String类型转localDate,date转localDate的实现代码

Date dates = new SimpleDateFormat(“yyyyMM”).parse(cycle);
Instant instant = dates.toInstant();
ZoneId zoneId = ZoneId.systemDefault();
LocalDate localDate = instant.atZone(zoneId).toLocalDate();

DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
LocalDateTime time = LocalDateTime.now();
String localTime = df.format(time);
LocalDateTime ldt = LocalDateTime.parse("2018-06-01 10:12:05",df);
System.out.println("LocalDateTime转成String类型的时间："+localTime);
System.out.println("String类型的时间转成LocalDateTime："+ldt);

java.util.Date date = new java.util.Date();
 Instant instant = date.toInstant();
 ZoneId zone = ZoneId.systemDefault();
 LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, zone);

LocalDateTime localDateTime = LocalDateTime.now();
 ZoneId zone = ZoneId.systemDefault();
 Instant instant = localDateTime.atZone(zone).toInstant();
 java.util.Date date = Date.from(instant);

LocalDate localDate = LocalDate.now();
 ZoneId zone = ZoneId.systemDefault();
 Instant instant = localDate.atStartOfDay().atZone(zone).toInstant();
 java.util.Date date = Date.from(instant);

LocalDateTime now = LocalDateTime.now();
 //明天
 LocalDateTime plusDays = now.plusDays(1);
 //昨天
 LocalDateTime plusDays2 = now.plusDays(-1);
 //还有时分等同理

Duration duration = Duration.between(localDateTime,localDateTime4);
duration.toDays();
duration.toHours();
duration.toMinutes();
Period period2 = Period.between(localDateTime.toLocalDate(),localDateTime4.toLocalDate());
period2.getYears();
period2.getMonths();
period2.toTotalMonths();

String time = "2018-08-09 11:20:45";
  DateTimeFormatter dtf = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss");
  LocalDateTime localTime = LocalDateTime.parse(time, dtf);
  LocalDateTime startTime = LocalDate.now().atTime(0, 0, 0);
  LocalDateTime endTime = LocalDate.now().atTime(23, 59, 59);
  LocalDateTime startYesterday = LocalDate.now().plusDays(-1).atTime(0, 0, 0);
  LocalDateTime endYesterday = LocalDate.now().plusDays(-1).atTime(23, 59, 59);
 
  //如果小于昨天的开始日期
  if (localTime.isBefore(startYesterday)) {
   System.out.println("时间是过去");
  }
  //时间是昨天
  if (localTime.isAfter(startYesterday) && localTime.isBefore(endYesterday)) {
   System.out.println("时间是昨天");
  }
  //如果大于今天的开始日期，小于今天的结束日期
  if (localTime.isAfter(startTime) && localTime.isBefore(endTime)) {
   System.out.println("时间是今天");
  }
  //如果大于今天的结束日期
  if (localTime.isAfter(endTime)) {
   System.out.println("时间是未来");
  }
 }

LocalDate start = LocalDate.of(2019, 4, 29);
  LocalDate end = LocalDate.of(2019, 7, 29);
  do {
   System.out.println(start);
   start = start.plusDays(1);
  } while (start.toEpochDay() <= end.toEpochDay());

LocalDate start = LocalDate.now().plusDays(-7);
  LocalDate end = LocalDate.now();
  do {
   start.atStartOfDay().atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();        
   start.atTime(LocalTime.MAX).atZone(ZoneId.systemDefault())
    .toInstant().toEpochMilli();
   start = start.plusDays(1);
  } while (start.toEpochDay() <= end.toEpochDay());