Java OptionalDouble equals()方法及示例

OptionalDouble 帮助我们创建一个对象，该对象可能包含或不包含一个Double值。 equals(Object obj) 方法帮助我们比较这个OptionalDouble对象和作为参数传递的对象，如果对象相等，则返回true。

另一个对象被认为是等于这个OptionalDouble，如果。

语法

public boolean equals(Object obj)

参数： 该方法接受一个 obj ，它是一个要进行平等测试的对象。

返回值： 如果其他对象 “等于 “该对象，该方法返回真，否则返回假。

下面的程序说明了equals(Object obj)方法。

程序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));    }}

输出。

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

程序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));    }}

输出。

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

**参考资料: ** https://docs.oracle.com/javase/10/docs/api/java/util/OptionalDouble.html#equals? (Object obj)