如何获取实例编号

Question

Is there way how to get instance number or id, I mean that what you can see in eclipse Debug>Variables window after class name in value column.

Thanks

Answer 1

See System.identityHashCode which returns the number that would be returned if Object.hashCode had not been overridden on an object. It is not a perfect proxy for identity since multiple objects might have the same identity hash code, but it is pretty useful for debugging.

Answer 2

By default, debugger shows you the result of toString() method with the hashCode of the object. So, you can see the value by executing hashCode() method.

Answer 3

我想你是在引用Objects toString（）实现：

return getClass().getName() + "@" + Integer.toHexString(hashCode());

Answer 4

Maybe I'm wrong, but I don't think instances of a class are numbered. I have searched many times for a way to get instances of a particular class and according to my searches, it would be impossible. Instances have an address, but I see no use for a class instance number (objects are not sorted by class in memory AFAIK). Note that you can always create a mechanism for giving numbers to you instances of a particular class. Have a static count in the class and give its value to each new instance you create (in the constructor) and increment it each time. That would be a way to differentiate instances.