comparable和comparator的区别（代码实现比较两个person）

本文主要是介绍comparable和comparator的区别（代码实现比较两个person），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

两者都是java的比较器。不过 comparable，需要被比较的类自己去实现排序逻辑；comparator不需要。

Comparator和Comparable的区别

参数	Comparable	Comparator
排序逻辑	排序逻辑必须在待排序对象的类中，故称之为自然排序	排序逻辑在另一个实现
实现	实现Comparable接口	实现Comparator接口
排序方法	`int compareTo(Object o1)`	`int compare(Object o1,Object o2)`
触发排序	Collections.sort(List)	Collections.sort(List, Comparator)
接口所在包	`java.lang.Comparable`	`java.util.Comparator`

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实现比较person,先按年龄排，年龄相同的按工资排。

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1.comparable 实现。（person类实现Comparable接口，实现比较方法compareTo，比较时使用Conllections.sort(list)即可）

package com.fjf.test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
*
* 2018年7月14日 23:22:21
* @author FJf
*
* 比较大小，按年龄从小到大，年龄相同的；按工资多少排
* Comparable 需要被比较的对象自己实现比较的方法
*/
public class TestComparable {

   public static void main(String[] args) {
       List<Person> list = new ArrayList<Person>();
       list.add(new Person("张三", 50,"男",500.00));
       list.add(new Person("李四", 27,"女",800.00));
       list.add(new Person("王五", 33,"男",500.00));
       list.add(new Person("赵六", 33,"男",1000.00));
       list.add(new Person("付8", 33,"男",500.00));

       for (Person p : list) {
               System.out.println(p);
           }

       System.out.println("--------Comparable比较----------");

       Collections.sort(list);

       for (Person p : list) {
           System.out.println(p);
       }


   }
}

class Person implements Comparable<Person>{
   private String name;

private int age;

private String sex;

private double salary;

   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;
   }

   public String getSex() {
       return sex;
   }

   public void setSex(String sex) {
       this.sex = sex;
   }

   public double getSalary() {
       return salary;
   }

   public void setSalary(double salary) {
       this.salary = salary;
   }

   public Person(String name, int age, String sex,double salary) {
       super();
       this.name = name;
       this.age = age;
       this.sex = sex;
       this.salary = salary;
   }

   public Person() {
       super();
   }

   @Override
   public int compareTo(Person o) {

       int ageCompare = this.age - o.age;

       if(ageCompare==0){ //年龄相同用工资排
           int salaryCompare = (this.salary - o.salary)>0.00?-1:1; //工资如果再相同就不管了
           System.out.println(salaryCompare);
           return salaryCompare;
       }
       return ageCompare;

       //return o.age -this.age;
       //this.compareTo(o.age);
       //this.getAge().compareTo(o.getAge());
       //this.name.compareTo(anotherString)
   }

   @Override
   public String toString() {
       return "Person [name=" + name + ", age=" + age + ", sex=" + sex
               + ", salary=" + salary + "]";
   }

}

--------------------------------

2.comparator实现。(pesron类自己无需实现任何比较逻辑。在真正比较时，Conllections.sort(list,Comparator)在传入一个comparator比较器实现比较逻辑)

package com.fjf.test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
*
* 2018年7月14日 23:42:30
* @author fjf
*
* 使用comparator比较
*/
public class TestComparator {


   public static void main(String[] args) {
       List<Person2> list = new ArrayList<Person2>();
       list.add(new Person2("张三", 50,"男",500.00));
       list.add(new Person2("李四", 27,"女",800.00));
       list.add(new Person2("王五", 33,"男",500.00));
       list.add(new Person2("赵六", 33,"男",1000.00));
       list.add(new Person2("付8", 33,"男",500.00));

       for (Person2 p : list) {
               System.out.println(p);
           }

       System.out.println("---------Comparator比较----------");

       Collections.sort(list, new Comparator<Person2>() {

           @Override
           public int compare(Person2 o1, Person2 o2) {
               int ageCompare = o1.getAge()-o2.getAge();
               if(ageCompare == 0){
                   int salaryCompare = (o1.getSalary()-o2.getSalary()>0.00?1:-1);
                   return salaryCompare;
               }
               return ageCompare;
           }
       });

       for (Person2 p : list) {
               System.out.println(p);
           }


   }


}
   class Person2 {
       private String name;

   private int age;

   private String sex;

   private double salary;

       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;
       }

       public String getSex() {
           return sex;
       }

       public void setSex(String sex) {
           this.sex = sex;
       }

       public double getSalary() {
           return salary;
       }

       public void setSalary(double salary) {
           this.salary = salary;
       }

       public Person2(String name, int age, String sex, double salary) {
           super();
           this.name = name;
           this.age = age;
           this.sex = sex;
           this.salary = salary;
       }

       public Person2() {
           super();
       }

       @Override
       public String toString() {
           return "Person [name=" + name + ", age=" + age + ", sex=" + sex
                   + ", salary=" + salary + "]";
       }

   }