项目中ApplicationContext
applicationContext说白了就是对beanFactory的扩展,也就是一个spring容器,而且applicationContext是单例的,项目中主要包含一个webApplicationContext和spring的DispatchServlet的一个容器。
一.系统提供数据初始化即build的时候怎么把这些bean注入到spring容器中
因为运行build,这不是一个web工程,不会解析web.xml,所以通过一个ApplicationContextFactory这个工厂类来启动一个spring容器:
public final class ApplicationContextFactory { private static ApplicationContextFactory instance; private Map<String,ApplicationContext> contexts=new HashMap<String,ApplicationContext>(); private ApplicationContextFactory(){ } public static ApplicationContextFactory getInstance(){ if (instance==null){ instance=new ApplicationContextFactory(); } return instance; } public ApplicationContext getApplicationContext(){ String type=System.getProperty("spring.profiles.active"); ApplicationContext result=contexts.get(type); if (result==null){ result=new ClassPathXmlApplicationContext( "classpath*:/applicationContext.xml"); contexts.put(type, result); } return result; } public Object getBean(String beanName){ return getApplicationContext().getBean(beanName); } }
注入各个applicationContext.xml的bean,然后在build中执行这些相关bean的init方法。
@Component @AppInitRunner public class SystemBuild extends InitializationsRunner { @Autowired private DatabaseInitManager databaseInitManager; @Autowired private SessionInitManager sessionInitManager; @Autowired private PropertiesInitManager propertiesInitManager; @Autowired private PermissionInitManager permissionInitManager; @Autowired private OrganizationInitManager organizationInitManager; @Autowired private RoleInitManager roleInitManager; @Autowired private JobInitManager jobInitManager; @Autowired private ProcessInitManager processInitManager; @Autowired private MemcachedClient memcachedClient; @Override public void executeInitialization() throws Exception { memcachedClient.flushAll(); databaseInitManager.init(); sessionInitManager.init(); propertiesInitManager.init(); permissionInitManager.init(); organizationInitManager.init(); roleInitManager.init(); jobInitManager.init(); processInitManager.init(); memcachedClient.shutdown(); System.exit(0); } public static void building(String[] args) { try { Map<String, Object> map = ApplicationContextFactory.getInstance() .getApplicationContext() .getBeansWithAnnotation(AppInitRunner.class); for (Entry<String, Object> entry : map.entrySet()) { ((InitializationsRunner) entry.getValue()) .executeInitialization(); } } catch (Exception e) { e.printStackTrace(); } } }
二.web工程加载ApplicationContext
1.在web.xml中通过listener启动容器,这个webApplicationContext即rootContext,这里面主要是管理各个applicationContext.xml中注入的bean主要是一些工具类,DAO等
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
classpath*:/applicationContext.xml
</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
2.spring 本身的DispatchServlet就有一个容器,这个主要用来管理spring-mvc.xml中的bean,还有包括系统中打上@component/controller/service等的bean(主要是service&&controller)。这个Applicationcontext的parentContext就是上面提到的rootContext ,当子applicationContext中找不到相关bean时,会自动去父applicationContext中去寻找。