[英]Why doesn't Java autobox int to Integer for .equals(Object) method?
I was working on some java classes, and was overriding the .equals(Object)
method to test an integer variable of my class, and was surprised when it threw errors saying I could not use the primitive type int, when I was sure it said in the java docs that the compiler will automatically autobox primitive types into the wrapper types for methods. 我正在研究一些java类,并且正在重写
.equals(Object)
方法来测试我的类的整数变量,并且当它抛出错误说我无法使用原始类型int时,我很惊讶,当我确定它说在java docs中,编译器会自动将autobox基本类型转换为方法的包装类型。
public boolean equals(Object o)
{
if (!(o instanceof myClass))
return false;
myClass mc = (myClass)o;
return (this.myInt.equals(mc.getMyInt()));
}
I suppose that "this.myInt" is a int and not a Integer. 我想“this.myInt”是一个int而不是一个Integer。 Autoboxing would work in the parameter.
自动装箱可以在参数中使用。 Here are some exemple
这是一些例子
int a = 1;
int b = 1;
Integer c = 1;
Integer d = 1;
a.equals(b); // doesnt work as equals isn't define on int
c.equals(b); // work, c is an Integer/Object and b is autoboxed
c.equals(d); // work, both are Integer/Object
You could just use return (this.myInt==mc.getMyInt());
你可以使用
return (this.myInt==mc.getMyInt());
. 。 the
equals()
method is only defined for Objects. equals()
方法仅为Objects定义。
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