了解java中的过去30天,60天和90天

Question

如何获取java中给定日期的最后30/60/90天记录？

我有一些收到日期的记录.我想从收到的日期获取最近30或60或90天的记录.怎么解决？

Answer 1

使用java.util.Calendar.

Date today = new Date();
Calendar cal = new GregorianCalendar();
cal.setTime(today);
cal.add(Calendar.DAY_OF_MONTH, -30);
Date today30 = cal.getTime();
cal.add(Calendar.DAY_OF_MONTH, -60);
Date today60 = cal.getTime();
cal.add(Calendar.DAY_OF_MONTH, -90);
Date today90 = cal.getTime();

Answer 2

捆绑的java.util.Date和.Calendar类是众所周知的麻烦.避免他们.

乔达时间

下面是一些使用Joda-Time 2.3库的LocalDate类的示例代码.

LocalDate                       // Represent a date-only value, without time-of-day and without time zone.
.now(                           // Capture today's date as seen in the wall-clock time used by the people of a particular region (a time zone).
    ZoneId.of( "Asia/Tokyo" )   // Specify the desired/expected zone.
)                               // Returns a `LocalDate` object.
.minus(                         // Subtract a span-of-time.
    Period.ofDays( 30 )         // Represent a span-of-time unattached to the timeline in terms of years-months-days.
)                               // Returns another `LocalDate` object.

转储到控制台......

ZoneId z = ZoneId.of( "America/Montreal" ) ;  
LocalDate today = LocalDate.now( z ) ;

跑的时候......

ZoneId z = ZoneId.systemDefault() ;  // Get JVM’s current default time zone.

时区

一天的开始和结束取决于您的时区.巴黎新的一天早于蒙特利尔.

默认情况下,LocalDate类使用JVM的默认时区来确定当前日期.或者,您可以传递DateTimeZone对象.

LocalDate ld = LocalDate.of( 1986 , 2 , 23 ) ;  // Years use sane direct numbering (1986 means year 1986). Months use sane numbering, 1-12 for January-December.

java.time

Java 8带来了新的内置java.time包.这些新类旨在取代旧的捆绑java.util.Date/Calendar类.java.time类的灵感来自JSR 310定义的Joda-Time.

在本课题的特定情况下,上面看到的Joda-Time示例代码与java.time完全相同.只有LocalDate陈述会有所不同.