WebApplicationContextUtils源码

package org.springframework.web.context.support;

import javax.servlet.ServletContext;

import javax.servlet.ServletRequest;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpSession;

import org.springframework.beans.factory.ObjectFactory;

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;

import org.springframework.util.Assert;

import org.springframework.web.context.WebApplicationContext;

import org.springframework.web.context.request.RequestAttributes;

import org.springframework.web.context.request.RequestContextHolder;

import org.springframework.web.context.request.RequestScope;

import org.springframework.web.context.request.ServletRequestAttributes;

import org.springframework.web.context.request.SessionScope;

public abstract class WebApplicationContextUtils

{

  public static WebApplicationContext getRequiredWebApplicationContext(ServletContext sc)

    throws IllegalStateException

  {

    WebApplicationContext wac = getWebApplicationContext(sc);

    if (wac == null) {

      throw new IllegalStateException("No WebApplicationContext found: no ContextLoaderListener registered?");

    }

    return wac;

  }

  public static WebApplicationContext getWebApplicationContext(ServletContext sc)

  {

    return getWebApplicationContext(sc, WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);

  }

  public static WebApplicationContext getWebApplicationContext(ServletContext sc, String attrName)

  {

    Assert.notNull(sc, "ServletContext must not be null");

    Object attr = sc.getAttribute(attrName);

    if (attr == null) {

      return null;

    }

    if ((attr instanceof RuntimeException)) {

      throw ((RuntimeException)attr);

    }

    if ((attr instanceof Error)) {

      throw ((Error)attr);

    }

    if ((attr instanceof Exception)) {

      IllegalStateException ex = new IllegalStateException();

      ex.initCause((Exception)attr);

      throw ex;

    }

    if (!(attr instanceof WebApplicationContext)) {

      throw new IllegalStateException("Context attribute is not of type WebApplicationContext: " + attr);

    }

    return (WebApplicationContext)attr;

  }

  public static void registerWebApplicationScopes(ConfigurableListableBeanFactory beanFactory)

  {

    beanFactory.registerScope("request", new RequestScope());

    beanFactory.registerScope("session", new SessionScope(false));

    beanFactory.registerScope("globalSession", new SessionScope(true));

    beanFactory.registerResolvableDependency(ServletRequest.class, new ObjectFactory() {

      public Object getObject() {

        RequestAttributes requestAttr = RequestContextHolder.currentRequestAttributes();

        if (!(requestAttr instanceof ServletRequestAttributes)) {

          throw new IllegalStateException("Current request is not a servlet request");

        }

        return ((ServletRequestAttributes)requestAttr).getRequest();

      }

    });

    beanFactory.registerResolvableDependency(HttpSession.class, new ObjectFactory() {

      public Object getObject() {

        RequestAttributes requestAttr = RequestContextHolder.currentRequestAttributes();

        if (!(requestAttr instanceof ServletRequestAttributes)) {

          throw new IllegalStateException("Current request is not a servlet request");

        }

        return ((ServletRequestAttributes)requestAttr).getRequest().getSession();

      }

    });

  }

}