如何在 android 中获取当前日期和时间并将其存储到字符串中

Question

目前我正在使用下面的代码：

String  currentDateTimeString = DateFormat.getDateTimeInstance()
                        .format(new Date());

由此我得到以下格式的输出 -

Jun 5, 2015 1:15:29 PM

但现在我想要以下格式的输出-

2015-06-05 08:10:40

它可以是 12 或 24 小时格式。

我想要使用上述日期时间格式的当前日期时间。

我已经使用了 SimpleDateFormat 但我无法获得以上内容当前日期和时间的日期时间格式

那么，我该如何实现呢？

Answer 1

Update 01/Sept/2020 - Sample Kotlin DateUtilExtensions using Java SE 8

@file:JvmName("DateUtilExtensions")

package com.intigral.jawwytv.util.extensions

import android.text.TextUtils
import android.text.format.DateUtils
import java.text.ParseException
import java.text.SimpleDateFormat
import java.time.Instant
import java.time.LocalDate
import java.time.LocalDateTime
import java.time.ZoneId
import java.time.ZoneOffset
import java.time.format.DateTimeFormatter
import java.util.Date
import java.util.Locale
import java.util.TimeZone

const val PATTERN_YEAR = "yyyy"
const val PATTERN_MONTH = "MMM"
const val PATTERN_MONTH_FULL = "MMMM"
const val PATTERN_DAY_OF_MONTH = "dd"
const val PATTERN_DAY_OF_WEEK = "EEEE"
const val PATTERN_TIME = "hh:mm a"
const val PATTERN_TIME_24H = "HH:mm"
const val PATTERN_SERVER_DATE = "yyyy-MM-dd"
const val PATTERN_SERVER_DATE_TIME = "yyyy-MM-dd HH:mm:ss"
const val PATTERN_START_WITH_MONTH = "MMM dd , yyyy"
const val PATTERN_START_WITH_MONTH_NO_YEAR = "MMMM dd"
const val PATTERN_START_WITH_DATE_NO_YEAR = "dd MMMM"
const val PATTERN_START_WITH_MONTH_SHORT_NO_YEAR = "MMM dd"
const val PATTERN_START_WITH_MONTH_WITH_TIME = "MMM dd, yyyy HH:mm:ss"
const val PATTERN_START_WITH_MONTH_SMALL_NO_YEAR = "MMM dd"

fun formatDate(pattern: String): String {
    val localDateTime = LocalDateTime.now()
    return localDateTime.format(DateTimeFormatter.ofPattern(pattern))
}

fun formatDate(localDateTime: LocalDateTime, pattern: String): String =
    localDateTime.format(DateTimeFormatter.ofPattern(pattern))

fun formatDate(timeInMills: Long?, pattern: String): String =
    LocalDateTime.ofInstant(Instant.ofEpochMilli(timeInMills ?: 0), ZoneId.systemDefault())
        .format(DateTimeFormatter.ofPattern(pattern))

fun todayToEpochMilli() =
    LocalDate.now().atStartOfDay(ZoneId.systemDefault()).toInstant().toEpochMilli()

fun isDateEqual(dateInMills: Long?, dateInMillsOther: Long?): Boolean {
    val systemDefault = ZoneOffset.systemDefault()
    val date = Instant.ofEpochMilli(dateInMills ?: 0).atZone(systemDefault).toLocalDate()
    val otherDate =
        Instant.ofEpochMilli(dateInMillsOther ?: 0).atZone(systemDefault).toLocalDate()
    return date.isEqual(otherDate)
}

fun convertDateString(inputPattern: String, outputPattern: String, stringDate: String): String? {
    val originalFormat = SimpleDateFormat(inputPattern, Locale.getDefault())
    val targetFormat = SimpleDateFormat(outputPattern, Locale.getDefault())
    val requiredFormat = originalFormat.parse(stringDate)
    return requiredFormat?.let { targetFormat.format(requiredFormat) }
}

fun getRelativeTimeSpanString(
    dateString: String,
    format: String = PATTERN_SERVER_DATE_TIME
): String? {
    if (!TextUtils.isEmpty(dateString)) {
        val simpleDateFormat = SimpleDateFormat(format, Locale.getDefault())
        simpleDateFormat.timeZone = TimeZone.getTimeZone(ZoneOffset.UTC)
        var date: Date? = null
        try {
            date = simpleDateFormat.parse(dateString)
        } catch (e: ParseException) {
            e.printStackTrace()
        }

        val epochTime = date!!.time

        val relTime = DateUtils.getRelativeTimeSpanString(
            epochTime,
            System.currentTimeMillis(),
            DateUtils.SECOND_IN_MILLIS
        )

        return relTime.toString()
    }
    return dateString
}

Initial Answer - use SimpleDateFormat

Date today = new Date();
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss a");
String dateToStr = format.format(today);
System.out.println(dateToStr);

Answer 2

使用这个方法

    public static String currentDate() {
    DateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy");
    // get current date time with Date()
    Date date = new Date();
    // System.out.println(dateFormat.format(date));
    // don't print it, but save it!
    return dateFormat.format(date);
}

根据您的

更改日期时间格式

Answer 3

简单日期格式化程序的解决方案：

   Date todaysdate = new Date();
   SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
   String date = format.format(todaysdate);
   System.out.println(date);

Answer 4

简单理解为， SimpleDateFormat.getDateTimeInstance().format(新日期());

除了getDateTimeInstance，您还可以使用 getDateInstance() 和 getTimeInstance().

如何在 android 中获取当前日期和时间并将其存储到字符串中

How can i get current date and time in android and store it into string

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