Java8时间api之LocalDate/LocalDateTime的用法详解

 Date date = new Date(2022,1,1);
 System.out.println(date);

Calendar calendar = Calendar.getInstance();
calendar.set(2022, Calendar.AUGUST, 2);

 calendar.add(Calendar.DAY_OF_MONTH, 1);

LocalDate now = LocalDate.now(); //获取当前的年月日  2023-05-07
System.out.println(now);
LocalTime now1 = LocalTime.now();//获取当前时间   13:05:46.609
System.out.println(now1);
LocalDateTime now2 = LocalDateTime.now();   //获取当前日期加时间  2023-05-07T13:05:46.609
System.out.println(now2);

LocalDate now = LocalDate.now(); //获取当前的年月日  2023-05-07
System.out.println(now);
LocalTime now1 = LocalTime.now();//获取当前时间   13:05:46.609
System.out.println(now1);
LocalDateTime now2 = LocalDateTime.now();   //获取当前日期加时间  2023-05-07T13:05:46.609
System.out.println(now2);

LocalDateTime now = LocalDateTime.now();
int year = now.getYear();
int dayOfYear = now.getDayOfYear();
int hour = now.getHour();
int minute = now.getMinute();
int second = now.getSecond();

LocalDate now = LocalDate.now();
//JDK1.8 格式化日期的类 DateTimeFormatter
//指定格式
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy年MM月dd日");
String dateStr = now.format(formatter);
System.out.println(dateStr); // 2023年05月07日
LocalDateTime localDateTime = LocalDateTime.now();
DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern("yyyy年MM月dd日 HH点mm分ss秒");
//把日期对象，格式化成日期字符串
String str = localDateTime.format(formatter2);
System.out.println(str); //2023年05月07日 13点57分53秒

System.out.println(localDateTime.toLocalDate()); //2023-05-07
System.out.println(localDateTime.toLocalTime());// 13:57:53.061

    // isAfter() 判断一个日期是否在指定日期之后
    // isBefore() 判断一个日期是否在指定日期之前
    // isEqual();
    // 判断两个日期是否相同
    // isLeapYear() 判断是否是闰年注意是LocalDate类中的方法
    LocalDateTime now = LocalDateTime.now();
    LocalDateTime of = LocalDateTime.of(2023, 5, 7,14,0,0);
    System.out.println("当前时间为"+now); //当前时间为2023-05-07T14:04:18.676
    boolean after = now.isAfter(of);
    System.out.println(after);  // true
    boolean before = of.isBefore(now);
    System.out.println(before); //true
    boolean equal = now.isEqual(of);
    System.out.println(equal); //false
    boolean equal1 = of.isEqual(of);
    System.out.println(equal1); //true
    //判断是不是闰年
    boolean leapYear = now.toLocalDate().isLeapYear();
    System.out.println(leapYear); //false

//      now.getMonth().compareTo() 月份之间比较 相同则为0
        Month month = LocalDate.now().getMonth();
        Month month1 = LocalDate.of(2023, 6, 1).getMonth();
        System.out.println(month.compareTo(month1));

String dateStr = "2022-12-03";
LocalDate parse = LocalDate.parse(dateStr);
System.out.println(parse);
String dateStr2 = "2022年12月03日";
//按照指定格式来解析
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy年MM月dd日");
LocalDate parse2 = LocalDate.parse(dateStr2, formatter); //
System.out.println(parse2);
System.out.println("======================");
String dateStr3 = "2021年10月05日 14点20分30秒";
DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern("yyyy年MM月dd日 HH点mm分ss秒");
LocalDateTime parse1 = LocalDateTime.parse(dateStr3, formatter2);
System.out.println(parse1);

LocalDateTime ldt =LocalDateTime.now();
LocalDateTime localDateTime = ldt.plusYears(1);
LocalDateTime localDateTime1 = ldt.plusMonths(3);
LocalDateTime localDateTime2=ldt.plusHours(10);
LocalDateTime localDateTime2 = ldt.minusYears(8);

    //Duration:用于计算两个"时间”间隔的类
    Duration betweenNowAnd = Duration.between(preious, end);
    //long seconds = between.getSeconds(); //间隔的秒值
    long l = betweenNowAnd.toMillis();
    System.out.println("耗时：" + l + "毫秒");
    LocalDate birthday = LocalDate.of(2000, 3, 20);
    LocalDate nowday = LocalDate.now();
    //Period:用于计算两个“日期”间隔的类
    Period between = Period.between(birthday, nowday);
    int years = between.getYears();
    int months = between.getMonths();
    int days = between.getDays();
    System.out.println(years);
    System.out.println(months);
    System.out.println(days);

//创建日期对象
LocalDateTime now = LocalDateTime.now();
//获取不同国家的日期时间根据各个地区的时区ID名创建对象
ZoneId timeID = ZoneId.of("Asia/Shanghai");
//根据时区ID获取带有时区的日期时间对象
ZonedDateTime time = now.atZone(timeID);
System.out.println(time);
//方式2 通过时区ID 获取日期对象
LocalDateTime now2 = LocalDateTime.now(ZoneId.of("Asia/Shanghai"));
System.out.println(now2);