比较两个对象并检查 null [英] Compare two objects with a check for null

问题描述

JDK 中是否有一种方法可以比较两个对象的相等性，并考虑空值?像这样:

Is there a method in the JDK that compares two objects for equality, accounting for nulls? Something like this:

public static boolean equals(Object o1, Object o2)
{
    if (o1 == null)
    {
        return o2 == null; // Two nulls are considered equal
    }
    else if (o2 == null)
    {
        return false;
    }

    return o1.equals(o2);
}

自己编写这个方法似乎很愚蠢，因为我认为它必须已经存在于某处.

It seems silly to write this method myself since I would think that it has to exist already somewhere.

推荐答案

Java 7.0 添加了一个新的方便的类:Objects.

Java 7.0 added a new handy class: Objects.

它有一个专门用于此的方法:Objects.equals(Object a, Object b)

It has a method exactly for this: Objects.equals(Object a, Object b)

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