模板模式中，父类规定好了一些算法的流程，并且空出一些步骤（方法）留给子类填充
Java的数组类中静态方法sort()就是一个模板，它空出了一个compareTo的方法，留给子类填充，用来规定什么是大于、等于和小于
package com.example.template;
public class Duck implements Comparable<Duck>{
private String name;
private int weight;
public Duck(String name, int weight){
this.name = name;
this.weight = weight;
}
public String toString(){
return "name" + name + "weight" + weight;
}
@Override
public int compareTo(Duck other) {
if(this.weight < other.weight){
return -1;
}else if(this.weight > other.weight){
return 1;
}
return 0;
}
}package com.example.template;
import java.util.Random;
public class Employee implements Comparable<Employee> {
private String name;
private int id;
private double salary;
public Employee(String name, double salary){
this.name = name;
this.salary = salary;
Random ra = new Random();
this.id = ra.nextInt(1000000);
}
public String toString(){
return "name:" + name + " salary:" + salary + " ElyId:" + id;
}
@Override
public int compareTo(Employee other) {
if(this.id < other.id){
return -1;
}else if(this.id > other.id){
return 1;
}
return 0;
}
}package com.example.template;
import java.util.Arrays;
public class Test {
public static void main(String[] args)
{
Duck[] ducks = new Duck[4];
ducks[0] = new Duck("Jason", 89);
ducks[1] = new Duck("Amemle", 100);
ducks[2] = new Duck("Mike", 72);
ducks[3] = new Duck("Ham", 102);
System.out.println("before sort:");
for(int i = 0 ; i < ducks.length ; i++)
System.out.println(ducks[i].toString());
Arrays.sort(ducks);
System.out.println("after sort:");
for(int i = 0 ; i < ducks.length ; i++)
System.out.println(ducks[i].toString());
Employee[] emps = {
new Employee("Jason", 999.0),
new Employee("Canson", 1599.1),
new Employee("Jack", 887.9)
};
System.out.println("--------------------");
System.out.println("before sort:");
for(int i = 0 ; i < emps.length ; i++)
System.out.println(emps[i].toString());
Arrays.sort(emps);
System.out.println("after sort:");
for(int i = 0 ; i < emps.length ; i++)
System.out.println(emps[i].toString());
}
}结果：
before sort:
nameJasonweight89
nameAmemleweight100
nameMikeweight72
nameHamweight102
after sort:
nameMikeweight72
nameJasonweight89
nameAmemleweight100
nameHamweight102
--------------------
before sort:
name:Jason salary:999.0 ElyId:502862
name:Canson salary:1599.1 ElyId:716871
name:Jack salary:887.9 ElyId:552929
after sort:
name:Jason salary:999.0 ElyId:502862
name:Jack salary:887.9 ElyId:552929
name:Canson salary:1599.1 ElyId:716871