为什么在Java中BigInteger.one不等于new BigInteger（“1”）？[副本]

Question

System.out.println(new BigInteger("1")==BigInteger.ONE);

Answer 1

==检查对象是否指向相同的引用，因此如果a=b，则条件a==b。建议只对基元类型执行此操作。

要检查对象的内容是否相同，请使用函数equals(Object otherObject)。例如：

new BigInteger("1").equals(BigInteger.ONE); 

这将返回true，因为这两个对象的内容是相同的。但是使用==将返回false，因为每个对象都有不同的引用。

MyObject object1 = new MyObject(30);
MyObject object2 = object1; //this will make them have the same reference

// This prints true, as they have the same content.
System.out.println(object1.equals(object2));

// This will print true, as they point the same thing, because they have the same reference
System.out.println(object1 == object2);

// We can see they have the same reference because if we edit one's field, 
// the other's one will change too.
object1.number = 10;
System.out.println(object1.number); // prints 10
System.out.println(object2.number); // prints 10 too