使用 simpleDateFormat java 解析日期

我想将字符串解析为日期，但获得的日期不正确。我的代码是这样的：

SimpleDateFormat df = new SimpleDateFormat("dd-MMM-yy hh.mm.ss.S a");
date1 = df.parse("17-DEC-19 05.40.39.364000000 PM");

但 date1 是： 2019 年 12 月 21 日星期六 22:47:19 IRST

我需要日期：* 12 月 17 日 17:40:39 IRST 2019

The SimpleDateFormat精度不超过毫秒（.SSS).

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class Main {
    public static void main(String[] args) throws ParseException {
        SimpleDateFormat df = new SimpleDateFormat("dd-MMM-yy hh.mm.ss.SSS a", Locale.ENGLISH);
        Date date1 = df.parse("17-DEC-19 05.40.39.364 PM");
        System.out.println(date1);
    }
}

Output:

Tue Dec 17 17:40:39 GMT 2019

Note that the java.util date-time API and their formatting API, SimpleDateFormat are outdated and error-prone. It is recommended to stop using them completely and switch to the modern date-time API^* .

使用现代日期时间 API：

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

public class Main {
    public static void main(String[] args)  {
        DateTimeFormatter df = new DateTimeFormatterBuilder()
                .parseCaseInsensitive() // For case-insensitive (e.g. AM/am) parsing
                .appendPattern("dd-MMM-yy hh.mm.ss.n a")
                .toFormatter(Locale.ENGLISH);
        
        LocalDateTime ldt = LocalDateTime.parse("17-DEC-19 05.40.39.364000000 PM", df);
        System.out.println(ldt);
    }
}

Output:

2019-12-17T17:40:39.364

了解有关现代日期时间 API 的更多信息路线：日期时间.

^{* For any reason, if you have to stick to Java 6 or Java 7, you can use ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and How to use ThreeTenABP in Android Project.}