4. java.util.Calendar( 日历)类 类
Calendar是一个抽象基类,主用用于完成日期字段之间相互操作的功能。
获取Calendar实例的方法
使用Calendar.getInstance()方法
调用它的子类GregorianCalendar的构造器。
一个Calendar的实例是系统时间的抽象表示,通过get(int field)方法来取得想
要的时间信息。比如YEAR、MONTH、DAY_OF_WEEK、HOUR_OF_DAY 、
MINUTE、SECOND
public void set(int field,int value)
public void add(int field,int amount)
public final Date getTime()
public final void setTime(Date date)
注意:
获取月份时:一月是0,二月是1,以此类推,12月是11
获取星期时:周日是1,周二是2 , 。。。。周六是7
/* Calendar日历类(抽象类)的使用 */ @Test public void testCalendar(){ //1.实例化 //方式一:创建其子类(GregorianCalendar)的对象 //方式二:调用其静态方法getInstance() Calendar calendar = Calendar.getInstance(); // System.out.println(calendar.getClass()); //2.常用方法 //get() int days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); System.out.println(calendar.get(Calendar.DAY_OF_YEAR)); //set() //calendar可变性 calendar.set(Calendar.DAY_OF_MONTH,22); days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); //add() calendar.add(Calendar.DAY_OF_MONTH,-3); days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); //getTime():日历类---> Date Date date = calendar.getTime(); System.out.println(date); //setTime():Date ---> 日历类 Date date1 = new Date(); calendar.setTime(date1); days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); } }
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esources.jar;C:Program FilesJavajdk1.8.0_131jrelib
t.jar;C:UsersAdministratorDesktopJavaSenioroutproductionday04;C:MyProgramInstallIntelliJ IDEA 2017.3.1plugins estnglib estng.jar;C:MyProgramInstallIntelliJ IDEA 2017.3.1plugins estnglibjcommander.jar;C:MyProgramInstallIntelliJ IDEA 2017.3.1libjunit-4.12.jar;C:MyProgramInstallIntelliJ IDEA 2017.3.1libhamcrest-core-1.3.jar" com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit4 com.atguigu.java.DateTimeTest,testCalendar
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