初识BeanFactory

初识BeanFactory

作用:用来生产Bean的。

beanFactory是一个接口，他有很多实现，功能非常强大。

public interface BeanFactory {
    String FACTORY_BEAN_PREFIX = "&";

    Object getBean(String var1) throws BeansException;

    <T> T getBean(String var1, Class<T> var2) throws BeansException;

    Object getBean(String var1, Object... var2) throws BeansException;

    <T> T getBean(Class<T> var1) throws BeansException;

    <T> T getBean(Class<T> var1, Object... var2) throws BeansException;

    boolean containsBean(String var1);

    boolean isSingleton(String var1) throws NoSuchBeanDefinitionException;

    boolean isPrototype(String var1) throws NoSuchBeanDefinitionException;

    boolean isTypeMatch(String var1, ResolvableType var2) throws NoSuchBeanDefinitionException;

    boolean isTypeMatch(String var1, Class<?> var2) throws NoSuchBeanDefinitionException;

    Class<?> getType(String var1) throws NoSuchBeanDefinitionException;

    String[] getAliases(String var1);
}

 

 生成bean的方式很多，但是beanFactory是一个容器，里面存的应该是BeanDefinition和对象

public class Main {
    public static void main(String[] args) {
       
        DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
        //方式一：先进行注册  才能获取到bean
        beanFactory.registerSingleton("user",new User());//对象

        //方式二：通过BeanDefinition注册，再获取bean
        AbstractBeanDefinition beanDefinition = BeanDefinitionBuilder.genericBeanDefinition().getBeanDefinition();
        beanDefinition.setBeanClass(User.class);
        beanFactory.registerBeanDefinition("user",beanDefinition);//beanDefinition

        User user = beanFactory.getBean("user",User.class);
        
        
    }
}