static void main(String[] args) {
        Date now = new Date();
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(now);
        System.out.println("当前日期：" + now);
        System.out.println("当前年份：" + calendar.get(Calendar.YEAR));
        System.out.println("当前月份：" + (calendar.get(Calendar.MONTH) + 1));
        System.out.println("当前日期：" + calendar.get(Calendar.DAY_OF_MONTH));
        System.out.println("当前小时：" + calendar.get(Calendar.HOUR_OF_DAY));
        System.out.println("当前分钟：" + calendar.get(Calendar.MINUTE));
        System.out.println("当前秒：" + calendar.get(Calendar.SECOND));
    }
}

import java.time.LocalDate;
import java.time.LocalTime;
import java.time.LocalDateTime;
public class DateTimeExample {
    public static void main(String[] args) {
        LocalDate date = LocalDate.now();
        LocalTime time = LocalTime.now();
        LocalDateTime dateTime = LocalDateTime.now();
        System.out.println("当前日期：" + date);
        System.out.println("当前时间：" + time);
        System.out.println("当前日期和时间：" + dateTime);
    }
}

import java.text.SimpleDateFormat;
import java.util.Date;
public class DateTimeExample {
    public static void main(String[] args) {
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date now = new Date();
        String formattedDate = dateFormat.format(now);
        System.out.println("格式化后的日期：" + formattedDate);
    }
}