Java 單例及多例

標籤：

一、單例的作用是用於控制類的產生方式，而不讓外部類任意new對象

1.Car.java

import java.util.ArrayList;import java.util.List;public class Car {//私人化建構函式，防止被外部的類newprivate Car() {}private static Car car = new Car();//單例private static List<Car> cars = new ArrayList<Car>();//多例，類似串連池public static Car getInstance() {return car;}public void run() {System.out.println("Car running...............");}}

　　

2.Test.java

public class Test {@org.junit.Testpublic void test() {Car car = Car.getInstance();car.run();Car car2 = Car.getInstance();System.out.println(car == car2);System.out.println(car.equals(car2));}}

　　

運行結果：

Java 單例及多例