上节我们对XmlBeanFactory进行了初步了解
简化版源码：
/** * public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable public XmlBeanDefinitionReader(BeanDefinitionRegistry registry) { super(registry); } protected AbstractBeanDefinitionReader(BeanDefinitionRegistry registry) { this.registry = registry; */ //reader的registry得到初始化值为XmlBeanFactory对象，this指代的就是此时创建的XmlBeanFactory对象 private final XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(this);首先分析一下上面这段代码（调用有参构造函数）；
/** * 在XmlBeanFactory进行了实例化操作，传递XmlBeanFactory对象参数 */ public XmlBeanDefinitionReader(BeanDefinitionRegistry registry) { super(registry); } /** * */ protected AbstractBeanDefinitionReader(BeanDefinitionRegistry registry) { // private final BeanDefinitionRegistry registry;属性初始化XmlBeanFactory对象 this.registry = registry; //private ResourceLoader resourceLoader;赋值 this.resourceLoader = new PathMatchingResourcePatternResolver(); this.environment = new StandardEnvironment();//初始化，创建StandardEnvironment对象 }this.resourceLoader = new PathMatchingResourcePatternResolver();
private final ResourceLoader resourceLoader; /** * 默认构造函数，初始化 * Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader. */ public PathMatchingResourcePatternResolver() { this.resourceLoader = new DefaultResourceLoader(); } /** * Create a new DefaultResourceLoader. */ public DefaultResourceLoader() { this.classLoader = ClassUtils.getDefaultClassLoader(); } /** * 返回类加载器 * Return the default ClassLoader to use: typically the thread context */ public static ClassLoader getDefaultClassLoader() { ClassLoader cl = null; //获得类加载器 cl = Thread.currentThread().getContextClassLoader(); return cl; }返回的是同一个类加载器；
通过以上操作： 我们得到了什么？
private final XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(this); //对象的属性 this.registry = registry; this.resourceLoader = new PathMatchingResourcePatternResolver(); new PathMatchingResourcePatternResolver();对象的属性 this.resourceLoader = new DefaultResourceLoader(); new DefaultResourceLoader();对象的属性 this.classLoader = ClassUtils.getDefaultClassLoader();赋值与ClassPathResource同一个类加载器综上所述：reader可以获取到XmlBeanFactory对象和类加载器！！！ 原版代码：
/** * public class DefaultListableBeanFactory extends AbstractAutowireCapableBeanFactory implements ConfigurableListableBeanFactory, BeanDefinitionRegistry, Serializable public XmlBeanDefinitionReader(BeanDefinitionRegistry registry) { super(registry); } protected AbstractBeanDefinitionReader(BeanDefinitionRegistry registry) { Assert.notNull(registry, "BeanDefinitionRegistry must not be null"); this.registry = registry; */ //reader的registry得到初始化值为XmlBeanFactory对象，this指代的就是此时创建的XmlBeanFactory对象 private final XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(this);首先分析一下上面这段代码（调用有参构造函数）；
/** * 在XmlBeanFactory进行了实例化操作，传递XmlBeanFactory对象参数 * Create new XmlBeanDefinitionReader for the given bean factory. * @param registry the BeanFactory to load bean definitions into, * in the form of a BeanDefinitionRegistry */ public XmlBeanDefinitionReader(BeanDefinitionRegistry registry) { super(registry); } /** * Create a new AbstractBeanDefinitionReader for the given bean factory. * <p>If the passed-in bean factory does not only implement the BeanDefinitionRegistry * interface but also the ResourceLoader interface, it will be used as default * ResourceLoader as well. This will usually be the case for * {@link org.springframework.context.ApplicationContext} implementations. * <p>If given a plain BeanDefinitionRegistry, the default ResourceLoader will be a * {@link org.springframework.core.io.support.PathMatchingResourcePatternResolver}. * <p>If the passed-in bean factory also implements {@link EnvironmentCapable} its * environment will be used by this reader. Otherwise, the reader will initialize and * use a {@link StandardEnvironment}. All ApplicationContext implementations are * EnvironmentCapable, while normal BeanFactory implementations are not. * @param registry the BeanFactory to load bean definitions into, * in the form of a BeanDefinitionRegistry * @see #setResourceLoader * @see #setEnvironment */ protected AbstractBeanDefinitionReader(BeanDefinitionRegistry registry) { Assert.notNull(registry, "BeanDefinitionRegistry must not be null"); // private final BeanDefinitionRegistry registry;属性初始化XmlBeanFactory对象 this.registry = registry; // Determine ResourceLoader to use. //false if (this.registry instanceof ResourceLoader) { this.resourceLoader = (ResourceLoader) this.registry; } else { //private ResourceLoader resourceLoader;赋值 this.resourceLoader = new PathMatchingResourcePatternResolver(); } // Inherit Environment if possible if (this.registry instanceof EnvironmentCapable) { this.environment = ((EnvironmentCapable) this.registry).getEnvironment(); } else { this.environment = new StandardEnvironment();//初始化，创建StandardEnvironment对象 } }this.resourceLoader = new PathMatchingResourcePatternResolver();
private final ResourceLoader resourceLoader; /** * 默认构造函数，初始化 * Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader. * <p>ClassLoader access will happen via the thread context class loader. * @see org.springframework.core.io.DefaultResourceLoader */ public PathMatchingResourcePatternResolver() { this.resourceLoader = new DefaultResourceLoader(); } /** * Create a new DefaultResourceLoader. * <p>ClassLoader access will happen using the thread context class loader * at the time of this ResourceLoader's initialization. * @see java.lang.Thread#getContextClassLoader() */ public DefaultResourceLoader() { this.classLoader = ClassUtils.getDefaultClassLoader(); } /** * 返回类加载器 * Return the default ClassLoader to use: typically the thread context * ClassLoader, if available; the ClassLoader that loaded the ClassUtils * class will be used as fallback. * <p>Call this method if you intend to use the thread context ClassLoader * in a scenario where you clearly prefer a non-null ClassLoader reference: * for example, for class path resource loading (but not necessarily for * {@code Class.forName}, which accepts a {@code null} ClassLoader * reference as well). * @return the default ClassLoader (only {@code null} if even the system * ClassLoader isn't accessible) * @see Thread#getContextClassLoader() * @see ClassLoader#getSystemClassLoader() */ public static ClassLoader getDefaultClassLoader() { ClassLoader cl = null; try { //获得类加载器 cl = Thread.currentThread().getContextClassLoader(); } catch (Throwable ex) { // Cannot access thread context ClassLoader - falling back... } if (cl == null) { // No thread context class loader -> use class loader of this class. cl = ClassUtils.class.getClassLoader(); if (cl == null) { // getClassLoader() returning null indicates the bootstrap ClassLoader try { cl = ClassLoader.getSystemClassLoader(); } catch (Throwable ex) { // Cannot access system ClassLoader - oh well, maybe the caller can live with null... } } } return cl; }返回的是同一个类加载器；
通过以上操作： 我们得到了什么？
private final XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(this); //对象的属性 this.registry = registry; this.resourceLoader = new PathMatchingResourcePatternResolver(); new PathMatchingResourcePatternResolver();对象的属性 this.resourceLoader = new DefaultResourceLoader(); new DefaultResourceLoader();对象的属性 this.classLoader = ClassUtils.getDefaultClassLoader();赋值与ClassPathResource同一个类加载器综上所述：reader可以获取到XmlBeanFactory对象和类加载器！！！
