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对我来说，一些外部函数给了我一个 java.io.File 实例，但我想即时更改该实例的 compareTo 的默认行为。最好的方法是什么？

我唯一能想到的就是将这个 File 实例包装成一个

public class FileWrapper extends File{   

    FileWrapper(File in){
        //Assign var to the global var      
    }

    @Overrides
    public compareTo(File in){ return whatever;}

}

并让所有方法覆盖 File 的方法并将调用转发到通过构造函数传递的全局包装实例，但它非常难看......

也许我忘记了其他更简单的方法......

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1 回答 1

3

您可能要使用该compareTo方法的唯一原因是对集合进行排序。

您始终可以创建 aComparator并将其传递给Collections.sort调用。

Collections.sort(myList, new Comparator<File>() {
    public int compare(File file1, File file2) {
        // write your custom compare logic here.
    }
});

即使您使用诸如 的排序集合TreeSet，它也已经为您提供了一个重载的构造函数来传递Comparator.

/**
 * Constructs a new, empty tree set, sorted according to the specified
 * comparator.  All elements inserted into the set must be <i>mutually
 * comparable</i> by the specified comparator: {@code comparator.compare(e1,
 * e2)} must not throw a {@code ClassCastException} for any elements
 * {@code e1} and {@code e2} in the set.  If the user attempts to add
 * an element to the set that violates this constraint, the
 * {@code add} call will throw a {@code ClassCastException}.
 *
 * @param comparator the comparator that will be used to order this set.
 *        If {@code null}, the {@linkplain Comparable natural
 *        ordering} of the elements will be used.
 */
public TreeSet(Comparator<? super E> comparator) {
    this(new TreeMap<E,Object>(comparator));
}
于 2012-05-31T09:54:42.713 回答