策略模式定义了一系列的算法，并将每一个算法封装起来，而且使它们还可以相互替换。策略模式让算法独立于使用它的客户而独立变化。（原文：The Strategy Pattern defines a family of algorithms,encapsulates each one,and makes them interchangeable. Strategy lets the algorithm vary independently from clients that use it.）

   1: public class Person {

   2:  

   3:     private String name;

   4:     private int age;

   5:     

   6:     public Person() {

   7:         

   8:     }

   9:     

  10:     public Person(String name, int age) {

  11:         this.name = name;

  12:         this.age = age;

  13:     }

  14:  

  15:     public String getName() {

  16:         return name;

  17:     }

  18:  

  19:     public void setName(String name) {

  20:         this.name = name;

  21:     }

  22:  

  23:     public int getAge() {

  24:         return age;

  25:     }

  26:  

  27:     public void setAge(int age) {

  28:         this.age = age;

  29:     }

  30:  

  31:     @Override

  32:     public String toString() {

  33:         return "Person [age=" + age + ", name=" + name + "]";

  34:     }

  35:  

  36: }

   1: import java.util.Comparator;

   2:  

   3: public class PersonComparator implements Comparator<Person> {

   4:  

   5:     @Override

   6:     public int compare(Person p1, Person p2) {

   7:         if (p1.getAge() > p2.getAge()) {

   8:             return 1;

   9:         } else if (p1.getAge() < p2.getAge()) {

  10:             return -1;

  11:         }

  12:         return 0;

  13:     }

  14:     

  15: }

   1: import java.util.Arrays;

   2:  

   3: public class CompareTest {

   4:  

   5:     public static void main(String[] args) {

   6:         Person[] persons = {

   7:                 new Person("P1", 60),

   8:                 new Person("P2", 20),

   9:                 new Person("P3", 40)

  10:         };

  11:         

  12:         System.out.println(Arrays.toString(persons));

  13:         

  14:         Arrays.sort(persons, new PersonComparator());

  15:         

  16:         System.out.println(Arrays.toString(persons));

  17:     }

  18:  

  19: }