这里我们使用JShell交互式编程环境
没有安装JShell的小伙伴可以参考我的文章Mac terminal终端使用JShell

LocalDate&LocalTime&LocalDateTime与String类型之间的转换

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

LocalDate转String类型

jshell> LocalDate ld = LocalDate.now()
ld ==> 2019-10-25
jshell> DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd");
dtf ==> Value(YearOfEra,4,19,EXCEEDS_PAD)'-'Value(MonthOfYear,2)'-'Value(DayOfMonth,2)
jshell> String dateNow = ld.format(dtf);
dateNow ==> "2019-10-25"

LocalTime转String类型

jshell> LocalTime lt = LocalTime.now();
lt ==> 13:13:14.744389
jshell> DateTimeFormatter dtf = DateTimeFormatter.ofPattern("HH:mm:ss:SSS");
dtf ==> Value(HourOfDay,2)':'Value(MinuteOfHour,2)':'Valu ... Fraction(NanoOfSecond,3,3)
jshell> String dateNow = lt.format(dtf);
dateNow ==> "13:13:14:744"

LocalDateTime转String类型

jshell> LocalDateTime ldt = LocalDateTime.now();
ldt ==> 2019-10-25T13:16:54.381700
jshell> DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss:SSS");
dtf ==> Value(YearOfEra,4,19,EXCEEDS_PAD)'-'Value(MonthOf ... Fraction(NanoOfSecond,3,3)
jshell> String dateNow = ldt.format(dtf);
dateNow ==> "2019-10-25 13:16:54:381"