java - 使用 Date 获取昨天的日期

Question

以下函数产生今天的日期；我怎样才能让它只产生昨天的日期？

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

我只需要像下面这样的昨天的日期。是否可以在我的功能中执行此操作？

2012-07-09

Answer 1

更新

最近使用JSR-310对日期时间 API 进行了改进。

Instant now = Instant.now();
Instant yesterday = now.minus(1, ChronoUnit.DAYS);
System.out.println(now);
System.out.println(yesterday);

https://ideone.com/91M1eU

过时的答案

你减去了错误的数字：

改用Calendar：

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

• IDEOne 演示

Answer 2

您可以执行以下操作：

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

Note: if you want further backward date multiply number of day with 24*60*60*1000 for example:

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

Similarly, you can get future date by adding the value to System.currentTimeMillis(), for example:

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());
  }

Answer 6

没有直接的函数来获取昨天的日期。

要获得昨天的日期，您需要使用Calendarby 减去-1.

Answer 7

从您的代码更改：

private String toDate(long timestamp) {
    Date date = new Date (timestamp * 1000 -  24 * 60 * 60 * 1000);
   return new SimpleDateFormat("yyyy-MM-dd").format(date).toString();

}

但你最好使用calendar。

Answer 8

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()));