Java中的日历 add() 方法及示例

内部的 Calendar 类的add() 方法用于根据日历的规则从给定的日历字段（int field）中添加或减去特定的时间量（int amt）。

句法：

public abstract void add(int field, int amt)

参数：该方法有两个参数：

• 要执行操作的日历字段。 （整数型）
• 需要减去的时间量。 （整数型）

返回值：该方法不返回任何值。

示例 1：

Java

// Java Program to Illustrate add() Method
// of Calendar class
 
// Importing required classes
import java.util.Calendar;
 
// Main class
public class CalendarClassDemo {
 
    // Main driver method
    public static void main(String args[])
    {
        // Creating a Calendar class object
        Calendar calndr = Calendar.getInstance();
 
        // Displaying the current date
        // using getTime() method
        System.out.println("Current Date: "
                           + calndr.getTime());
 
        // Adding 50 days to the
        // Current Calendar
        // using add() method
        calndr.add(Calendar.DATE, 50);
 
        // Displaying the date now using getTime() method
        System.out.println("After 50 days: "
                           + calndr.getTime());
 
        // Subtracting 6 months from
        // the Current calendar
        calndr.add(Calendar.MONTH, -6);
 
        // Displaying the date now using getTime() method
        System.out.println("6 months ago it was: "
                           + calndr.getTime());
 
        // Subtracting 2 year from
        // the Current calendar
        calndr.add(Calendar.YEAR, -2);
 
        // Displaying the date now using getTime() method
        System.out.println("2 years ago it was: "
                           + calndr.getTime());
    }
}

输出：

Current Date: Tue Feb 12 10:54:21 UTC 2019
After 50 days: Wed Apr 03 10:54:21 UTC 2019
6 months ago it was: Wed Oct 03 10:54:21 UTC 2018
2 years ago it was: Mon Oct 03 10:54:21 UTC 2016

示例 2：

Java

// Java Program to Illustrate add() Method
// of Calendar class
 
// Importing required classes
import java.util.Calendar;
 
// Main class
public class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
        // Creating a calendar object
        Calendar calndr = Calendar.getInstance();
 
        // Displaying the current date
        // using getTime() method
        System.out.println("Current Date: "
                           + calndr.getTime());
 
        // Adding 30 days to the current calendar
        // using add() method
        calndr.add(Calendar.DATE, 30);
 
        // Printing the corresponding date
        System.out.println("After 30 days: "
                           + calndr.getTime());
 
        // Subtracting 3 months from the current calendar
        calndr.add(Calendar.MONTH, -3);
 
        // Printing the corresponding date
        System.out.println("3 months ago it was: "
                           + calndr.getTime());
 
        // Subtracting 10 years from
        // the Current calendar
        calndr.add(Calendar.YEAR, -10);
 
        // Printing the corresponding date
        System.out.println("10 years ago it was: "
                           + calndr.getTime());
    }
}

输出：

Current Date: Tue Feb 12 10:54:24 UTC 2019
After 30 days: Thu Mar 14 10:54:24 UTC 2019
3 months ago it was: Fri Dec 14 10:54:24 UTC 2018
10 years ago it was: Sun Dec 14 10:54:24 UTC 2008