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📜  Java中的 OptionalDouble equals() 方法及示例

📅  最后修改于: 2022-05-13 01:54:51.956000             🧑  作者: Mango

Java中的 OptionalDouble equals() 方法及示例

OptionalDouble帮助我们创建一个可能包含也可能不包含 Double 值的对象。 equals(Object obj)方法帮助我们将此 OptionalDouble 对象与作为参数传递的对象进行比较,如果对象相等,则返回 true。

如果满足以下条件,则认为另一个对象等于此 OptionalDouble:

  • 它也是一个 OptionalDouble 并且;
  • 两个实例都没有价值,或者;
  • 当前值通过 == 彼此“相等”。

句法:

public boolean equals(Object obj)

参数:此方法接受一个obj ,它是要测试是否相等的对象。

返回值:如果另一个对象“等于”这个对象,则此方法返回 true,否则返回 false。

下面的程序说明了 equals(Object obj) 方法:

方案一:

// 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));
    }
}
输出:
OptionalDouble 1: OptionalDouble[452.13246]
OptionalDouble 2: OptionalDouble[452.13246]
Are both objects equal: true

方案二:

// 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));
    }
}
输出:
OptionalDouble 1: OptionalDouble[3179464.92]
OptionalDouble 2: OptionalDouble[4521.3246]
Are both objects equal: false

参考资料: https: Java/util/OptionalDouble.html#equals?(Object obj)