Spring 启动过程(原理)详细，springmvc加载流程springmvc执行流程 简略

 

spring加载流程
1.监听器加载spring
2.加载配置文件
3.工厂生产实例化对象
4.放入ServletContext


springmvc加载流程
1.Servlet加载（监听器之后即执行）Servlet的init()
2.加载配置文件
3.从ServletContext拿到spring初始化springmvc相关对象
4.放入ServletContext


springmvc执行流程
1.用户请求到DispatcherServlet
2.DispatcherServlet查找HandlerMapping请求Handler并返回查找结果
3.DispatcherServlet调用HandlerAdapter执行Handler并返回执行结果
4.DispatcherServlet调用ResolverView生成视图并返回视图
5.DispatcherServlet返回给用户

 

WEB项目启动时候,加载web.xml,spring会在web.xml中配置启动监听器和启动参数

1. <context-param>

2. <param-name>contextConfigLocation</param-name>

3. <param-value>

4. classpath:spring-*.xml

5. </param-value>

6. </context-param>

7.  

8. <listener>

9. <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

10. </listener>

web容器启动加载spring容器顺序

 

1. 执行web.xml中的ContextLoaderListener监听器
2. 初始化ContextLoaderListener中的contextInitialized方法 

1. /**

2. * Initialize the root web application context.

3. */

4. public void contextInitialized(ServletContextEvent event) {

5. this.contextLoader = createContextLoader();

6. if (this.contextLoader == null) {

7. this.contextLoader = this;

8. }

9. this.contextLoader.initWebApplicationContext(event.getServletContext());

10. }

调用父类的initWebApplicationContext

在initwebapplicationContext中调用了三个方法

创建WebApplicationContext对象 

1. public WebApplicationContext initWebApplicationContext(ServletContext servletContext) {

2. if (servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE) != null) {

3. throw new IllegalStateException(

4. "Cannot initialize context because there is already a root application context present - " +

5. "check whether you have multiple ContextLoader* definitions in your web.xml!");

6. }

7.  

8. Log logger = LogFactory.getLog(ContextLoader.class);

9. servletContext.log("Initializing Spring root WebApplicationContext");

10. if (logger.isInfoEnabled()) {

11. logger.info("Root WebApplicationContext: initialization started");

12. }

13. long startTime = System.currentTimeMillis();

14.  

15. try {

16. // Store context in local instance variable, to guarantee that

17. // it is available on ServletContext shutdown.

18. if (this.context == null) {

19. this.context = createWebApplicationContext(servletContext);

20. }

21. if (this.context instanceof ConfigurableWebApplicationContext) {

22. configureAndRefreshWebApplicationContext((ConfigurableWebApplicationContext)this.context, servletContext);

23. }

24. servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, this.context);

25.  

26. ClassLoader ccl = Thread.currentThread().getContextClassLoader();

27. if (ccl == ContextLoader.class.getClassLoader()) {

28. currentContext = this.context;

29. }

30. else if (ccl != null) {

31. currentContextPerThread.put(ccl, this.context);

32. }

33.  

34. if (logger.isDebugEnabled()) {

35. logger.debug("Published root WebApplicationContext as ServletContext attribute with name [" +

36. WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE + "]");

37. }

38. if (logger.isInfoEnabled()) {

39. long elapsedTime = System.currentTimeMillis() - startTime;

40. logger.info("Root WebApplicationContext: initialization completed in " + elapsedTime + " ms");

41. }

42.  

43. return this.context;

44. }

45. catch (RuntimeException ex) {

46. logger.error("Context initialization failed", ex);

47. servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, ex);

48. throw ex;

49. }

50. catch (Error err) {

51. logger.error("Context initialization failed", err);

52. servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, err);

53. throw err;

54. }

55. }

 

加载context-param中配置的spring配置文件

初始化配置文件中及创建配置文件中的bean

1. /**

2. * Name of servlet context parameter (i.e., {@value}) that can specify the

3. * config location for the root context, falling back to the implementation's

4. * default otherwise.

5. * @see org.springframework.web.context.support.XmlWebApplicationContext#DEFAULT_CONFIG_LOCATION

6. */

7. public static final String CONFIG_LOCATION_PARAM = "contextConfigLocation";

---------------------------------------------------------------------------------------------------------------------完美分割线

web容器停止时候,停止webapplicationContent容器

1. /**

2. * Close the root web application context.

3. */

4. public void contextDestroyed(ServletContextEvent event) {

5. if (this.contextLoader != null) {

6. this.contextLoader.closeWebApplicationContext(event.getServletContext());

7. }

8. ContextCleanupListener.cleanupAttributes(event.getServletContext());

9. }