You must override hashCode in every class that overrides equals.If you fail to do so, your class will violate(vt.违反) the general contract for hashCode, which will prevent it from functioning properly(adv.适当地,正确地) in collections such as HashMap and HashSet. Here is the contract, ad...
@OverridepublicinthashCode(){returnDouble.hashCode(value);}publicstaticinthashCode(doublevalue){longbits=doubleToLongBits(value);return(int)(bits^(bits>>>32));} 问题二: 回忆下文章开始的hashCode规范, 三条规则概括起来是两条内容: 一是hashCode返回要正确, 不会影响业务; 二是好的hashCode会系统提高性能....
1.You must override hashCode in every class that overrides equals. 如果一个类实现了equals方法却没有实现hashCode方法,那么将这个对象A放入HashMap中,然后new一个与A相等的对象B,在HashMap中查找B,返回值将是null,因为没有实现hashCode方法,导致相等的两个对象返回的hash值不同(因为A==B为false)。 2.JavaSE...
Failure to do so will result in a violation of the general contract for Object.hashCode, which will prevent your class from functioning properly in conjunction with all hash-based collections, including HashMap, HashSet, and Hashtable. Simple recipe for override hashCode 1. Store some constant n...
Java之所有对象的公用方法>9.Always override hashCode when you override equals You must override hashCode in every class that overrides equals.
using System; public struct S : IEquatable<S> { private readonly int _value; public S(int f) { _value = f; } public bool Equals(S other) => _value == other._value; public override bool Equals(object obj) => obj is S objS && Equals(objS); public override int GetHashCode() ...
using System; public struct S : IEquatable<S> { private readonly int _value; public S(int f) { _value = f; } public override int GetHashCode() => _value.GetHashCode(); public override bool Equals(object other) => other is S otherS && Equals(otherS); public bool Equals(S other)...
importjava.io.Serializable;importio.opensw.scheduler.core.scheduler.task.TaskData;importlombok.Data;importlombok.EqualsAndHashCode;importlombok.NoArgsConstructor;@Data@EqualsAndHashCode(callSuper=false)@NoArgsConstructorpublicclassEmailextendsTaskDataimplementsSerializable{privatestaticfinallongserialVersionUID= -24839...
Thanks for contributing. Tick to sign-off your agreement to the Developer Certificate of Origin (DCO) 1.1 Description Re-implemented Table.isDuplicate to be much simpler and probably faster Fixe...
Object是Java中所有类的父类,对它的学习十分的重要, Object的函数除了final方法,基本上都是被设计为要被覆盖的(Override),这节我们就一起来学习这些函数。 1.equals函数 /*equals的源代码*/ public boolean equals(Object obj) { return (this == obj); ...