java - 如何先按字母顺序排序ArrayList，然后按数字排序

Question

这是排序前的样子。书名、出版年份

我想按字母顺序对标题进行排序，然后按发布年份进行排序。
这是我当前在排序之前的编码:

    ArrayList BookList = new ArrayList();
    BufferedReader br = new BufferedReader (new FileReader ("bookInput.txt"));

    String str = br.readLine();
    while (str!=null){
        StringTokenizer st = new StringTokenizer(str,";");
        String title = st.nextToken();
        String yr = st.nextToken();
        int year = Integer.parseInt(yr);
        Book b1 = new Book (title,year);
        BookList.add(b1);
        str = br.readLine();
    }
    br.close();

    //3(d)
    System.out.println("List of Books" + "( " + BookList.size() + " record(s) ) ");
    for (int i = 0; i < BookList.size(); i++){
        Book b2 = (Book)BookList.get(i);
        System.out.println("#" + (i+1) + " " + b2.getTitle() + " , " + b2.getYear());
    }

我已经尝试了我所知道的一切，但失败了😅

Answer 1

您可以使用Comparator假设 Book 类具有 getters 的链:

BookList.sort(Comparator.comparing(Book::getTitle)
                        .thenComparingInt(Book::getYear));