Java LocalDate类| minus（）方法与示例

LocalDate类isSupported()方法 (LocalDate Class isSupported() method)

Syntax:

句法：

public LocalDate minus(TemporalAmount t_amt);
public LocalDate minus(long amt, TemporalUnit t_unit);

isSupported() method is available in java.time package.
isSupported()方法在java.time包中可用。
minus(TemporalAmount t_amt) method is used to subtract the given amount from this LocalDate and return the LocalDate.
minus(TemporalAmount t_amt)方法用于从此LocalDate中减去给定的金额并返回LocalDate。
minus(long amt, TemporalUnit t_unit) method is used to subtract the given amount in the given unit from this LocalDate and return the LocalDate.
minus(long amt，TemporalUnit t_unit)方法用于从此LocalDate中减去给定单位的给定数量，并返回LocalDate。
These methods may throw an exception at the time of performing subtraction.
这些方法在执行减法时可能会引发异常。
- ArithmeticException: This exception may throw when the calculated result exceeds the limit to represent this object.ArithmeticException ：当计算结果超出表示此对象的限制时，可能引发此异常。
- DateTimeException: This exception may throw when getting any error during subtraction.DateTimeException ：在减法过程中遇到任何错误时，都可能引发此异常。
- UnsupportedTemporalTypeException: This exception may throw when the given unit is unsupported.UnsupportedTemporalTypeException ：当不支持给定单元时，可能引发此异常。
These are non-static methods and it is accessible with class objects and if we try to access these methods with the class name then we will get an error.
这些是非静态方法，可通过类对象访问，如果尝试使用类名访问这些方法，则会收到错误消息。

Parameter(s):

参数：

In the first cases, minus(TemporalAmount t_amt),
在第一种情况下，减号(TemporalAmount t_amt)，
- TemporalAmount t_amt – represents the amount to be subtracted from this LocalDate.
- TemporalAmount t_amt –表示要从此LocalDate中减去的数量。
In the second cases, minus(long amt, TemporalUnit t_unit),
在第二种情况下，减号(long amt，TemporalUnit t_unit)，
- long amt – represents the amount in units to be subtracted from this LocalDate.
- long amt-表示要从此LocalDate中减去的金额(单位)。
- TemporalUnit t_unit – represents the unit to measure the given amount.
- TemporalUnit t_unit –代表测量给定数量的单位。

Return value:

返回值：

In both the cases, the return type of the method is LocalDate,

在这两种情况下，方法的返回类型均为LocalDate 。

In the first case, it returns the LocalDate that holds the value subtracted the given amount from this LocalDate.
在第一种情况下，它将返回LocalDate，该LocalDate保留从此LocalDate中减去给定值的值。
In the second case, it returns the LocalDate that holds the value subtracted the given amount in unit from this LocalDate.
在第二种情况下，它将返回LocalDate，该LocalDate保留从此LocalDate中减去以单位为单位的给定值的值。

Example:

例：

// Java program to demonstrate the example 
// of minus() method of LocalDate
import java.time.*;
import java.time.temporal.*;
public class MinusOfLocalDate {
public static void main(String args[]) {
long amt = 4;
// Instantiates two LocalDate
LocalDate l_da1 = LocalDate.parse("2007-04-04");
LocalDate l_da2 = LocalDate.now();
// Instantiates a Period 
Period weeks = Period.ofWeeks(2);
// Display l_da1,l_da2 and amt
System.out.println("LocalDate l_da1 and l_da2: ");
System.out.println("l_da1: " + l_da1);
System.out.println("l_da2: " + l_da2);
System.out.println("amt to subtract: " + amt);
System.out.println();
// Here, this method subtracts the given
// amount from this LocalDate l_da1 i.e.
// here we are subtracting 2 weeks from
// this date l_da1
LocalDate l_date = l_da1.minus(weeks);
// Display l_date
System.out.println("l_da1.minus(weeks): " + l_date);
// Here, this method subtracts the given
// amount in the given unit from 
// this LocalDate l_da2 i.e. here
// we are subtracting the given amt
// (4) in the given unit (in months) 
// from this date l_da2
l_date = l_da2.minus(amt, ChronoUnit.MONTHS);
// Display l_date
System.out.println("l_da2.minus(amt,ChronoUnit.MONTHS): " + l_date);
}
}

Output

输出量

LocalDate l_da1 and l_da2: 
l_da1: 2007-04-04
l_da2: 2020-06-03
amt to subtract: 4l_da1.minus(weeks): 2007-03-21
l_da2.minus(amt,ChronoUnit.MONTHS): 2020-02-03