Spring容器创建对象的三种方式

/*** spring容器做的事情&＃xff1a;* 解析spring的配置文件&＃xff0c;利用Java的反射机制创建对象**/
public class testHelloWorld {&＃64;Testpublic void testHelloWorld(){//启动sping容器ApplicationContext context&＃61;new ClassPathXmlApplicationContext("applicationContext.xml");//从spring容器中把对象提取出来HelloWorld helloWorld&＃61;(HelloWorld)context.getBean("helloWorld");helloWorld.sayHello();HelloWorld alias&＃61;(HelloWorld)context.getBean("三毛");alias.sayHello();}/*** 静态工厂* 在spring 内部&＃xff0c;调用了HelloWorldFactory 内部的 getInstance 内部方法* 而该方法的内容&＃xff0c;就是创建对象的过程&＃xff0c;是由程序员来完成的* 这就是静态工厂* */&＃64;Testpublic void testHelloWorldFactory(){ApplicationContext context&＃61;new ClassPathXmlApplicationContext("applicationContext.xml");HelloWorld helloWorld&＃61;(HelloWorld)context.getBean("helloWorldFactory");helloWorld.sayHello();}/*** 实例工厂* 1.spring容器&＃xff08;beans&＃xff09;创建了一个实例工厂的bean* 2.该bean 调用了工厂方法的getInstance 方法产生对象* */&＃64;Testpublic void testHelloWorldFactory2(){ApplicationContext context&＃61;new ClassPathXmlApplicationContext("applicationContext.xml");HelloWorld helloWorld&＃61;(HelloWorld)context.getBean("helloWorld3");helloWorld.sayHello();}
}

public class HelloWorld {public HelloWorld(){System.out.println("spring 在默认的情况下&＃xff0c;使用默认的构造函数");}public void sayHello(){System.out.println("hello");}
}

public class HelloWorldFactory {public static HelloWorld getInstance(){return new HelloWorld();}
}

public class HelloWorldFactory2 {public HelloWorld getInstance(){return new HelloWorld();}
}


<beans xmlns&＃61;"http://www.springframework.org/schema/beans"xmlns:xsi&＃61;"http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation&＃61;"http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-2.5.xsd"><bean id&＃61;"helloWorld" class&＃61;"com.sanmao.spring.ioc.HelloWorld">bean><alias name&＃61;"helloWorld" alias&＃61;"三毛">alias><bean id&＃61;"helloWorldFactory" class&＃61;"com.sanmao.spring.ioc.HelloWorldFactory"factory-method&＃61;"getInstance">bean><bean id&＃61;"helloWorldFactory2" class&＃61;"com.sanmao.spring.ioc.HelloWorldFactory2">bean><bean id&＃61;"helloWorld3" factory-bean&＃61;"helloWorldFactory2" factory-method&＃61;"getInstance">bean>beans>