java比较器 之compareable 和comparato比较

compareable

测试类
import java.util.Set;
import java.util.TreeSet;

public class Test {

    public static void main(String[] args) {
        Set<Person>allset = new TreeSet<Person>();
        allset.add(new Person(22,"hjw",20000.0,"论语",50.0));
        allset.add(new Person(22,"fyy",7000.0,"大学",40.0));
        allset.add(new Person(22,"hjl",6000.0,"孟子",30.0));
        allset.add(new Person(22,"hlq",10000.0,"中庸",20.0));
        allset.add(new  Person(24, "hsx", 20000.0,"诗经", 40.0));
        allset.add(new Person(22,"cl",20000.0,"离骚",10.0));
        allset.add(new Person(22,"zsk",20000.0,"墨子",25.0));
        allset.add(new Person(22,"hjw",20000.0,"论语",23.0));
        allset.add(new Person(22,"hjw",20000.0,"论语",22.0));
        System.out.println(allset);
    }

}

person类
public class Person extends Book implements Comparable<Person> {
    private Integer age;
    private String name;
    private Double salary;
    //private String book;
    public Integer getAge() {
        return age;
    }
    public Person(Integer age, String name, Double salary,String bookname, double price) {
        super(bookname, price);
        this.age = age;
        this.name = name;
        this.salary = salary;
        //this.book = book;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Double getSalary() {
        return salary;
    }
    public void setSalary(double salary) {
        this.salary = salary;
    }
    @Override
    public int compareTo(Person o) {

        if (this.salary>o.salary) {
            return -1;
        }
        else if(this.salary<o.salary){
            return 1;
        }
        else 
        {
            if (this.age>o.age){
                return 1;
            }else if(this.age<o.age){
                return -1;
            }else{
                if (this.name!=o.name) {
                    return this.name.compareTo(o.name);
                }else {
                    if(this.price>o.price){
                        return 1;
                    }else if(this.price<o.price){
                        return -1;
                    }else {
                        return this.bookname.compareTo(o.bookname);
                    }
                }
            }
        }
    }
    @Override
    public String toString() {
        return "Person [age=" + age + ", name=" + name + ", salary=" + salary + ", bookname=" + bookname + ", price="
                + price + "]";
    }

}

Book类
public class Book {
    public String bookname;
    public Double price;
    
    public Book(String bookname, double price) {
        
        this.bookname = bookname;
        this.price = price;
    }
    public String getBookname() {
        return bookname;
    }
    public void setBookname(String bookname) {
        this.bookname = bookname;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    @Override
    public String toString() {
        return "Book [bookname=" + bookname + ", price=" + price + "]";
    }
    
    
}

自定义比较器Comparator类

Book类
public class Book {
    public String bookname;
    public Double price;
    public Book(){}
    public Book(String bookname, double price) {
        
        this.bookname = bookname;
        this.price = price;
    }
    public String getBookname() {
        return bookname;
    }
    public void setBookname(String bookname) {
        this.bookname = bookname;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    @Override
    public String toString() {
        return "Book [bookname=" + bookname + ", price=" + price + "]";
    }
    
    
}

Person类
public class Person {
    private Integer age;
    private String name;
    private double salary;
    private Book book;
    public Person(Integer age, String name, double salary,String bookname, double price) {
        
        this.age = age;
        this.name = name;
        this.salary = salary;
        this.book=new Book(bookname,price);

    }
    public Integer getAge() {return age;}
    public void setAge(Integer age) {
        this.age = age;
    }
    public Book getBook() {
        return book;
    }
    public void setBook(Book book) {
        this.book = book;
    }
    public void setSalary(double salary) {
        this.salary = salary;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public double getSalary() {
        return salary;
    }
    
    @Override
    public String toString() {
        return "Person [age=" + age + ", name=" + name + ", salary=" + salary + ", book=" + book + "]";
    }
    
    
}

自定义Comparator类
import java.util.Comparator;

public class SalaryCom implements Comparator<Person>{

    @Override
    public int  compare(Person o1, Person o2) {
        if(o1.getSalary()!=o2.getSalary()){
        return (int) -(o1.getSalary()-o2.getSalary());
        }else if(o1.getAge()!=o2.getAge()){
            return (int) (o1.getAge()-o2.getAge());
        }else if(o1.getName()!=o2.getName()){
            return o1.getName().compareTo(o2.getName());}
            else{
                if(o1.getBook().price!=o2.getBook().price){
                    return (int) (o1.getBook().price-o2.getBook().price);
                }else{
                    return o1.getBook().bookname.compareTo(o2.getBook().bookname);
                }
                    
            }
        }
    }

Test类
import java.util.Set;
import java.util.TreeSet;
public class Test {

    public static void main(String[] args) {
        SalaryCom s =new SalaryCom();
        Set<Person> allset = new TreeSet<Person>(s);
        
        allset.add(new Person(22,"hjw",20000,"论语",50.0));
        allset.add(new Person(22,"fyy",7000,"大学",40.0));
        allset.add(new Person(22,"hjl",6000,"孟子",30.0));
        allset.add(new Person(22,"hlq",10000,"中庸",20.0));
        allset.add(new  Person(24,"hsx",20000,"诗经", 40.0));
        allset.add(new Person(22,"cl",20000,"离骚",10.0));
        allset.add(new Person(22,"zsk",20000,"墨子",25.0));
        allset.add(new Person(22,"hj",20000,"论语",50.0));
        allset.add(new Person(22,"hjw",20000,"论语",22.0));
        System.out.println(allset);
    }

}

使用匿名内部类自定义比较器Comparator

Book类

public class Book {
    public String bookname;
    public Double price;
    public Book(){}
    public Book(String bookname, double price) {
        
        this.bookname = bookname;
        this.price = price;
    }
    public String getBookname() {
        return bookname;
    }
    public void setBookname(String bookname) {
        this.bookname = bookname;
    }
    public double getPrice() {
        return price;
    }
    public void setPrice(double price) {
        this.price = price;
    }
    @Override
    public String toString() {
        return "Book [bookname=" + bookname + ", price=" + price + "]";
    }
    
    
}

Person类
public class Person {
    private Integer age;
    private String name;
    private double salary;
    private Book book;
    public Person(Integer age, String name, double salary,String bookname, double price) {
        
        this.age = age;
        this.name = name;
        this.salary = salary;
        this.book=new Book(bookname,price);

    }
    public Integer getAge() {return age;}
    public void setAge(Integer age) {
        this.age = age;
    }
    public Book getBook() {
        return book;
    }
    public void setBook(Book book) {
        this.book = book;
    }
    public void setSalary(double salary) {
        this.salary = salary;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public double getSalary() {
        return salary;
    }
    
    @Override
    public String toString() {
        return "Person [age=" + age + ", name=" + name + ", salary=" + salary + ", book=" + book + "]";
    }
    
    
}

Test测试类
import java.util.Comparator;
import java.util.Set;
import java.util.TreeSet;

import com.qianfeng.homework02.Person;

public class Test {

    public static void main(String[] args) {
    Set<Person> allset = new TreeSet<Person>(new Comparator<Person>() {

        @Override
        public int compare(Person o1, Person o2) {
            if(o1.getSalary()!=o2.getSalary()){
                return (int) -(o1.getSalary()-o2.getSalary());
                }else if(o1.getAge()!=o2.getAge()){
                    return (int) (o1.getAge()-o2.getAge());
                }else if(o1.getName()!=o2.getName()){
                    return o1.getName().compareTo(o2.getName());}
                    else{
                        if(o1.getBook().price!=o2.getBook().price){
                            return (int) (o1.getBook().price-o2.getBook().price);
                        }else{
                            return o1.getBook().bookname.compareTo(o2.getBook().bookname);
                        }
                            
                    }
        }
    });
        
        allset.add(new Person(22,"hjw",20000,"论语",50.0));
        allset.add(new Person(22,"fyy",7000,"大学",40.0));
        allset.add(new Person(22,"hjl",6000,"孟子",30.0));
        allset.add(new Person(22,"hlq",10000,"中庸",20.0));
        allset.add(new  Person(24,"hsx",20000,"诗经", 40.0));
        allset.add(new Person(22,"cl",20000,"离骚",10.0));
        allset.add(new Person(22,"zsk",20000,"墨子",25.0));
        allset.add(new Person(22,"hj",20000,"论语",50.0));
        allset.add(new Person(22,"hjw",20000,"论语",22.0));
        System.out.println(allset.size());
        System.out.println(allset);

    }

}

注意：String 字符串类的Comparator已经实现了compareTo方法，可以直接进行调用比较！