Date和LocalDateTime的相互转换,字符串转LocalDateTime,求日期最晚时间、最早时间、获取整点时间

快来打我* 2022-11-25 11:49 192阅读 0赞

## 导包如下 ##

import java.time.*;
    import java.time.format.DateTimeFormatter;

## 以下是转化代码 ##

# 一、Date转LocalDateTime #

public static LocalDateTime toLocalDateTime(Date date) { 
            // 方法一
            LocalDateTime localDateTime = date.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime();
            // 方法二
            return LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());
        }

# 二、LocalDateTime转Date #

public static Date toDate(LocalDateTime localDateTime) { 
            return Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());
        }

# 三、时间字符串转LocalDateTime #

/** * date string to LocalDateTime * @param dateStr eg: "2020-08-22 10:30:50" * @param pattern eg: "yyyy-MM-dd HH:mm:ss" * @return LocalDateTime */
        public static LocalDateTime toLocalDateTime(String dateStr, String pattern) { 
            return LocalDateTime.parse(dateStr, DateTimeFormatter.ofPattern(pattern));
        }

# 四、Date转OffsetDateTime #

public static OffsetDateTime toOffsetDateTime(Date date) { 
            // 方法一
            OffsetDateTime offsetDateTime = date.toInstant().atZone(ZoneId.systemDefault()).toOffsetDateTime();
            // 方法二
            return ZonedDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()).toOffsetDateTime();
        }
        
        // 测试
        public static void test(){ 
            OffsetDateTime offsetDateTime = toOffsetDateTime(new Date());
            // 当前最后时间 23:59:59
            OffsetDateTime with = offsetDateTime.with(LocalTime.MAX);
            // 当前开始时间 00:00:00
            OffsetDateTime  endDateTime = offsetDateTime.with(LocalTime.MIN);
        }

# 五、OffsetDateTime转Date #

public static Date toDate(OffsetDateTime offsetDateTime){ 
            return Date.from(offsetDateTime.atZoneSameInstant(ZoneId.systemDefault()).toInstant());
        }

# 六、OffsetDateTime转LocalDateTime #

public static LocalDateTime toLocalDateTime(OffsetDateTime offsetDateTime) { 
            return LocalDateTime.ofInstant(offsetDateTime.atZoneSameInstant(ZoneId.systemDefault()).toInstant(), ZoneId.systemDefault());
        }

# 七、获取整点时间 #

/** * 获取整点时间 示例：2020-10-28 10:18:32 返回 2020-10-28 10:00:00 * @param date the date * @return the hour date time */
        public static Date getHour(Date date) { 
            LocalDateTime dateTime = LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());
            return Date.from(LocalDateTime.of(dateTime.toLocalDate(), LocalTime.of(dateTime.getHour(), 0, 0)).atZone(ZoneId.systemDefault()).toInstant());
        }

# 八、LocalDateTime 转 时间戳（秒级） #

@Test
        public void localTimeTest1(){ 
            // 获得当前时间
            LocalDateTime localDateTime = LocalDateTime.now();
            // 将当前时间转为时间戳
            long second = localDateTime.toEpochSecond(ZoneOffset.ofHours(8));
            System.out.println(second);
    
        }

@Test
        public void localTimeTest2(){ 
            // 获得当前时间
            LocalDateTime localDateTime = LocalDateTime.now();
            // 将当前时间转为时间戳
            long second = localDateTime.toInstant(ZoneOffset.ofHours(8)).getEpochSecond();
            System.out.println(second);
    
        }

public void localTimeTest3() { 
            // 获得当前时间
            LocalDateTime localDateTime = LocalDateTime.now();
            // 将当前时间转为时间戳
            long milliseconds = localDateTime.toInstant(ZoneOffset.ofHours(8)).toEpochMilli();
            System.out.println(milliseconds / 1000);
        }

# 九、时间戳 转LocalDateTime #

public void localTimeTest4() { 
            //获得时间戳
            long second = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).getEpochSecond();
            // 将时间戳转为当前时间
            LocalDateTime localDateTime = LocalDateTime.ofEpochSecond(second, 0, ZoneOffset.ofHours(8));
            System.out.println(localDateTime);
        }

public void localTimeTest5() { 
            //获得时间戳
            long milliseconds = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).toEpochMilli();
            // 将时间戳转为当前时间
            LocalDateTime localDateTime = LocalDateTime.ofEpochSecond(milliseconds / 1000, 0, ZoneOffset.ofHours(8));
            System.out.println(localDateTime);
        }

public void localTimeTest6(){ 
            //获得时间戳
            long milliseconds = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).toEpochMilli();
            // 将时间戳转为当前时间
            LocalDateTime localDateTime = Instant.ofEpochMilli(milliseconds).atZone(ZoneOffset.ofHours(8)).toLocalDateTime();
            System.out.println(localDateTime);
        }

# 十、时间戳与LocalDate互转 #

## 时间戳转LocalDate ##

public void localDateTest1(){ 
            //获得时间戳
            long milliseconds = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).toEpochMilli();
            // 将时间戳转为当前时间
            LocalDate localDate = Instant.ofEpochMilli(milliseconds).atZone(ZoneOffset.ofHours(8)).toLocalDate();
            System.out.println(localDate);
        }

public void localDateTest2(){ 
            //获得时间戳
            long seconds = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).getEpochSecond();
            // 将时间戳转为当前时间
            LocalDate localDate = Instant.ofEpochSecond(seconds).atZone(ZoneOffset.ofHours(8)).toLocalDate();
            System.out.println(localDate);
        }

## LocalDate 转 时间戳 ##

public void localDateTest3(){ 
            LocalDate localDate = LocalDate.now();
            //获得时间戳
            long seconds = localDate.atStartOfDay(ZoneOffset.ofHours(8)).toInstant().getEpochSecond();
            System.out.println(seconds);
        }

public void localDateTest4(){ 
            LocalDate localDate = LocalDate.now();
            //获得时间戳
            long seconds = localDate.atStartOfDay(ZoneOffset.ofHours(8)).toInstant().toEpochMilli();
            System.out.println(seconds);
        }

# 备注 #

1、LocalDateTime可以做日期的加减很方便  
2、OffsetDateTime计算00:00:00及23:59:59很方便