Java：将字符串转换为时间戳

Question

提问by Dimitra Micha

I have an issue while I try to convert a String to a TimeStamp. I have an array that has the date in the format of yyyy-MM-ddand I want to change in the format of yyyy-MM-dd HH:mm:ss.SSS. So, I use this code:

我在尝试将字符串转换为时间戳时遇到问题。我有一个数组，其日期格式为yyyy-MM-dd，我想更改为yyyy-MM-dd HH:mm:ss.SSS. 所以，我使用这个代码：

final String OLD_FORMAT = "yyyy-MM-dd";
final String NEW_FORMAT = "yyyy-MM-dd HH:mm:ss.SSS";
String oldDateString = createdArray[k];
String newDateString;

DateFormat formatter = new SimpleDateFormat(OLD_FORMAT);
Date d = formatter.parse(oldDateString);
((SimpleDateFormat) formatter).applyPattern(NEW_FORMAT);
newDateString = formatter.format(d);
System.out.println(newDateString);

Timestamp ts = Timestamp.valueOf(newDateString);
System.out.println(ts);

and I get the following result.

我得到以下结果。

2009-10-20 00:00:00.000
2009-10-20 00:00:00.0

but when I try to simply do

但是当我试着简单地做

String text = "2011-10-02 18:48:05.123";
ts = Timestamp.valueOf(text);
System.out.println(ts);

I get the right result:

我得到正确的结果：

2011-10-02 18:48:05.123

Do u know what I might be doing wrong? Thanks for the help.

你知道我可能做错了什么吗？谢谢您的帮助。

Answer 1

回答by KhAn SaAb

first convert your date string to datethen convert it to timestampby using following set of line

首先转换您的日期字符串，date然后timestamp使用以下一组行将其转换为

Date date=new Date();
Timestamp timestamp = new Timestamp(date.getTime());//instead of date put your converted date
Timestamp myTimeStamp= timestamp;

Answer 2

回答by ZaoTaoBao

Follow these steps for a correct result:

请按照以下步骤获得正确的结果：

try {
    SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss.SSS");
    Date parsedDate = dateFormat.parse(yourString);
    Timestamp timestamp = new java.sql.Timestamp(parsedDate.getTime());
} catch(Exception e) { //this generic but you can control another types of exception
    // look the origin of excption 
}

Please note that .parse(String)might throw a ParseException.

请注意，.parse(String)可能会抛出一个ParseException.

Answer 3

回答by Suresh U

can you try it once...

你能不能试一次...

String dob="your date String";
String dobis=null;
final DateFormat df = new SimpleDateFormat("yyyy-MMM-dd");
final Calendar c = Calendar.getInstance();
try {
    if(dob!=null && !dob.isEmpty() && dob != "")
    {
    c.setTime(df.parse(dob));
    int month=c.get(Calendar.MONTH);
    month=month+1;
    dobis=c.get(Calendar.YEAR)+"-"+month+"-"+c.get(Calendar.DAY_OF_MONTH);
    }

}

Answer 4

回答by solver

I'm sure the solution is that your oldDateString is something like "2009-10-20". Obviously this does not contain any time data lower than days. If you format this string with your new formatter where should it get the minutes, seconds and milliseconds from?

我确定解决方案是您的 oldDateString 类似于“2009-10-20”。显然，这不包含任何低于天的时间数据。如果你用你的新格式化程序格式化这个字符串，它应该从哪里获取分钟、秒和毫秒？

So the result is absolutely correct: 2009-10-20 00:00:00.000

所以结果是绝对正确的：2009-10-20 00:00:00.000

What you'll need to solve this, is the original timestamp (incl. time data) before your first formatting.

您需要解决这个问题，是您第一次格式化之前的原始时间戳（包括时间数据）。

Answer 5

回答by Harsh

import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Util {
  public static Timestamp convertStringToTimestamp(String strDate) {
    try {
      DateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
       // you can change format of date
      Date date = formatter.parse(strDate);
      Timestamp timeStampDate = new Timestamp(date.getTime());

      return timeStampDate;
    } catch (ParseException e) {
      System.out.println("Exception :" + e);
      return null;
    }
  }
}

Answer 6

回答by Mahesh Narwade

DateFormat formatter;
formatter = new SimpleDateFormat("dd/MM/yyyy");
Date date = (Date) formatter.parse(str_date);
java.sql.Timestamp timeStampDate = new Timestamp(date.getTime());

Answer 7

回答by Akshay Misal

DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");

Date date = formatter.parse(dateString);

Timestamp timestamp = new Timestamp(date.getTime());

System.out.println(timestamp);

Answer 8

回答by Ole V.V.

I should like to contribute the modern answer. When this question was asked in 2013, using the Timestampclass was right, for example for storing a date-time into your database. Today the class is long outdated. The modern Java date and time API came out with Java 8 in the spring of 2014, three and a half years ago. I recommend you use this instead.

我想贡献现代答案。当在 2013 年提出这个问题时，使用Timestamp该类是正确的，例如将日期时间存储到您的数据库中。今天的课程已经过时了。现代 Java 日期和时间 API 于 2014 年春季（三年半前）随 Java 8 发布。我建议你改用这个。

Depending on your situation an exact requirements, there are two natural replacements for Timestamp:

根据您的具体要求，有两种自然替代品Timestamp：

Instantis a point on the time-line. For most purposes I would consider it safest to use this. An Instantis independent of time zone and will usually work well even in situations where your client device and your database server run different time zones.
LocalDateTimeis a date and time of day without time zone, like 2011-10-02 18:48:05.123 (to quote the question).

Instant是时间线上的一个点。对于大多数目的，我认为使用它是最安全的。AnInstant独立于时区，即使在您的客户端设备和数据库服务器运行不同时区的情况下，它通常也能很好地工作。
LocalDateTime是没有时区的日期和时间，例如 2011-10-02 18:48:05.123 （引用问题）。

A modern JDBC driver (JDBC 4.2 or higher) and other modern tools for database access will be happy to store either an Instantor a LocalDateTimeinto your database column of datatype timestamp. Both classes and the other date-time classes I am using in this answer belong to the modern API known as java.timeor JSR-310.

现代 JDBC 驱动程序（JDBC 4.2 或更高版本）和其他用于数据库访问的现代工具将很乐意将 anInstant或 a存储LocalDateTime到数据类型的数据库列中timestamp。我在此答案中使用的类和其他日期时间类都属于称为java.timeJSR-310的现代 API 。

It's easiest to convert your string to LocalDateTime, so let's take that first:

将字符串转换为最容易LocalDateTime，所以让我们先来看看：

    DateTimeFormatter formatter
            = DateTimeFormatter.ofPattern("uuuu-MM-dd HH:mm:ss.SSS");
    String text = "2011-10-02 18:48:05.123";
    LocalDateTime dateTime = LocalDateTime.parse(text, formatter);
    System.out.println(dateTime);

This prints

这打印

2011-10-02T18:48:05.123

If your string was in yyyy-MM-dd format, instead do:

如果您的字符串是 yyyy-MM-dd 格式，请改为：

    String text = "2009-10-20";
    LocalDateTime dateTime = LocalDate.parse(text).atStartOfDay();
    System.out.println(dateTime);

This prints

这打印

2009-10-20T00:00

Or still better, take the output from LocalDate.parse()and store it into a database column of datatype date.

或者更好的是，获取输出LocalDate.parse()并将其存储到数据类型的数据库列中date。

In both cases the procedure for converting from a LocalDateTimeto an Instantis:

在这两种情况下，从 a 转换LocalDateTime为 an 的过程Instant是：

    Instant ts = dateTime.atZone(ZoneId.systemDefault()).toInstant();
    System.out.println(ts);

I have specified a conversion using the JVM's default time zone because this is what the outdated class would have used. This is fragile, though, since the time zone setting may be changed under our feet by other parts of your program or by other programs running in the same JVM. If you can, specify a time zone in the region/cityformat instead, for example:

我已经使用 JVM 的默认时区指定了一个转换，因为这是过时的类将使用的。但是，这很脆弱，因为程序的其他部分或在同一 JVM 中运行的其他程序可能会更改时区设置。如果可以，请改为以地区/城市格式指定时区，例如：

    Instant ts = dateTime.atZone(ZoneId.of("Europe/Athens")).toInstant();

Answer 9

回答by Yuliia Ashomok

The easy way to convert String to java.sql.Timestamp:

将 String 转换为 java.sql.Timestamp 的简单方法：

Timestamp t = new Timestamp(DateUtil.provideDateFormat().parse("2019-01-14T12:00:00.000Z").getTime());

DateUtil.java:

DateUtil.java：

import java.text.SimpleDateFormat;
import java.util.TimeZone;

public interface DateUtil {

  String ISO_DATE_FORMAT_ZERO_OFFSET = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
  String UTC_TIMEZONE_NAME = "UTC";

  static SimpleDateFormat provideDateFormat() {
    SimpleDateFormat simpleDateFormat = new SimpleDateFormat(ISO_DATE_FORMAT_ZERO_OFFSET);
    simpleDateFormat.setTimeZone(TimeZone.getTimeZone(UTC_TIMEZONE_NAME));
    return simpleDateFormat;
  }
}

Answer 10

回答by KeyMaker00

Just for the sake of completeness, here is a solution with lambda and method reference:

为了完整起见，这里有一个带有 lambda 和方法参考的解决方案：

ISO format?

ISO格式？

Description: The following method

说明：以下方法

converts a Stringwith the pattern yyyy-MM-ddinto a Timestamp, if a valid input is given,
returns a null, if a nullvalue is given,
throws a DateTimeParseException, if an invalid input is given

如果给出有效输入，则将String带有模式的yyyy-MM-dda转换为 a Timestamp，
返回 a null，如果null给定值，
DateTimeParseException如果给出无效输入，则抛出 a

Code:

代码：

static Timestamp convertStringToTimestamp(String strDate) {
    return Optional.ofNullable(strDate) // wrap the String into an Optional
                   .map(str -> LocalDate.parse(str).atStartOfDay()) // convert into a LocalDate and fix the hour:minute:sec to 00:00:00
                   .map(Timestamp::valueOf) // convert to Timestamp
                   .orElse(null); // if no value is present, return null
}

Validation: This method can be tested with those unit tests: (with Junit5and Hamcrest)

验证：可以使用这些单元测试来测试此方法：（使用Junit5和Hamcrest）

@Test
void convertStringToTimestamp_shouldReturnTimestamp_whenValidInput() {
    // given
    String strDate = "2020-01-30";

    // when
    final Timestamp result = convertStringToTimestamp(strDate);

    // then
    final LocalDateTime dateTime = LocalDateTime.ofInstant(result.toInstant(), ZoneId.systemDefault());
    assertThat(dateTime.getYear(), is(2020));
    assertThat(dateTime.getMonthValue(), is(1));
    assertThat(dateTime.getDayOfMonth(), is(30));
}

@Test
void convertStringToTimestamp_shouldReturnTimestamp_whenInvalidInput() {
    // given
    String strDate = "7770-91-30";

    // when, then
    assertThrows(DateTimeParseException.class, () -> convertStringToTimestamp(strDate));
}

@Test
void convertStringToTimestamp_shouldReturnTimestamp_whenNullInput() {
    // when
    final Timestamp result = convertStringToTimestamp(null);

    // then
    assertThat(result, is(nullValue()));
}

Another format?

另一种格式？

Usually, the string to parse comes with another format. A way to deal with it is to use a formatter to convert it to another format. Here is an example:

通常，要解析的字符串带有另一种格式。处理它的一种方法是使用格式化程序将其转换为另一种格式。下面是一个例子：

Input: 20200130 11:30

输入： 20200130 11:30

Pattern: yyyyMMdd HH:mm

图案： yyyyMMdd HH:mm

Output: Timestamp of this input

输出：此输入的时间戳

Code:

代码：

static Timestamp convertStringToTimestamp(String strDate) {
    final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd HH:mm");
    return Optional.ofNullable(strDate) //
                   .map(str -> LocalDateTime.parse(str, formatter))
                   .map(Timestamp::valueOf) //
                   .orElse(null);
}

Test:

测试：

@Test
void convertStringToTimestamp_shouldReturnTimestamp_whenValidInput() {
    // given
    String strDate = "20200130 11:30";

    // when
    final Timestamp result = convertStringToTimestamp(strDate);

    // then
    final LocalDateTime dateTime = LocalDateTime.ofInstant(result.toInstant(), ZoneId.systemDefault());
    assertThat(dateTime.getYear(), is(2020));
    assertThat(dateTime.getMonthValue(), is(1));
    assertThat(dateTime.getDayOfMonth(), is(30));
    assertThat(dateTime.getHour(), is(11));
    assertThat(dateTime.getMinute(), is(30));
}

Java：将字符串转换为时间戳

提问by Dimitra Micha

回答by KhAn SaAb

回答by ZaoTaoBao

回答by Suresh U

回答by solver

回答by Harsh

回答by Mahesh Narwade

回答by Akshay Misal

回答by Ole V.V.

回答by Yuliia Ashomok

回答by KeyMaker00

ISO format?

ISO格式？

Another format?

另一种格式？

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Java：将字符串转换为时间戳

提问by Dimitra Micha

回答by KhAn SaAb

回答by ZaoTaoBao

回答by Suresh U

回答by solver

回答by Harsh

回答by Mahesh Narwade

回答by Akshay Misal

回答by Ole V.V.

回答by Yuliia Ashomok

回答by KeyMaker00

ISO format?

ISO格式？

Another format?

另一种格式？

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