Spring中Bean的生命週期有singleton prototype request session global session application，預設的生命週期是singleton在容器中永遠都只有一份例項，prototype是原型模式即每一次呼叫都生產一個新的Bean例項。requestsessionglobal sessionapplication是和web應用相關的。

public interface ConfigurableBeanFactory extends HierarchicalBeanFactory, SingletonBeanRegistry {

	/**
	 * Scope identifier for the standard singleton scope: "singleton".
	 * Custom scopes can be added via {@code registerScope}.
	 * @see #registerScope
	 */
	String SCOPE_SINGLETON = "singleton";

	/**
	 * Scope identifier for the standard prototype scope: "prototype".
	 * Custom scopes can be added via {@code registerScope}.
	 * @see #registerScope
	 */
	String SCOPE_PROTOTYPE = "prototype";
 

public interface WebApplicationContext extends ApplicationContext {

	/**
	 * Context attribute to bind root WebApplicationContext to on successful startup.
	 * <p>Note: If the startup of the root context fails, this attribute can contain
	 * an exception or error as value. Use WebApplicationContextUtils for convenient
	 * lookup of the root WebApplicationContext.
	 * @see org.springframework.web.context.support.WebApplicationContextUtils#getWebApplicationContext
	 * @see org.springframework.web.context.support.WebApplicationContextUtils#getRequiredWebApplicationContext
	 */
	String ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE = WebApplicationContext.class.getName() + ".ROOT";

	/**
	 * Scope identifier for request scope: "request".
	 * Supported in addition to the standard scopes "singleton" and "prototype".
	 */
	String SCOPE_REQUEST = "request";

	/**
	 * Scope identifier for session scope: "session".
	 * Supported in addition to the standard scopes "singleton" and "prototype".
	 */
	String SCOPE_SESSION = "session";

	/**
	 * Scope identifier for global session scope: "globalSession".
	 * Supported in addition to the standard scopes "singleton" and "prototype".
	 */
	String SCOPE_GLOBAL_SESSION = "globalSession";

	/**
	 * Scope identifier for the global web application scope: "application".
	 * Supported in addition to the standard scopes "singleton" and "prototype".
	 */
	String SCOPE_APPLICATION = "application";