Java OptionalDouble equals()用法及代碼示例

OptionalDouble幫助我們創建一個可能包含或可能不包含Double值的對象。 equals(Object obj)方法可幫助我們將此OptionalDouble對象與傳遞的對象作為參數進行比較，如果對象相等，則返回true。

如果滿足以下條件，則認為另一個對象與此OptionalDouble相等：

它也是一個OptionalDouble和;
兩個實例都不存在值；或者
當前值通過==彼此為“equal to”。

用法:

public boolean equals(Object obj)

參數：此方法接受obj，它是要測試是否相等的對象。

返回值：如果另一個對象是“equal to”，則此方法返回true；否則返回false。

以下示例程序旨在說明equals(Object obj)方法：

示例1:

// Java program to demonstrate 
// OptionalDouble.equals(Object obj) method 
  
import java.util.OptionalDouble; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Create first OptionalDouble object 
        OptionalDouble opDouble1 
            = OptionalDouble.of(452.13246); 
  
        System.out.println("OptionalDouble 1: "
                           + opDouble1.toString()); 
  
        // Create second OptionalDouble object 
        OptionalDouble opDouble2 
            = OptionalDouble.of(452.13246); 
  
        System.out.println("OptionalDouble 2: "
                           + opDouble2.toString()); 
  
        // Check if these two objects are equal 
        // using equals(Object obj) 
        System.out.println("Are both objects equal: "
                           + opDouble1.equals(opDouble2)); 
    } 
}

輸出：

OptionalDouble 1: OptionalDouble[452.13246]
OptionalDouble 2: OptionalDouble[452.13246]
Are both objects equal: true

示例2:

// Java program to demonstrate 
// OptionalDouble.equals(Object obj) method 
  
import java.util.OptionalDouble; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
        // Create first OptionalDouble object 
        OptionalDouble opDouble1 
            = OptionalDouble.of(3179464.92); 
  
        System.out.println("OptionalDouble 1: "
                           + opDouble1.toString()); 
  
        // Create second OptionalDouble object 
        OptionalDouble opDouble2 
            = OptionalDouble.of(4521.3246); 
  
        System.out.println("OptionalDouble 2: "
                           + opDouble2.toString()); 
  
        // Check if these two objects are equal 
        // using equals(Object obj) 
        System.out.println("Are both objects equal: "
                           + opDouble1.equals(opDouble2)); 
    } 
}

輸出：

OptionalDouble 1: OptionalDouble[3179464.92]
OptionalDouble 2: OptionalDouble[4521.3246]
Are both objects equal: false

參考文獻： https://docs.oracle.com/javase/10/docs/api/java/util/OptionalDouble.html#equals?(Object obj)

相關用法

注：本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 OptionalDouble equals() method in Java with examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。