社区 › 业界 › spring6-工厂设计模式与bean的实例化方式

史穹逊 发表于 2 小时前

spring6-工厂设计模式与bean的实例化方式

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");那如何把bean设置成多例的？
// 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");<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"/>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"/>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：

[*]抽象产品类
// 抽象产品角色
public abstract class Weapon {
        public abstract void attack();
}
[*]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"/>}}
// 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"/>}}// 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"/>}}
[*]工厂类角色
// 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"/>}}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"/>}}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。
        屏蔽产品具体实现。调用者只关心产品的接口。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"/>}}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();}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"/>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"/>}}<bean id="starBean"factory-method="createStar"></bean>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"/>}}<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"/>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"/>}}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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