本文主要是介绍Spring源码学习--ClassPathXmlApplicationContext+FileSystemXmlApplicationContext+XmlWebApplicationContext，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
文章来源:
1 https://blog.csdn.net/qq924862077/article/details/59090521
2 https://blog.csdn.net/qq924862077/article/details/58653218
3 https://blog.csdn.net/qq924862077/article/details/58650318
一 ClassPathXmlApplicationContext
在实现类ClassPathXmlApplicationContext中其实并没有多少重要的操作，主要是在构造函数中配置Spring配置文件的路径：
public class DaoOperationMain { public static void main(String[] args) { ApplicationContext appCtx = new ClassPathXmlApplicationContext("applicationContext.xml"); }
} 具体的applicationContext.xml解析相关的操作都在父类refresh中进行操作。
/** * 并没有太多具体的操作，主要是初始化构造函数，主要的操作都在父类中 */
public class ClassPathXmlApplicationContext extends AbstractXmlApplicationContext { private Resource[] configResources; public ClassPathXmlApplicationContext() { } public ClassPathXmlApplicationContext(ApplicationContext parent) { super(parent); } public ClassPathXmlApplicationContext(String configLocation) throws BeansException { this(new String[] {configLocation}, true, null); } public ClassPathXmlApplicationContext(String... configLocations) throws BeansException { this(configLocations, true, null); } public ClassPathXmlApplicationContext(String[] configLocations, ApplicationContext parent) throws BeansException { this(configLocations, true, parent); } public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh) throws BeansException { this(configLocations, refresh, null); } public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent) throws BeansException { super(parent); //设置spring的配置文件 setConfigLocations(configLocations); if (refresh) { //调用父类的refresh函数，进行一系列初始化 refresh(); } } public ClassPathXmlApplicationContext(String path, Class<?> clazz) throws BeansException { this(new String[] {path}, clazz); } public ClassPathXmlApplicationContext(String[] paths, Class<?> clazz) throws BeansException { this(paths, clazz, null); } public ClassPathXmlApplicationContext(String[] paths, Class<?> clazz, ApplicationContext parent) throws BeansException { super(parent); Assert.notNull(paths, "Path array must not be null"); Assert.notNull(clazz, "Class argument must not be null"); this.configResources = new Resource[paths.length]; for (int i = 0; i < paths.length; i++) { this.configResources[i] = new ClassPathResource(paths[i], clazz); } //调用父类的refresh函数，进行一系列初始化 refresh(); } @Override protected Resource[] getConfigResources() { return this.configResources; } } 二 FileSystemXmlApplicationContext
FileSystemXmlApplicationContext的源码如下：
/** * 并没有太多具体的操作，很多初始化操作都在其父类中 */
public class FileSystemXmlApplicationContext extends AbstractXmlApplicationContext { public FileSystemXmlApplicationContext() { } public FileSystemXmlApplicationContext(ApplicationContext parent) { super(parent); } public FileSystemXmlApplicationContext(String configLocation) throws BeansException { this(new String[] {configLocation}, true, null); } public FileSystemXmlApplicationContext(String... configLocations) throws BeansException { this(configLocations, true, null); } public FileSystemXmlApplicationContext(String[] configLocations, ApplicationContext parent) throws BeansException { this(configLocations, true, parent); } public FileSystemXmlApplicationContext(String[] configLocations, boolean refresh) throws BeansException { this(configLocations, refresh, null); } public FileSystemXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent) throws BeansException { //调用父类的构造函数 super(parent); //设置配置文件的地址，如application.xml setConfigLocations(configLocations); if (refresh) { //刷新容器，其实就是重新初始化容器 refresh(); } } @Override protected Resource getResourceByPath(String path) { if (path != null && path.startsWith("/")) { path = path.substring(1); } return new FileSystemResource(path); }
} 三 XmlWebApplicationContext
XmlWebApplicationContext是用于web容器的应用上下文的，其也没有太多操作，主要还是applicationContext.xml的解析操作，完整源码如下:
public class XmlWebApplicationContext extends AbstractRefreshableWebApplicationContext { /** Default config location for the root context */ //默认配置文件地址 public static final String DEFAULT_CONFIG_LOCATION = "/WEB-INF/applicationContext.xml"; /** Default prefix for building a config location for a namespace */ public static final String DEFAULT_CONFIG_LOCATION_PREFIX = "/WEB-INF/"; /** Default suffix for building a config location for a namespace */ public static final String DEFAULT_CONFIG_LOCATION_SUFFIX = ".xml"; //解析applicationContext.xml @Override protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException { // Create a new XmlBeanDefinitionReader for the given BeanFactory. XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory); // Configure the bean definition reader with this context's // resource loading environment. beanDefinitionReader.setEnvironment(getEnvironment()); beanDefinitionReader.setResourceLoader(this); beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this)); // Allow a subclass to provide custom initialization of the reader, // then proceed with actually loading the bean definitions. initBeanDefinitionReader(beanDefinitionReader); loadBeanDefinitions(beanDefinitionReader); } protected void initBeanDefinitionReader(XmlBeanDefinitionReader beanDefinitionReader) { } protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws IOException { String[] configLocations = getConfigLocations(); if (configLocations != null) { for (String configLocation : configLocations) { reader.loadBeanDefinitions(configLocation); } } } //获取默认配置文件地址 @Override protected String[] getDefaultConfigLocations() { if (getNamespace() != null) { return new String[] {DEFAULT_CONFIG_LOCATION_PREFIX + getNamespace() + DEFAULT_CONFIG_LOCATION_SUFFIX}; } else { return new String[] {DEFAULT_CONFIG_LOCATION}; } } 这篇关于Spring源码学习--ClassPathXmlApplicationContext+FileSystemXmlApplicationContext+XmlWebApplicationContext的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
