重看Spring聚焦BeanFactory分析

BeanFactory是Spring框架的核心接口，它是工厂模式的实现，负责生产和管理bean对象。以下是BeanFactory的一个简单实现示例：

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
 
import java.util.HashMap;
import java.util.Map;
 
public class SimpleBeanFactory implements BeanFactory {
 
    private final DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
    private final Map<String, Object> singletonObjects = new HashMap<>();
 
    public SimpleBeanFactory(String[] configLocations) {
        XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(beanFactory);
        for (String location : configLocations) {
            reader.loadBeanDefinitions(location);
        }
    }
 
    @Override
    public Object getBean(String name) throws Exception {
        return doGetBean(name);
    }
 
    @Override
    public <T> T getBean(String name, Class<T> requiredType) throws Exception {
        return (T) getBean(name);
    }
 
    @Override
    public Object getBean(String name, Object... args) throws Exception {
        return doGetBean(name);
    }
 
    @Override
    public <T> T getBean(Class<T> requiredType) throws Exception {
        return beanFactory.getBean(requiredType);
    }
 
    @Override
    public <T> T getBean(Class<T> requiredType, Object... args) throws Exception {
        return beanFactory.getBean(requiredType);
    }
 
    @Override
    public boolean containsBean(String name) {
        return beanFactory.containsBean(name);
    }
 
    @Override
    public boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
        BeanDefinition beanDefinition = beanFactory.getBeanDefinition(name);
        return beanDefinition.isSingleton();
    }
 
    @Override
    public boolean isPrototype(String name) throws NoSuchBeanDefinitionException {
        BeanDefinition beanDefinition = beanFactory.getBeanDefinition(name);
        return beanDefinition.isPrototype();
    }
 
    @Override