localDateTime和Date

该配置类处理全局日期格式化。

和 @JsonFormat一起使用时，@JsonFormat优先级更高。

@Configuration
public class LocalDateTimeSerializerConfig {

    @Value(value = "${spring.jackson.date-format:yyyy-MM-dd HH:mm:ss}")
    private String pattern;

    @Bean
    public LocalDateTimeSerializer localDateTimeDeserializer() {
        return new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(pattern));
    }

    @Bean
    public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
        return builder -> builder.serializerByType(LocalDateTime.class, localDateTimeDeserializer());
    }
}

---

①：获取当前时间对象

LocalDateTime now = LocalDateTime.now();
Date now = new Date();

②：获取年月日

LocalDate.now()；

③：获取时分秒

LocalTime.now()

④:LocalDateTime获取毫秒数

//获取秒数
Long second = LocalDateTime.now().toEpochSecond(ZoneOffset.of("+8"));
//获取毫秒数
Long milliSecond = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).toEpochMilli();
  
LocalDateTime与String互转
//时间转字符串格式化
 DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMddHHmmssSSS");
 String dateTime = LocalDateTime.now(ZoneOffset.of("+8")).format(formatter);
  
//字符串转时间
String dateTimeStr = "2018-07-28 14:11:15";
DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
LocalDateTime dateTime = LocalDateTime.parse(dateTimeStr, df);

 

⑤:Date与LocalDateTime互转

//将java.util.Date 转换为java8 的java.time.LocalDateTime,默认时区为东8区
 public static LocalDateTime dateConvertToLocalDateTime(Date date) {
  return date.toInstant().atOffset(ZoneOffset.of("+8")).toLocalDateTime();
 }
  
  
 //将java8 的 java.time.LocalDateTime 转换为 java.util.Date，默认时区为东8区
 public static Date localDateTimeConvertToDate(LocalDateTime localDateTime) {
  return Date.from(localDateTime.toInstant(ZoneOffset.of("+8")));

 

⑥:LocalDateTime转为自定义的时间格式的字符串

public static String getDateTimeAsString(LocalDateTime localDateTime, String format) {
 DateTimeFormatter formatter = DateTimeFormatter.ofPattern(format);
 return localDateTime.format(formatter);
}

 

⑦:某时间字符串转为自定义时间格式的LocalDateTime

public static LocalDateTime parseStringToDateTime(String time, String format) {
 DateTimeFormatter df = DateTimeFormatter.ofPattern(format);
 return LocalDateTime.parse(time, df);
}

 

⑧:long类型的timestamp转为LocalDateTime

public static LocalDateTime getDateTimeOfTimestamp(long timestamp) {
 Instant instant = Instant.ofEpochMilli(timestamp);
 ZoneId zone = ZoneId.systemDefault();
 return LocalDateTime.ofInstant(instant, zone);
}

 

⑨:LocalDateTime转为long类型的timestamp

public static long getTimestampOfDateTime(LocalDateTime localDateTime) {
 ZoneId zone = ZoneId.systemDefault();
 Instant instant = localDateTime.atZone(zone).toInstant();
 return instant.toEpochMilli();
}