S2S3H4框架深度集成搭建(2) Spring的深度集成

 

上 一篇，写了struts2中的关键问题，至于详细的集成过程，我就不细表了，除了我描述的关键问题以外，其他的都雷同。下面说说Spring的集成，网上 搜的文章中大多介绍spring和struts2的集成，都是同一套路，将spring的配置往src根目录一扔，然后在web.xml中配个监听器，然 后在struts2的配置中增加struts.objectFactory的描述。就完了，虽然好用，但是都是照葫芦画瓢，不知所以然。其实struts 既然有这个个描述，那就意味着，struts2中所有实例的获取，都要通过这个定义的ObjectFactory来获取，工厂里用什么方式获取对象就和什 么集成，所以，和spring的集成关键不在web.xml的配置上，甚至web.xml上的监听可以完全不要。下面我们就来实际的做一下：编写 XKStrutsSpringObjectFactory继承SpringObjectFactory， 代码如下：

public class XKStrutsSpringObjectFactory extends SpringObjectFactory
{
    /**
     *
     */
    private static final long serialVersionUID = 1L;
    private static final Logger LOG = LoggerFactory.getLogger(XKStrutsSpringObjectFactory.class);


    @SuppressWarnings("deprecation")
    @Inject
    public XKStrutsSpringObjectFactory(@Inject(value = StrutsConstants.STRUTS_OBJECTFACTORY_SPRING_AUTOWIRE, required = false) String autoWire,
            @Inject(value = StrutsConstants.STRUTS_OBJECTFACTORY_SPRING_AUTOWIRE_ALWAYS_RESPECT, required = false) String alwaysAutoWire,
            @Inject(value = StrutsConstants.STRUTS_OBJECTFACTORY_SPRING_USE_CLASS_CACHE, required = false) String useClassCacheStr, @Inject ServletContext servletContext,
            @Inject(StrutsConstants.STRUTS_DEVMODE) String devMode, @Inject Container container)
    {

        super();
        boolean useClassCache = "true".equals(useClassCacheStr);
        if (LOG.isInfoEnabled())
        {
            LOG.info("Initializing Struts-Spring integration...");
        }

  // 关键代码
        Object rootWebApplicationContext = Initialization.getInstance().getApplicationContext();

        if (rootWebApplicationContext instanceof RuntimeException)
        {
            RuntimeException runtimeException = (RuntimeException) rootWebApplicationContext;
            LOG.fatal(runtimeException.getMessage());
            return;
        }

        ApplicationContext appContext = (ApplicationContext) rootWebApplicationContext;
        if (appContext == null)
        {
            // uh oh! looks like the lifecycle listener wasn't installed. Let's
            // inform the user
            String message = "********** FATAL ERROR STARTING UP STRUTS-SPRING INTEGRATION **********\n" + "Looks like the Spring listener was not configured for your web app! \n"
                    + "Nothing will work until WebApplicationContextUtils returns a valid ApplicationContext.\n" + "You might need to add the following to web.xml: \n" + "    <listener>\n"
                    + "        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>\n" + "    </listener>";
            LOG.fatal(message);
            return;
        }

        String watchList = container.getInstance(String.class, "struts.class.reloading.watchList");
        String acceptClasses = container.getInstance(String.class, "struts.class.reloading.acceptClasses");
        String reloadConfig = container.getInstance(String.class, "struts.class.reloading.reloadConfig");

        if ("true".equals(devMode) && StringUtils.isNotBlank(watchList) && appContext instanceof ClassReloadingXMLWebApplicationContext)
        {
            // prevent class caching
            useClassCache = false;

            ClassReloadingXMLWebApplicationContext reloadingContext = (ClassReloadingXMLWebApplicationContext) appContext;
            reloadingContext.setupReloading(watchList.split(","), acceptClasses, servletContext, "true".equals(reloadConfig));
            if (LOG.isInfoEnabled())
            {
                LOG.info("Class reloading is enabled. Make sure this is not used on a production environment!", watchList);
            }

            setClassLoader(reloadingContext.getReloadingClassLoader());

            // we need to reload the context, so our isntance of the factory is
            // picked up
            reloadingContext.refresh();
        }

        this.setApplicationContext(appContext);

        int type = AutowireCapableBeanFactory.AUTOWIRE_BY_NAME; // default
        if ("name".equals(autoWire))
        {
            type = AutowireCapableBeanFactory.AUTOWIRE_BY_NAME;
        }
        else if ("type".equals(autoWire))
        {
            type = AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE;
        }
        else if ("auto".equals(autoWire))
        {
            type = AutowireCapableBeanFactory.AUTOWIRE_AUTODETECT;
        }
        else if ("constructor".equals(autoWire))
        {
            type = AutowireCapableBeanFactory.AUTOWIRE_CONSTRUCTOR;
        }
        else if ("no".equals(autoWire))
        {
            type = AutowireCapableBeanFactory.AUTOWIRE_NO;
        }
        this.setAutowireStrategy(type);

        this.setUseClassCache(useClassCache);

        this.setAlwaysRespectAutowireStrategy("true".equalsIgnoreCase(alwaysAutoWire));

        if (LOG.isInfoEnabled())
        {
            LOG.info("... initialized Struts-Spring integration successfully");
        }
    }
}

关 键一步就在于第26行，那句代码，只要使用自己的方法获得applicationContext对象就行了。而Spring对于 ApplicationContext对象也提供了多种实现，既然咱们想自己定义配置的名称和位置，那么咱们就使用 FileSystemXmlApplicationContext，嗯，这个类的使用就不用我赘述了。很简单，实例化的时候将配置的路径传入就ok了。最 后在struts的配置中，将我们自己实现的工厂类应用上去，如：

<constant name="struts.objectFactory" value="com.xk.commons.config.XKStrutsSpringObjectFactory" />

要 注意一点：代码71行中使用到了ClassReloadingXMLWebApplicationContext这个类，这个类的父类中会实现 FilesystemAlterationListener接口，这个接口在struts和spring提供的jar包中是找不到的，其包含在 apache的commons的jci库中，具体到jar包为commons-jci-fam-1.0.jar 下载地址：http://commons.apache.org/jci/downloads.html。

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