比较器Comparable和Comparator的使用

电玩女神 2022-12-29 09:08 256阅读 0赞

## 比较器Comparable和Comparator的使用 ##

> Comparable：为内部比较器  
> Comparator：为外部比较器

## **Comparable的使用** ##

public class Test { 
        public static void main(String[] args) { 
            Car[] cars= { new Car("奥迪", 12),
                    new Car("奔驰",18),
                    new Car("qq",10)
            };
    
            Arrays.sort(cars);
            System.out.println(Arrays.toString(cars));
    
        }
    }
    class Car implements Comparable<Car> { 
        private String name;
        private double age;
    
        public Car(String name, double age) { 
            this.name = name;
            this.age = age;
        }
        @Override
        public int compareTo(Car o) { 
            return Double.compare(this.age,o.age);
        }
    
    }

## **Comparator的使用** ##

Dog实体类：

public class Dog { 
        private String name;
        private int age;
    
        public Dog(String name, int age) { 
            this.name = name;
            this.age = age;
        }
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        public int getAge() { 
            return age;
        }
    
        public void setAge(int age) { 
            this.age = age;
        }
    
        @Override
        public String toString() { 
            return "Dog{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    '}';
        }
    }

MyComparator类：

public class MyComparator implements Comparator<Dog> { 
        @Override
        public int compare(Dog o1, Dog o2) { 
            return o1.getAge()-o2.getAge();
        }
    }

测试类：

public class Test { 
        public static void main(String[] args) { 
            Dog[] dogs={ 
                    new Dog("耀龙",30),
                    new Dog("鸡儿龙",18),
                    new Dog("haha",17)
            };
    
            Arrays.sort(dogs,new MyComparator());
            System.out.println(Arrays.toString(dogs));
        }
    }