java - 将日期字符串解析为 java.util.Date 时出现非法模式字符 'T'

Question

我有一个日期字符串，我想使用 java Date API 将其解析为正常日期，以下是我的代码:

public static void main(String[] args) {
    String date="2010-10-02T12:23:23Z";
    String pattern="yyyy-MM-ddThh:mm:ssZ";
    SimpleDateFormat sdf=new SimpleDateFormat(pattern);
    try {
        Date d=sdf.parse(date);
        System.out.println(d.getYear());
    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

但是我遇到了一个异常:java.lang.IllegalArgumentException: Illegal pattern character 'T'

所以我想知道我是否必须拆分字符串并手动解析它？

顺便说一句，我试图在 T 的两侧添加一个单引号字符:

String pattern="yyyy-MM-dd'T'hh:mm:ssZ";

它也不起作用。

Answer 1

Java 8 及更高版本的更新

您现在可以简单地执行 Instant.parse("2015-04-28T14:23:38.521Z") 并立即得到正确的东西，特别是因为您应该使用 Instant 而不是带有最新版本 Java 的损坏的 java.util.Date。

您也应该使用 DateTimeFormatter 而不是 SimpleDateFormatter。

原答案:

The explanation below is still valid as as what the format represents. But it was written before Java 8 was ubiquitous so it uses the old classes that you should not be using if you are using Java 8 or higher.

这适用于带有尾随 Z 的输入，如下所示:

In the pattern the T is escaped with ' on either side.

The pattern for the Z at the end is actually XXX as documented in the JavaDoc for SimpleDateFormat, it is just not very clear on actually how to use it since Z is the marker for the old TimeZone information as well.

Q2597083.java

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;

public class Q2597083
{
    /**
     * All Dates are normalized to UTC, it is up the client code to convert to the appropriate TimeZone.
     */
    public static final TimeZone UTC;

    /**
     * @see <a href="http://en.wikipedia.org/wiki/ISO_8601#Combined_date_and_time_representations">Combined Date and Time Representations</a>
     */
    public static final String ISO_8601_24H_FULL_FORMAT = "yyyy-MM-dd'T'HH:mm:ss.SSSXXX";

    /**
     * 0001-01-01T00:00:00.000Z
     */
    public static final Date BEGINNING_OF_TIME;

    /**
     * 292278994-08-17T07:12:55.807Z
     */
    public static final Date END_OF_TIME;

    static
    {
        UTC = TimeZone.getTimeZone("UTC");
        TimeZone.setDefault(UTC);
        final Calendar c = new GregorianCalendar(UTC);
        c.set(1, 0, 1, 0, 0, 0);
        c.set(Calendar.MILLISECOND, 0);
        BEGINNING_OF_TIME = c.getTime();
        c.setTime(new Date(Long.MAX_VALUE));
        END_OF_TIME = c.getTime();
    }

    public static void main(String[] args) throws Exception
    {

        final SimpleDateFormat sdf = new SimpleDateFormat(ISO_8601_24H_FULL_FORMAT);
        sdf.setTimeZone(UTC);
        System.out.println("sdf.format(BEGINNING_OF_TIME) = " + sdf.format(BEGINNING_OF_TIME));
        System.out.println("sdf.format(END_OF_TIME) = " + sdf.format(END_OF_TIME));
        System.out.println("sdf.format(new Date()) = " + sdf.format(new Date()));
        System.out.println("sdf.parse(\"2015-04-28T14:23:38.521Z\") = " + sdf.parse("2015-04-28T14:23:38.521Z"));
        System.out.println("sdf.parse(\"0001-01-01T00:00:00.000Z\") = " + sdf.parse("0001-01-01T00:00:00.000Z"));
        System.out.println("sdf.parse(\"292278994-08-17T07:12:55.807Z\") = " + sdf.parse("292278994-08-17T07:12:55.807Z"));
    }
}

产生以下输出:

sdf.format(BEGINNING_OF_TIME) = 0001-01-01T00:00:00.000Z
sdf.format(END_OF_TIME) = 292278994-08-17T07:12:55.807Z
sdf.format(new Date()) = 2015-04-28T14:38:25.956Z
sdf.parse("2015-04-28T14:23:38.521Z") = Tue Apr 28 14:23:38 UTC 2015
sdf.parse("0001-01-01T00:00:00.000Z") = Sat Jan 01 00:00:00 UTC 1
sdf.parse("292278994-08-17T07:12:55.807Z") = Sun Aug 17 07:12:55 UTC 292278994