java - 按字母顺序对数组列表进行排序

Question

您好，我想知道如何对这个arrayList进行排序

public class Librarian {
    public static void main(String[] args){

        Library library = new Library();



        library.addBook(new FictionBook("The walk through the exam", "Andreas", 0));
        library.addBook(new FictionBook("The incredible Programmer", "John", 1));
        library.addBook(new FictionBook("The Calculator", "Pius", 1));
        library.addBook(new FictionBook("The gozzilla", "Henry", 1));
        library.addBook(new FictionBook("The game", "Pele", 0));
        library.addBook(new FictionBook("Racing on the moon", "Marco",0));
        library.addBook(new FictionBook("London Show", "William", 0));
        library.addBook(new FictionBook("Water fights", "Claudia", 1));
        library.addBook(new FictionBook("Monster and Dragons", "Woozer", 1));
        library.addBook(new FictionBook("Pencils and pins", "Xian", 0));

        for(FictionBook myFictionBook : library.library){
            System.out.println(myFictionBook.getAuthor());
        }
    }

Answer 1

正如其他人提到的，您可以在 java 类中实现可比较接口(interface)。更好的选择是使用外部 Comparator .

Comparator<FictionBook> comparator = new Comparator<FictionBook>() {

    public int compare(FictionBook a, FictionBook b) {
       return a.title.compareTo(b.title);
    }

}

如果您现在想根据发行年份对书籍进行排序，那么您只需实现另一个比较器并使用新的比较器即可。或者您编写一个 DecoratorComparator 来反转内部结果的结果。

逆向排序器:

Comparator<FictionBook> inverse = new Comparator<FictionBook>() {

    public int compare(FictionBook a, FictionBook b) {
       return comparator.compare(a, b) * -1;
    }

}

实际的排序也是通过 Collections.sort(list, comparator) 完成的。如果您想要灵活的排序解决方案，请使用比较器。