这是一个人类可读的时间戳，可以用在文件名中， 以防有人需要和我一样的东西:

package com.example.xyz;

import android.text.format.Time;

/**
 * Clock utility.
 */
public class Clock {

    /**
     * Get current time in human-readable form.
     * @return current time as a string.
     */
    public static String getNow() {
        Time now = new Time();
        now.setToNow();
        String sTime = now.format("%Y_%m_%d %T");
        return sTime;
    }
    /**
     * Get current time in human-readable form without spaces and special characters.
     * The returned value may be used to compose a file name.
     * @return current time as a string.
     */
    public static String getTimeStamp() {
        Time now = new Time();
        now.setToNow();
        String sTime = now.format("%Y_%m_%d_%H_%M_%S");
        return sTime;
    }

}

你可以使用SimpleDateFormat类:

SimpleDateFormat s = new SimpleDateFormat("ddMMyyyyhhmmss");
String format = s.format(new Date());

来自开发者博客:

System.currentTimeMillis() is the standard "wall" clock (time and date) expressing milliseconds since the epoch. The wall clock can be set by the user or the phone network (see setCurrentTimeMillis(long)), so the time may jump backwards or forwards unpredictably. This clock should only be used when correspondence with real-world dates and times is important, such as in a calendar or alarm clock application. Interval or elapsed time measurements should use a different clock. If you are using System.currentTimeMillis(), consider listening to the ACTION_TIME_TICK, ACTION_TIME_CHANGED and ACTION_TIMEZONE_CHANGED Intent broadcasts to find out when the time changes.

你可以通过尝试下面的代码在Android中获得当前时间戳

time.setText(String.valueOf(System.currentTimeMillis()));

和时间戳到时间格式

SimpleDateFormat formatter = new SimpleDateFormat("dd/MM/yyyy");
String dateString = formatter.format(new Date(Long.parseLong(time.getText().toString())));
time.setText(dateString);

这里是另一个解决方案，这是在kotlin:

val df: DateFormat = SimpleDateFormat("yyyy.MM.dd HH:mm:ss")
val timeStamp = df.format(Calendar.getInstance().time)

输出的例子:

"2022.04.22 10:22:35"

我建议使用Hits的答案，但添加一个Locale格式，这是如何Android 开发人员建议:

try {
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault());
        return dateFormat.format(new Date()); // Find todays date
    } catch (Exception e) {
        e.printStackTrace();

        return null;
    }