相关疑难解决方法(0)

我对Java 8 Time API中的日期解析感到有点气馁.

以前我可以轻松写:

String date = "04.2013";
DateFormat df = new SimpleDateFormat("MM.yyyy");
Date d = df.parse(date);

但是现在如果我使用LocalDate并像这样做:

String date = "04.2013";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MM.yyyy");
LocalDate ld = LocalDate.parse(date, formatter);

我收到一个例外:

java.time.format.DateTimeParseException: Text '04' could not be parsed at index 0
java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1948)
java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1850)
java.time.LocalDate.parse(LocalDate.java:400)
java.time.LocalDate.parse(LocalDate.java:385)
com.luxoft.ath.controllers.JsonController.region(JsonController.java:38)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:483)
org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:852)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

如果我将字符串格式更改为"yyyy-MM-dd",即使没有格式化程序,一切也能正常工作:

String date = "2013-04-12";
LocalDate …

我有一段代码工作正常,现在不知何故不起作用.

我正在读取csv文件,并在读取格式的时间字段时出错4:38.

我抛出异常的代码是:

LocalTime.parse("4:38", DateTimeFormatter.ofPattern("HH:mm"))

我也试过"H:mm"或者"H:m"为模式但它抛出同样的异常:Text '4:38' could not be parsed at index 0.知道为什么它会在小时数引发异常吗？

我使用的是Java 8.

我对 Java 8 还很陌生，所以这个问题可能有一个明显的答案，但在阅读了其他类似的 SO 问题后，我找不到任何导致我的问题的相似之处。

这是我的班级：

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class LocalDateTimeIssue {

    public static void main(String[] args) {
        String dateTimeString = "18-04-2019 12:14:46";
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("dd-MM-yyyy hh:mm:ss", Locale.US);
        LocalDateTime ldt = LocalDateTime.parse(dateTimeString , dtf);
        System.out.println(ldt.getSecond());
    }

}

这会引发以下异常：

Exception in thread "main" java.time.format.DateTimeParseException: Text '18-04-2019 12:14:46' could not be parsed: Unable to obtain LocalDateTime from TemporalAccessor: {MilliOfSecond=0, MinuteOfHour=14, HourOfAmPm=0, NanoOfSecond=0, MicroOfSecond=0, SecondOfMinute=46},ISO resolved to 2019-04-18 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) …