时间转换整理

快来打我* 2023-06-19 06:53 53阅读 0赞

背景：JDK13、IDEA2019.2.4、Junit5

package com.zsx.test;
    
    import lombok.extern.log4j.Log4j2;
    import org.junit.jupiter.api.Test;
    
    import java.sql.Timestamp;
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.time.*;
    import java.time.format.DateTimeFormatter;
    import java.util.Date;
    
    import static org.junit.jupiter.api.Assertions.assertNotNull;
    import static org.junit.jupiter.api.Assertions.assertThrows;
    
    @Log4j2
    public class DateTimeTest {
    
        @Test
        void getLongTime() {
            long timestamp1 = System.currentTimeMillis();
            // 1575460465012
            log.info("timestamp1 : {}", timestamp1);
    
            // 精确到秒
            long timestamp2 = Instant.now().getEpochSecond();
            // 1575460465
            log.info("timestamp2 : {}", timestamp2);
    
            // 精确到毫秒
            long timestamp3 = Instant.now().toEpochMilli();
            // 1575460465016
            log.info("timestamp3 : {}", timestamp3);
    
        }
    
        @Test
        void testConvertDate() {
            // LocalDate convert Date
            LocalDate localDate = LocalDate.now();
            Date date1 = Date.from(localDate.atStartOfDay(ZoneOffset.systemDefault()).toInstant());
            // 2019-12-04T00:00:00.000+0800
            log.info("date1 : {}", date1);
            assertNotNull(date1);
    
            // LocalDateTime convert Date
            LocalDateTime localDateTime = LocalDateTime.now();
            Date date2 = Date.from(localDateTime.atZone(ZoneOffset.systemDefault()).toInstant());
            // 2019-12-04T18:59:10.282+0800
            log.info("date2 : {}", date2);
            assertNotNull(date2);
    
            // String convert Date
            try {
                String dateStr = "2019-12-04 20:27:35";
                Date date3 = new SimpleDateFormat("yyyy-MM-dd").parse(dateStr);
                // 2019-12-04T00:00:00.000+0800
                log.info("date3 : {}", date3);
            } catch (ParseException e) {
                e.printStackTrace();
            }
    
        }
    
        @Test
        void testConvertLocalDateTime() {
            // Date convert LocalDateTime
            Date date = new Date();
            LocalDateTime localDateTime0 = date.toInstant().atZone(ZoneOffset.systemDefault()).toLocalDateTime();
            // 2019-12-04T20:18:10.027
            log.info("localDateTime10 : {}", localDateTime0);
    
            LocalDateTime localDateTime1 = LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());
            // 2019-12-04T20:18:10.027
            log.info("localDateTime1 : {}", localDateTime1);
    
            // long convert LocalDateTime
            long timestamp = System.currentTimeMillis();
            LocalDateTime localDateTime2 = Instant.ofEpochMilli(timestamp).atZone(ZoneOffset.systemDefault()).toLocalDateTime();
            // 2019-12-04T20:18:10.034
            log.info("localDateTime2 : {}", localDateTime2);
    
            // Timestamp convert LocalDateTime
            Timestamp timestamp1 = new Timestamp(System.currentTimeMillis());
            LocalDateTime localDateTime3 = timestamp1.toLocalDateTime();
            // 2019-12-04T20:18:10.035
            log.info("localDateTime3 : {}", localDateTime3);
    
            LocalDateTime localDateTime4 = LocalDateTime.ofInstant(timestamp1.toInstant(), ZoneId.systemDefault());
            // 2019-12-04T20:18:10.035
            log.info("localDateTime4 : {}", localDateTime4);
    
            // LocalDate convert LocalDateTime
            LocalDate localDate = LocalDate.now();
            LocalDateTime localDateTime5 = localDate.atStartOfDay().atZone(ZoneId.systemDefault()).toLocalDateTime();
            // 2019-12-04T00:00
            log.info("localDateTime5 : {}", localDateTime5);
    
            // String convert LocalDateTime
            String dateStr = "2019-12-04 20:23:25";
            DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            LocalDateTime localDateTime6 = LocalDateTime.parse(dateStr, dtf);
            // 2019-12-04T20:23:25
            log.info("localDateTime6 : {}", localDateTime6);
    
            // Instant convert LocalDateTime
            Instant instant = Instant.now();
            LocalDateTime localDateTime7 = LocalDateTime.ofInstant(instant, ZoneOffset.systemDefault());
            // 2019-12-04T23:10:44.409902100
            log.info("localDateTime7 : {}", localDateTime7);
        }
    
        @Test
        void testConvertLocalDate() {
            // Date convert LocalDate
            Date date = new Date();
            LocalDate localDate0 = date.toInstant().atZone(ZoneOffset.systemDefault()).toLocalDate();
            // 2019-12-04
            log.info("localDate0 : {}", localDate0);
    
            LocalDate localDate1 = LocalDate.ofInstant(date.toInstant(), ZoneId.systemDefault());
            // 2019-12-04
            log.info("localDate1 : {}", localDate1);
    
            // long convert LocalDate
            long timestamp = Instant.now().toEpochMilli();
            LocalDate localDate2 = Instant.ofEpochMilli(timestamp).atZone(ZoneOffset.systemDefault()).toLocalDate();
            // 2019-12-04
            log.info("localDate2 : {}", localDate2);
    
            // LocalDateTime convert LocalDate
            LocalDateTime localDateTime = LocalDateTime.now();
            LocalDate localDate3 = localDateTime.toLocalDate();
            // 2019-12-04
            log.info("localDate3 : {}", localDate3);
    
            DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            String dateStr = "2019-12-04 19:50:09";
            // String convert LocalDate
            LocalDate localDate4 = LocalDate.parse(dateStr, dtf);
            // 2019-12-04
            log.info("localDate4 : {}", localDate4);
        }
    
        @Test
        void testConvertLong() {
            // LocalDate convert long
            LocalDate localDate = LocalDate.now();
            long timestamp1 = localDate.atStartOfDay(ZoneOffset.systemDefault()).toInstant().toEpochMilli();
            // 1575388800000
            log.info("timestamp1 : {}", timestamp1);
    
            // LocalDateTime convert long
            LocalDateTime localDateTime = LocalDateTime.now();
            ZoneOffset offset = ZoneOffset.systemDefault().getRules().getOffset(Instant.now());
            long timestamp2 = localDateTime.toInstant(offset).toEpochMilli();
            // 1575458506749
            log.info("timestamp2 : {}", timestamp2);
    
            // String convert long
            String dateStr = "2019-12-04 19:50:09";
            DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            LocalDateTime parse = LocalDateTime.parse(dateStr, dtf);
            long time = LocalDateTime.from(parse).atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
            // 1575460209000
            log.info("time : {}", time);
        }
    
        @Test
        void testConvertTimestamp() {
            // long convert Timestamp
            long currentTimeMillis = System.currentTimeMillis();
            Timestamp timestamp0 = new Timestamp(currentTimeMillis);
            // 2019-12-04T20:09:48.279+0800
            log.info("timestamp0 : {}", timestamp0);
    
            // LocalDateTime convert Timestamp
            LocalDateTime localDateTime = LocalDateTime.now();
            Timestamp timestamp1 = Timestamp.valueOf(localDateTime);
            // 2019-12-04T20:09:48.287+0800
            log.info("timestamp1 : {}", timestamp1);
    
            // String convert Timestamp
            // 'yyyy-MM-dd HH:mm:ss.SSS'不带'T'
            String dateStr1 = "2019-12-04 19:45:0";
            Timestamp timestamp2 = Timestamp.valueOf(dateStr1);
            // 2019-12-04T19:45:00.000+0800
            log.info("timestamp2 : {}", timestamp2);
    
            String dateStr2 = "2019-12-04 19:45:09";
            Timestamp timestamp3 = Timestamp.valueOf(dateStr2);
            // 2019-12-04T19:45:09.000+0800
            log.info("timestamp3 : {}", timestamp3);
    
            String dateStr3 = "2019-12-04 19:45:09.4";
            Timestamp timestamp4 = Timestamp.valueOf(dateStr3);
            // 2019-12-04T19:45:09.400+0800
            log.info("timestamp4 : {}", timestamp4);
    
            String dateStr4 = "2019-12-04 19:45:09.45";
            Timestamp timestamp5 = Timestamp.valueOf(dateStr4);
            // 2019-12-04T19:45:09.450+0800
            log.info("timestamp5 : {}", timestamp5);
    
            String dateStr5 = "2019-12-04 19:45:09.453";
            Timestamp timestamp6 = Timestamp.valueOf(dateStr5);
            // 2019-12-04T19:45:09.453+0800
            log.info("timestamp6 : {}", timestamp6);
        }
    
        @Test
        void testConvertString() {
            // long convert String
            long time = Instant.now().toEpochMilli();
            DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
            String dateStr1 = dtf.format(LocalDateTime.ofInstant(Instant.ofEpochMilli(time), ZoneId.systemDefault()));
            // 2019-12-04 19:58:04
            log.info("dateStr1 : {}", dateStr1);
    
            // Date convert String
            Date date = new Date();
            String  dateStr2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(date);
            // 2019-12-04 20:26:02.272
            log.info("dateStr2 : {}", dateStr2);
    
            // LocalDateTime convert String
            LocalDateTime localDateTime = LocalDateTime.now();
            String dateStr3 = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS").format(localDateTime);
            // 2019-12-04 20:29:30.424
            log.info("dateStr3 : {}", dateStr3);
    
            // Timestamp convert String
            Timestamp timestamp = new Timestamp(System.currentTimeMillis());
            String dateStr4 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(timestamp);
            // 2019-12-04 20:31:37.580
            log.info("dateStr4 : {}", dateStr4);
            String dateStr5 = timestamp.toString();
            // 2019-12-04 20:31:37.58
            log.info("dateStr5 : {}", dateStr5);
        }
    
        @Test
        void testConvertZoneOffset() {
            assertThrows(ClassCastException.class, () -> {
                ZoneId zoneId = ZoneOffset.systemDefault();
                // zoneId不能直接强转成ZoneOffset
                ZoneOffset zoneOffset = (ZoneOffset) zoneId;
            });
    
            Instant instant = Instant.now();
            ZoneId systemZone = ZoneOffset.systemDefault();
            ZoneOffset zoneOffset1 = systemZone.getRules().getOffset(instant);
            // +08:00
            log.info("zoneOffset1 : {}", zoneOffset1);
        }
    
    
    }