浅谈springioc实例化bean的三个方法

public class HelloWorld {     public HelloWorld(){    System.out.println("aaaa");  }     public void hello(){    System.out.println("hello world");  }}

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

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://www.springframework.org/schema/beans      http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">  <!--    在这个配置中，spring容器要用默认的构造函数为HelloWorld创建对象   -->  <bean id="helloWorld" class="HelloWorld"></bean>     <!--    采用静态工厂方法创建对象      factory-method为工厂方法   -->   <bean id="helloWorld2" class="HelloWorldFactory" factory-method="getInstance"></bean></beans>

@Test  public void test(){    ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");    HelloWorld world = (HelloWorld)context.getBean("helloWorld2");    world.hello();  }