TreeSet集合排序方式二：定制排序Comparator

Comparator有两种实现方式：

1，匿名内部类

2，创建一个类用于实现Comparator，该类创建的对象就是比较器

Person类

public class Person implements Comparable<Person> {
    private String name;
    private String sex;
    private int age;
    private Book books;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public Book getBooks() {
        return books;
    }
    public void setBooks(Book books) {
        this.books = books;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", sex=" + sex + ", age=" + age +
                ", books.name=" + books.getBookName() + ", books.price=" + books.getPrice() + "]";
    }
    public Person(String name, String sex, int age, Book books) {
        super();
        this.name = name;
        this.sex = sex;
        this.age = age;
        this.books = books;
    }
    public Person() {
        super();
    }

}

Book类

package Homework3;

public class Book {
    //Book类中 有  书名,书的价格
    private String bookName;
    private int price;
    public String getBookName() {
        return bookName;
    }
    public void setBookName(String bookName) {
        this.bookName = bookName;
    }
    public int getPrice() {
        return price;
    }
    public void setPrice(int price) {
        this.price = price;
    }
    @Override
    public String toString() {
        return "Book [bookName=" + bookName + ", price=" + price + "]";
    }
    public Book(String bookName, int price) {
        super();
        this.bookName = bookName;
        this.price = price;
    }
    public Book() {
        super();
    }

}

Comparator实现–匿名内部类

public class Test {
    public static void main(String[] args){
        //Comparator
        TreeSet<Person> set2=new TreeSet<>(new Comparator<Person>() {

            @Override
            public int compare(Person o1, Person o2) {
                if(o1.getAge()>o2.getAge()){
                    return -1;
                }else if (o1.getAge()<o2.getAge()) {
                    return 1;
                }else {
                    CollationKey key=Collator.getInstance().getCollationKey(o1.getName());
                    CollationKey key2=Collator.getInstance().getCollationKey(o2.getName());
                    int n=key.compareTo(key2);
                    if(n>0){
                        return 1;
                    }else if (n<0) {
                        return -1;
                    }else {
                        int a=o1.getBooks().getPrice()-o2.getBooks().getPrice();
                        if(a>0){
                            return -1;
                        }else if (a<0) {
                            return 1;
                        }else {
                            CollationKey key3=Collator.getInstance().getCollationKey(o1.getBooks().getBookName());
                            CollationKey key4=Collator.getInstance().getCollationKey(o2.getBooks().getBookName());
                            int m=key3.compareTo(key4);
                            if(m>0){
                                return 1;
                            }else if (m<0) {
                                return -1;
                            }else {
                                return 0;
                            }
                        }

                    }
                }
            }
        });
//          第一条件: 年龄 降序
            set2.add(new Person("Jane1", "female", 20, new Book("z指环王", 30)));
            set2.add(new Person("Jane2", "female", 30, new Book("z指环王", 30)));
//            第二条件: 姓名升序
            set2.add(new Person("Ada3", "female", 30, new Book("z指环王", 30)));
//            第三条件: 书的价格   降序
            set2.add(new Person("Ada4", "female", 30, new Book("z指环王", 50)));
//            第四条件: 书名     升序
            set2.add(new Person("Ada5", "female", 30, new Book("m指环王", 50)));
            System.out.println(set2);
    }
}