Java-Point类的hashCode()方法有什么好处，还是应该重写它并编写自己的方法? [英] Java - Is the Point class's hashCode() method any good, or should I override it and write my own?

问题描述

有什么办法可以实际看到标准Java类的源代码吗?我正在制作一个散列点(HashSet<Point>)，我想确保它能很好地散列，但是我看不到Point的hashCode()方法的实际外观，所以我不知道它的效果如何确实是.谁能帮我?我应该覆盖它吗?如果是这样，是否有一种简单的方法就可以执行此操作，而无需创建一个全新的Java文件/类?

Is there any way to actually see the source code of standard java classes by the way? I'm making a hash table of points (HashSet<Point>) and I want to make sure that it will hash well, but I can't see what Point's hashCode() method actually looks like, so I don't know how good it really is. Can anyone help me? Should I override it? And if so, is there an easy way to do this without creating a whole new java file/class?

推荐答案

如果要搜索java.awt.Point的hashCode()，则在java.awt.geom.Point2D中定义.

If you're searching for the hashCode() of java.awt.Point, it is defined in java.awt.geom.Point2D.

/**
 * Returns the hashcode for this <code>Point2D</code>.
 * @return      a hash code for this <code>Point2D</code>.
 */
public int hashCode() {
    long bits = java.lang.Double.doubleToLongBits(getX());
    bits ^= java.lang.Double.doubleToLongBits(getY()) * 31;
    return (((int) bits) ^ ((int) (bits >> 32)));
}

请注意，问题它能很好地哈希吗?" 很难回答，这主要取决于使用模式.

Note that the question "Will it hash well?" is hard to answer, it depends primarily on usage pattern.

您可以访问几乎所有标准Java类" 的源代码，只需在JDK安装目录中搜索src.zip文件(或使用Eclipse/NetBeans之类的IDE，然后单击F3在班级名称上).

You can access the source code of nearly all "standard Java classes", just search for the src.zip file in your JDK installation directory (or use an IDE like Eclipse/NetBeans and click F3 on the class name).

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