bean的作用域
ioc容器默认bean是单例的(singleton)。
bean对象的创建是在初始化上下文的时候就创建了,每一次调用getBean()时,都返回那个单例对象。- // 这行代码会创建配置里面的bean对象
- ApplicationContext context = new FileSystemXmlApplicationContext("D:/applicationContext.xml");
复制代码 那如何把bean设置成多例的?- [/code][code]// 由于这个bean是多例模式,这行代码不会创建bean对象。而是在调用getBean()时创建对象
- ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml","spring-dao.xml");
- // 这行代码才会创建bean对象
- Object user= <bean id="starBean" factory-method="createStar"></bean>context.getBean("sb");
复制代码- <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>
复制代码 自定义scope
- 自定义Scope(实现Scope接口)
- spring内置了线程范围类: org.springframework.context.support.SimpleThreadScope
- 添加配置信息
- <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>
复制代码 GoF之工厂模式
工厂模式的三种形态
- 简单工厂模式(Simple Factory):又叫静态工厂方法模式。是工厂方法模式的一种特殊实现。
- 工厂方法模式 (Factory Method)
- 抽象工厂模式 (Abstract Factory)
简单工厂模式
简单工厂模式包括三个角色:抽象产品、具体产品、工厂类。代码如下:
- // 抽象产品角色
- public abstract class Weapon {
- public abstract void attack();
- }
复制代码
- 具体产品
- // 具体产品角色:匕首public class Dagger extends Weapon{ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public void attack() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>System.out.println("匕首攻击..."); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码
- // 具体产品角色:战斗机public class Fighter extends Weapon{ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public void attack() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>System.out.println("战斗机攻击..."); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码- // 具体产品角色:坦克public class Tank extends Weapon{ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public void attack() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean>System.out.println( "坦克攻击。。。"); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码- // 工厂类角色public class WeaponFactory { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>/** <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> * 静态方法:根据传入的参数获取相应的武器 <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> * @return <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> */ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public static Weapon get(String type){ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>switch (type){ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>case "Tank": <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Tank(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>case "Fighter": <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Fighter(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>case "Dagger": <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Dagger(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>default: <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return null; <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>} <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码 测试代码:- public class Main { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public static void main(String[] args) { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>// 简单工厂模式达到职责分离。客户端不关心产品生产的细节 <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>// 客户端只负责消费,工厂类负责生产。这就是简单工厂模式的作用。 <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>Weapon weapon1 = WeaponFactory.get("Tank"); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>weapon1.attack(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>Weapon weapon2 = WeaponFactory.get("Fighter"); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>weapon2.attack(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>Weapon weapon3 = WeaponFactory.get("Dagger"); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>weapon3.attack(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码 优缺点:
优点:实现职责分离。
缺点:假如要添加新产品。需要修改工厂类代码。显然违反了ocp原则。
<bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>工厂类责任重大。一旦瘫痪,这个系统必然瘫痪。
工厂方法模式
工厂方法模式保留了简单工厂模式的优点。同时解决了简单工厂模式的缺点。
解决方法是:一个工厂对应一个产品。符合ocp原则。
优点:扩展性高。要想增加一个产品。只要扩展一个工厂类就可以。缺点:会使类的数量成倍增加,增加系统复杂度。
工厂方法模式的角色包括:
- 抽象工厂角色
- 具体工厂角色
- 抽象产品角色
- 具体产品角色
代码如下:- // 抽象产品角色public abstract class Weapon { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public abstract void attack();}// 具体产品角色:匕首public class Dagger extends Weapon { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public void attack() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>System.out.println("匕首攻击..."); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}// 具体工厂类:枪械工厂public class GunFactory extends WeaponFactory{ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public Weapon get() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Gun(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}// 抽象工厂类public abstract class WeaponFactory { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public abstract Weapon get();}// 具体工厂类:匕首工厂public class DaggerFactory extends WeaponFactory{ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public Weapon get() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Dagger(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}// 具体工厂类:枪械工厂public class GunFactory extends WeaponFactory{ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public Weapon get() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Gun(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码 测试代码:- public static void main(String[] args) { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>WeaponFactory weaponFactory = new DaggerFactory(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>Weapon dagger = weaponFactory.get(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>dagger.attack(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>WeaponFactory weaponFactory1 = new GunFactory(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>Weapon gun = weaponFactory1.get(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>gun.attack();}
复制代码 bean的实例化
spring为bean提供了多种实例化的方式,通常包括4种方式。
- 通过构造方法实例化
- 通过简单工厂模式实例化
- 通过factory-bean实例化
- 通过FactoryBean接口实例化
通过构造方法实例化
- <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>
复制代码 通过简单工厂模式实例化
- // 工厂类public class StarFactory { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public static Star createStar() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Star(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码- <bean id="starBean" factory-method="createStar"></bean>
复制代码 通过factory-bean实例化
- // 工厂方法模式中的具体产品类public class Gun { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public Gun() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>System.out.println("无参数构造器:Gun()"); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}// 工厂方法模式中的具体工厂类public class GunFactory { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public Gun get(){ <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Gun(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码- <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>
复制代码 通过FactoryBean接口实例化
通过factory-bean实例化的方式需要我们自定义factory-bean和factory-method。
在spring中,当自己的类实现了FactoryBean接口后factory-bean和factory-method就不需要指定了。factory-bean会自动指向实现FactoryBean接口的类,factory-method会自动指向getObject()方法。- public class PersonFactoryBean implements FactoryBean { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public Person getObject() throws Exception { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>// 手动创建对象 <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return new Person(); <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>} <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>@Override <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>public Class getObjectType() { <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/> <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>return null; <bean id="starBean" factory-method="createStar"></bean> <bean id="starBean" factory-method="createStar"></bean><bean id="springBean" <bean id="starBean" factory-method="createStar"></bean>/><bean id="sb" <bean id="starBean" factory-method="createStar"></bean> scope="prototype"/>}}
复制代码 [code][/code]BeanFactory和FactoryBean的区别
BeanFactory:spring ioc容器的顶级对象,负责创建bean对象。BeanFactory是工厂
FactoryBean:本质是一个bean。能够辅助spring实例化其他bean对象。
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