问题
Is there any way to convert a date String to LocalDateTime where the format "yyyy-MM-dd" ?
If I try this:
DateTimeFormatter DATEFORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd");
LocalDateTime ldt = LocalDateTime.parse(string, DATEFORMATTER);
I got this exception:
java.time.format.DateTimeParseException: Text '2017-03-13' could not be parsed: Unable to obtain LocalDateTime from TemporalAccessor: {},ISO resolved to 2017-03-13 of type java.time.format.Parsed
at java.time.format.DateTimeFormatter.createError(DateTimeFormatter.java:1920)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1855)
at java.time.LocalDateTime.parse(LocalDateTime.java:492)
at hu.npsh.workforce.utils.Util.stringToLocalDateTime(Util.java:284)
at hu.npsh.workforce.utils.util.StringLocalDateTimeConversionTest.stringToLocalDateTimeTest(StringLocalDateTimeConversionTest.java:35)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: java.time.DateTimeException: Unable to obtain LocalDateTime from TemporalAccessor: {},ISO resolved to 2017-03-13 of type java.time.format.Parsed
at java.time.LocalDateTime.from(LocalDateTime.java:461)
at java.time.format.Parsed.query(Parsed.java:226)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
... 26 more
Caused by: java.time.DateTimeException: Unable to obtain LocalTime from TemporalAccessor: {},ISO resolved to 2017-03-13 of type java.time.format.Parsed
at java.time.LocalTime.from(LocalTime.java:409)
at java.time.LocalDateTime.from(LocalDateTime.java:457)
... 28 more
I know that the main problem, that the pattern does not contain the hour and the minute..
But what if I want a create a method what gets a String and a DateTimeFormatter and I want to return with LocalDateTime
Is there a correct, nice solution?
EDIT:
My goal, making a method what get a String and a DateTimeFormatter
And returns with a LocalDateTime.
The Pattern can be anything (what is valid).
回答1:
Use LocalDate to create a localDate and then you can add the timepart if you need it:
DateTimeFormatter DATEFORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd");
LocalDate ld = LocalDate.parse("2017-03-13", DATEFORMATTER);
LocalDateTime ldt = LocalDateTime.of(ld, LocalDateTime.now().toLocalTime());
System.out.println(ldt);
or LocalDateTime
ldt = LocalDateTime.of(ld, LocalDateTime.MIN.toLocalTime());
if you just need an empty timepart
EDIT:
Look at this solution with this you can build your dynamic parser:
DateTimeFormatter DATEFORMATTER1 = DateTimeFormatter.ofPattern("yyyy-MM-dd");
DateTimeFormatter DATEFORMATTER = new DateTimeFormatterBuilder().append(DATEFORMATTER1)
.parseDefaulting(ChronoField.HOUR_OF_DAY, 0)
.parseDefaulting(ChronoField.MINUTE_OF_HOUR, 0)
.parseDefaulting(ChronoField.SECOND_OF_MINUTE, 0)
.toFormatter();
//DateTimeFormatter DATEFORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd");
LocalDateTime ldt = LocalDateTime.parse("2017-03-13", DATEFORMATTER);
回答2:
You can not convert "2017-03-13" to a LocalDateTime since there is no time information in the string, only date. You can convert it to a LocalDate
DateTimeFormatter dateformatter = DateTimeFormatter.ofPattern("yyyy-MM-dd");
LocalDate ld = LocalDate.parse("2017-03-13", dateformatter);
after this we can covert it to LocalDateTime
LocalDateTime ldt = ld.atStartOfDay();
回答3:
For start of the day you can use:
LocalDate.parse("2017-10-18", DateTimeFormatter.ofPattern("yyyy-MM-dd"))
.atStartOfDay().atOffset(ZoneOffset.UTC).format(DateTimeFormatter.ISO_DATE_TIME)
For end of the day you can use:
LocalDate.parse("2017-10-18", DateTimeFormatter.ofPattern("yyyy-MM-dd"))
.atStartOfDay().plusHours(23).plusMinutes(59).plusSeconds(59).atOffset(ZoneOffset.UTC).format(DateTimeFormatter.ISO_DATE_TIME)
For localDateTime you can use:
LocalDate.parse("2017-10-18", DateTimeFormatter.ofPattern("yyyy-MM-dd")).atTime(LocalTime.now())
.atOffset(ZoneOffset.UTC).format(DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'"))
Result:
2017-10-18T00:00:00Z
2017-10-18T23:59:59Z
2017-10-18T14:45:35Z
回答4:
How about a one liner?
LocalDateTime.parse("2017-03-13" + " 00:00", DateTimeFormatter.ofPattern("yyyy-MM-dd hh:mm"));
回答5:
Use Joda-Time-XX.jar it has DateTimeFormatter to convert date to date time format. Either you can provide date time in (yyyy-MM-dd HH:mm:ss format) or date alone. In both the cases you will get date and time.
DateTimeFormatter dateTimeFormatter = DateTimeFormat.forPattern("yyyy-MM-dd");
DateTime dateTime = dateTimeFormatter.parseDateTime(date);
来源：https://stackoverflow.com/questions/42763103/convert-string-yyyy-mm-dd-to-localdatetime