????1??????????дequals()

???????????????????е?“??????”?????????????????????

????2???????дequals()????????????дhashCode()

???????????

????hashCode()????????equals()???????￡?

???????x.equals(y)????“true”?????x??y??hashCode()????????

???????x.equals(y)????“false”?????x??y??hashCode()?п?????????п???????

???????????“??????????????????????”??

????3??????equals()????????equals()

?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????object?????????????????

???????????????????????equals()??????????

?????ο???effective java????equals??????????

?????????????x.equals(y)??????“true”?????y.equals(x)???÷?????“true”??

???????????x.equals(x)????????“true”??

??????????????x.equals(y)??????“true”??????y.equals(z)??????“true”?????z.equals(x)???÷?????“true”??

?????????????????x.equals(y)??????“true”????x??y???????????????????x.equals(y)????Σ????????“true”??

?????κ?????￡?x.equals(null)???????????“false”??x.equals(??x???????????)?????????“false”??

?????????裺

????[1]???instanceof?????????“????????????????”??

????[2]???????е?????“?????”?????????е???????????ж?????????

????[2.1]?????float??double?????????????????==????

????[2.2]???????????????????equals??????

????[2.3]????float?????Float.floatToIntBits(afloat)????int???????==????

????[2.4]????double?????Double.doubleToLongBits(adouble) ????int???????==????

????[2.5]??????????????Arrays.equals??????

????4??????hashcode()????????hashCode()

????????????????????????????й?????????????????????????????????????????????????????ū????????????????????????????????в????? ???λ???????hashCode()????????????????????????Щ?????????????е?λ?á?

??????????HashMap??????????hashCode???????????????http://blog.csdn.net/a511596982/article/details/8138893

?????????裺

????[1]??????????????????17????????int????result?У?

????[2]??????????????????f???equals?????п????????????

????[2.1]boolean???????(f ? 0 : 1);

????[2.2]byte??char??short???????(int);

????[2.3]long???????(int) (f ^ (f>>>32));

????[2.4]float???????Float.floatToIntBits(afloat);

????[2.5]double???????Double.doubleToLongBits(adouble)??????long???????[2.3];

????[2.6]???????????????????hashCode????;

????[2.7]?????????????????????????hashCode??????

????[3]???????????????????浽int????c???????? result=37*result+c;