你也可以使用substring()

String date_s = "2011-01-18 00:00:00.0";
date_s.substring(0,10);

如果你想在日期前留出空格，那就用吧

String date_s = " 2011-01-18 00:00:00.0";
date_s.substring(1,11);

/**
 * Method will take Date in "MMMM, dd yyyy HH:mm:s" format and return time difference like added: 3 min ago
 *
 * @param date : date in "MMMM, dd yyyy HH:mm:s" format
 * @return : time difference
 */
private String getDurationTimeStamp(String date) {
    String timeDifference = "";

    //date formatter as per the coder need
    SimpleDateFormat sdf = new SimpleDateFormat("MMMM, dd yyyy HH:mm:s");
    TimeZone timeZone = TimeZone.getTimeZone("EST");
    sdf.setTimeZone(timeZone);
    Date startDate = null;
    try {
        startDate = sdf.parse(date);
    } catch (ParseException e) {
        MyLog.printStack(e);
    }

    //end date will be the current system time to calculate the lapse time difference
    Date endDate = new Date();

    //get the time difference in milliseconds
    long duration = endDate.getTime() - startDate.getTime();

    long diffInSeconds = TimeUnit.MILLISECONDS.toSeconds(duration);
    long diffInMinutes = TimeUnit.MILLISECONDS.toMinutes(duration);
    long diffInHours = TimeUnit.MILLISECONDS.toHours(duration);
    long diffInDays = TimeUnit.MILLISECONDS.toDays(duration);

    if (diffInDays >= 365) {
        int year = (int) (diffInDays / 365);
        timeDifference = year + mContext.getString(R.string.year_ago);
    } else if (diffInDays >= 30) {
        int month = (int) (diffInDays / 30);
        timeDifference = month + mContext.getString(R.string.month_ago);
    }
    //if days are not enough to create year then get the days
    else if (diffInDays >= 1) {
        timeDifference = diffInDays + mContext.getString(R.string.day_ago);
    }
    //if days value<1 then get the hours
    else if (diffInHours >= 1) {
        timeDifference = diffInHours + mContext.getString(R.string.hour_ago);
    }
    //if hours value<1 then get the minutes
    else if (diffInMinutes >= 1) {
        timeDifference = diffInMinutes + mContext.getString(R.string.min_ago);
    }
    //if minutes value<1 then get the seconds
    else if (diffInSeconds >= 1) {
        timeDifference = diffInSeconds + mContext.getString(R.string.sec_ago);
    } else if (timeDifference.isEmpty()) {
        timeDifference = mContext.getString(R.string.now);
    }

    return mContext.getString(R.string.added) + " " + timeDifference;
}

我们可以将今天的日期转换为“2020年6月12日”的格式。

String.valueOf(DateFormat.getDateInstance().format(new Date())));

请参阅此处“日期及时间模式”。http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html

import java.text.SimpleDateFormat;
import java.util.Date;
import java.text.ParseException;

public class DateConversionExample{

  public static void main(String arg[]){

    try{

    SimpleDateFormat sourceDateFormat = new SimpleDateFormat("yyyy-MM-DD HH:mm:ss");

    Date date = sourceDateFormat.parse("2011-01-18 00:00:00.0");


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

    }catch(ParseException e){
        e.printStackTrace();
    }
  } 

}

您可以尝试Java 8的新日期，更多信息可以在Oracle文档中找到。

或者你可以试试旧的

public static Date getDateFromString(String format, String dateStr) {

    DateFormat formatter = new SimpleDateFormat(format);
    Date date = null;
    try {
        date = (Date) formatter.parse(dateStr);
    } catch (ParseException e) {
        e.printStackTrace();
    }

    return date;
}

public static String getDate(Date date, String dateFormat) {
    DateFormat formatter = new SimpleDateFormat(dateFormat);
    return formatter.format(date);
}

   String str = "2000-12-12";
   Date dt = null;
   SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");

    try 
    {
         dt = formatter.parse(str);
    }
    catch (Exception e)
    {
    }

    JOptionPane.showMessageDialog(null, formatter.format(dt));