TreeSet中自定义排序的两种方法

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* 以此为例子*
人类，属性姓名，收入，年龄，书，
书类：属性书名，价格
存储TreeSet集合，排序规则：
A：先按照收入排序：从高到低
B：收入相等的情况下，按照年龄排序：从小到大
C：如果收入和年龄都相等，按照姓名排序，字典顺序（String类的compareTo方法）
D：如果以上3个属性都相等，按照书排序，先按照书价格：从低到高，如果书价格相等，按照书名（字典顺序）

方法1
//这里我是用的在题目的类中直接继承Comparable 重写了Comparable，TreeSet使用时直接比较了

public class Demo01 {    public static void main(String[] args) {        Book book=new Book("java", 20);        Book book2=new Book("Android", 22);        Person person=new Person("lcs", 2000, 20, book);        Person person2=new Person("lcs", 2000, 20, book2);        Set<Person> set=new TreeSet<>();        set.add(person);        set.add(person2);        System.out.println(set);    }}class Book implements Comparable<Book>{    private String bookname;    private int price;    public Book(String bookname, int price) {        super();        this.bookname = bookname;        this.price = 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 + "]";    }    //按照书排序，先按照书价格：从低到高，如果书价格相等，按照书名（字典顺序）    @Override    public int compareTo(Book o) {        if(this.getPrice()==o.getPrice()){            return this.getBookname().compareTo(o.getBookname());        }else if(this.getPrice()<o.getPrice()){            return -1;        }else             return 1;    }}class Person implements Comparable<Person>{    //人类，属性姓名，收入，年龄，书    private String name;    private int shouru;    private int age;    private Book book;    public Person(String name, int shouru, int age, Book book) {        super();        this.name = name;        this.shouru = shouru;        this.age = age;        this.book = book;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getShouru() {        return shouru;    }    public void setShouru(int shouru) {        this.shouru = shouru;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public Book getBook() {        return book;    }    public void setBook(Book book) {        this.book = book;    }    @Override    public String toString() {        return "Person [name=" + name + ", shouru=" + shouru + ", age=" + age                + ", book=" + book + "]";    }    /*     * A：先按照收入排序：从高到低              B：收入相等的情况下，按照年龄排序：从小到大        C：如果收入和年龄都相等，按照姓名排序，字典顺序（String类的compareTo方法）        D：如果以上3个属性都相等，按照书排序，先按照书价格：从低到高，如果书价格相等，按照书名（字典顺序）(non-Javadoc)     * @see java.lang.Comparable#compareTo(java.lang.Object)     */    @Override    public int compareTo(Person o) {        if(this.getShouru()==o.getShouru()){            if(this.getAge()==o.getAge()){                int a=this.getName().compareTo(o.getName());                if(a==0){                    return this.book.compareTo(o.book);                }else if(a<0){                    return -1;                }else                     return 1;            }else if(this.getAge()<o.getAge()){                return -1;            }else                return 1;        }else if(this.getShouru()<o.getShouru()){            return 1;        }else             return -1;    }}

方法2，具体的排序代码和方法1一样，没有具体写出
//这里使用的是定义了一个新的类，实现了comparator的接口，重写了比较的方法,重写关于Person的排序。
//Book的排序已经在Book类中通过实现Comparable接口写好了
//在main方法中这样调用：Set set=new TreeSet<>(new Mycompare());

public class Demo02 {    public static void main(String[] args) {        Set<Person> set=new TreeSet<>(new Mycompare());    }}class Book implements Comparable<Book>{    private String bookname;    private int price;    public Book(String bookname, int price) {        super();        this.bookname = bookname;        this.price = 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 + "]";    }    //按照书排序，先按照书价格：从低到高，如果书价格相等，按照书名（字典顺序）      @Override    public int compareTo(Book o) {        if(this.getPrice()==o.getPrice()){            return this.getBookname().compareTo(o.getBookname());        }else if(this.getPrice()<o.getPrice()){            return -1;        }else             return 1;    }}class Person{    //人类，属性姓名，收入，年龄，书    private String name;    private int shouru;    private int age;    private Book book;    public Person(String name, int shouru, int age, Book book) {        super();        this.name = name;        this.shouru = shouru;        this.age = age;        this.book = book;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getShouru() {        return shouru;    }    public void setShouru(int shouru) {        this.shouru = shouru;    }    public int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public Book getBook() {        return book;    }    public void setBook(Book book) {        this.book = book;    }    @Override    public String toString() {        return "Person [name=" + name + ", shouru=" + shouru + ", age=" + age                + ", book=" + book + "]";    }    /*     * A：先按照收入排序：从高到低              B：收入相等的情况下，按照年龄排序：从小到大        C：如果收入和年龄都相等，按照姓名排序，字典顺序（String类的compareTo方法）        D：如果以上3个属性都相等，按照书排序，先按照书价格：从低到高，如果书价格相等，按照书名（字典顺序）(non-Javadoc)     * @see java.lang.Comparable#compareTo(java.lang.Object)     */ }class Mycompare implements Comparator<Person>{    @Override    public int compare(Person o1, Person o2) {        // TODO Auto-generated method stub        return 0;    }}

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