public String giveDate() {
    Calendar cal = Calendar.getInstance();
    SimpleDateFormat sdf = new SimpleDateFormat("EEE, MMM d, yyyy");
    return sdf.format(cal.getTime());
 }

Calendar cal = Calendar.getInstance();      
Calendar dt = Calendar.getInstance(); 
dt.clear();
dt.set(cal.get(Calendar.YEAR), cal.get(Calendar.MONTH),cal.get(Calendar.DATE)); 
return dt.getTime();        

试试这个,

SimpleDateFormat timeStampFormat = new SimpleDateFormat("yyyyMMddHHmmssSS");
Date myDate = new Date();
String filename = timeStampFormat.format(myDate);

在Kotlin

https://www.programiz.com/kotlin-programming/examples/current-date-time

fun main(args: Array<String>) {

val current = LocalDateTime.now()

val formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS")
val formatted = current.format(formatter)

println("Current Date and Time is: $formatted")}

如果你只想获取日期，就像这样输入代码

Calendar.getInstance().getTime();

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

//导入Date类为java.util