使用日期获取昨天的日期

Question

以下函数生成今天的日期; 我怎么能让它只生产昨天的日期？

private String toDate() {
        DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
        Date date = new Date();    
        return dateFormat.format(date).toString();
}

这是输出:

2012-07-10

我只需要昨天的日期,如下所示.可以在我的功能中执行此操作吗？

2012-07-09

Answer 1

你正在减去错误的数字:

Calendar改为使用:

private Date yesterday() {
    final Calendar cal = Calendar.getInstance();
    cal.add(Calendar.DATE, -1);
    return cal.getTime();
}

然后,将您的方法修改为以下内容:

private String getYesterdayDateString() {
        DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
        return dateFormat.format(yesterday());
}

看到

• IDEOne演示

Answer 2

你可以这样做:

private Date getMeYesterday(){
     return new Date(System.currentTimeMillis()-24*60*60*1000);
}

注意:如果您想要进一步的向后日期乘以24*60*60*1000的天数,例如:

private Date getPreviousWeekDate(){
     return new Date(System.currentTimeMillis()-7*24*60*60*1000);
}

同样,您可以通过将值添加到System.currentTimeMillis()来获取将来的日期,例如:

private Date getMeTomorrow(){
     return new Date(System.currentTimeMillis()+24*60*60*1000);
}

Answer 3

   Calendar cal = Calendar.getInstance();
   DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
   System.out.println("Today's date is "+dateFormat.format(cal.getTime()));

   cal.add(Calendar.DATE, -1);
   System.out.println("Yesterday's date was "+dateFormat.format(cal.getTime()));  

使用日历Api

Answer 4

试试这个:

private String toDate() {
    DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");

    // Create a calendar object with today date. Calendar is in java.util pakage.
    Calendar calendar = Calendar.getInstance();

    // Move calendar to yesterday
    calendar.add(Calendar.DATE, -1);

    // Get current date of calendar which point to the yesterday now
    Date yesterday = calendar.getTime();

    return dateFormat.format(yesterday).toString();
}

Answer 5

试试这个;

   public String toDate() {
       DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
       Calendar cal = Calendar.getInstance();
       cal.add(Calendar.DATE, -1);
       return dateFormat.format(cal.getTime());
  }