Java Calendar before() 方法

2024 年 11 月 3 日 | 阅读 3 分钟

java.util.Calendar.before() 是 java.util 包中 Calendar 类的一个方法。该方法在返回的 Calendar 对象所表示的时间早于 when 对象所表示的时间时返回 true。如果不是这种情况，则返回 false。

语法

参数

when - 要进行比较的 Object。

返回值

此方法返回 True 或 False 值

抛出

不适用

示例 1

import java.util.Calendar;
import java.util.Date;
public class CalendarbeforeExample1 {
    	 public static void main(String[] args) {
   // create calendar objects.
       Calendar cal = (Calendar) Calendar.getInstance();
      Calendar past = (Calendar) Calendar.getInstance();
      // print the current date
      System.out.println("Current date: " + cal.getTime());
      // change year in future calendar
      past.set(Calendar.YEAR, 2015);
      System.out.println("Year is " + past.get(Calendar.YEAR));
      // check if calendar date is after current date
      Date time = past.getTime();
           if (past.before(cal)) {
         System.out.println("Date " + time + " is before current date.");
      }
   }
}

输出

Current date: Mon Jul 30 04:08:30 PDT 2018
Year is 2015
Date Thu Jul 30 04:08:30 PDT 2015 is before current date.

示例 2

import java.util.Calendar;
import java.util.Date;
public class CalendarbeforeExample2 {   
public static void main(String[] args) {  
     // create calendar objects.
       Calendar cal = (Calendar) Calendar.getInstance();
     Calendar cal2 = (Calendar) Calendar.getInstance();
      // print the current date
      System.out.println("Current date: " + cal.getTime());
      // change year in future calendar
      cal2.set(Calendar.MONTH, 4);
      System.out.println("Year is " + cal2.get(Calendar.MONTH));
      // check if calendar date is after current date
      Date time = cal2.getTime();     
      if (cal2.before(cal)) {
         System.out.println("Date " + time + " is before current date.");
      }
   }
}

输出

Current date: Mon Jul 30 04:13:04 PDT 2018
Year is 4
Date Wed May 30 04:13:04 PDT 2018 is before current date.

示例 3

import java.util.Calendar;
import java.util.Date;
public class CalendarbeforeExample3 {
public static void main(String[] args) {
      // create calendar objects.
       Calendar cal = (Calendar) Calendar.getInstance();
      Calendar cal3 = (Calendar) Calendar.getInstance();
      // print the current date
      System.out.println("Current date: " + cal.getTime());
      // change year in future calendar
      cal3.set(Calendar.DAY_OF_MONTH, 23);
      System.out.println("Year is " + cal3.get(Calendar.DAY_OF_MONTH));
      // check if calendar date is after current date
      Date time = cal3.getTime();
      if (cal3.before(cal)) {
         System.out.println("Date " + time + " is before current date.");
      }   
  }   
 }

输出

Current date: Mon Jul 30 06:19:04 PDT 2018
Year is 23
Date Mon Jul 23 06:19:04 PDT 2018 is before current date.

示例 4

import java.util.Calendar;
import java.util.Date;
public class CalendarbeforeExample4 {    
public static void main(String[] args) {   
      // create calendar objects.
       Calendar cal = (Calendar) Calendar.getInstance();
      Calendar cal3 = (Calendar) Calendar.getInstance();
      // print the current date
      System.out.println("Current date: " + cal.getTime());
      // change year in future calendar
      cal3.set(Calendar.HOUR, 30);
      System.out.println("Now date is  " + cal3.getTime());
       cal3.set(Calendar.MINUTE, 60);
      System.out.println("Now date is  " + cal3.getTime());  
       cal3.set(Calendar.SECOND, 30);
      System.out.println("Now date is  " + cal3.getTime());    
      // check if calendar date is after current date
      Date time = cal3.getTime();     
      if (cal3.before(cal)) {
         System.out.println("Date " + time + " is after current date.");
      }
}
}

输出

Current date: Mon Jul 30 06:23:37 PDT 2018
Now date is  Tue Jul 31 06:23:37 PDT 2018
Now date is  Tue Jul 31 07:00:37 PDT 2018
Now date is  Tue Jul 31 07:00:30 PDT 2018

下一主题Java-calendar-clear-method

Java Calendar before() 方法

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Java Calendar before() 方法

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示例 1

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示例 3

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