跟小弟我StepByStep学FLEX教程-Demo12之FLEX和Spring整合

跟我StepByStep学FLEX教程------FLEX和Spring整合 

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      这一讲是基于DEMO11，所以没有看DEMO11的读者请一定阅读，因为Spring的整合是基于J2EE的。

      因为要和Spring整合，所以先简单讲一下Spring（如果要对Spring没有接触过的读者也没关系，按照讲的内容也能做，但是这样没啥实际意义，所以要对本讲要有所收获，必须对Spring有一定的理解）。

      首先下载Spring，作者选择的Spring版本Spring Framework2.0.8。可以在官网

http://www.springsource.org/下载，也可以去网络搜索都可以。

      Spring对于J2EE来说，读者应该都非常熟悉，Spring以其轻量级的应用迅速的普及。

      对于Spring都需要了解的两个重要概念：

      1、控制反转（IoC=Inversion of  Control），依赖注入（DI=Dependency Injection）；

           通俗一点来讲，比如作者在工作中经常使用的硬件设备：Dell620笔记本电脑、USB活动硬盘、aigo移动U盘。大家很熟悉吧。

           这三个设备都支持USB接口。需要将数据复制到外边的存储设备时，根据实际情况决定保存在U盘还是活动硬盘。

           相信这种操作大家司空见惯，而这也正是所谓依赖注入的一个典型例子。

           笔记本电脑和外围存储通过笔记本的USB接口相连，对于笔记本而言，只是将用户指定数据发送到USB接口，而这些数据何去何从，则由当前的USB设备决定。

      2、面向切面编程（AOP=Aspect Oriented Programming）；

           这个大家可能觉得很抽象，其实现在大家应该都接触过，作者举两个例子：一个是WebWork框架的Intecepor就是AOP的应用；再一个大家更熟悉了，J2EE系统的Log4j的日志系统对于读者做的系统来说就是一个AOP。

           切面切面，就是一个截面，所做的程序不对现有系统进行破坏，但是随时可以打开关闭，这么理解就是很通俗通俗的理解了。

      这儿就简单提及一下，因为主要还是讲Flex和Spring的整合，读者就一步一步来做吧：）

            呵呵，大家觉得Spring的概念容易理解了吧：）

      Flex和Spring的整合：

      1、将Spring的jar包拷贝到WEB-INF的lib下；（这个是必须的，否则怎么整合Spring）

      2、在web.xml中注册Spring，如下配置：

<!-- Spring configuration file (Not needed if you don't use Spring) -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext.xml</param-value>
    </context-param>

<!-- Spring ContextLoaderListener (Not needed if you don't use Spring) -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

     3、增加SpringFactory.java，代码如下：

package com.samples.factories;

import org.springframework.context.ApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;

import flex.messaging.FactoryInstance;
import flex.messaging.FlexFactory;
import flex.messaging.config.ConfigMap;
import flex.messaging.services.ServiceException;

/**
 * This interface is implemented by factory components which provide
 * instances to the flex messaging framework.  To configure flex data services
 * to use this factory, add the following lines to your services-config.xml
 * file (located in the WEB-INF/flex directory of your web application).
 *
 * &lt;factories&gt;
 *     &lt;factory id="spring" class="flex.samples.factories.SpringFactory" /&gt;
 *  &lt;/factories&gt;
 *
 * You also must configure the web application to use spring and must copy the spring.jar
 * file into your WEB-INF/lib directory.  To configure your app server to use spring,
 * you add the following lines to your WEB-INF/web.xml file:
 *
 *   &lt;context-param&gt;
 *        &lt;param-name&gt;contextConfigLocation&lt;/param-name&gt;
 *        &lt;param-value&gt;/WEB-INF/applicationContext.xml&lt;/param-value&gt;
 *   &lt;/context-param&gt;
 *
 *   &lt;listener&gt;
 *       &lt;listener-class&gt;org.springframework.web.context.ContextLoaderListener&lt;/listener-class&gt;
 *   &lt;/listener&gt;
 *
 * Then you put your spring bean configuration in WEB-INF/applicationContext.xml (as per the
 * line above).  For example:
 *
 *  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
 *  &lt;!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"&gt;
 *  
 *  &lt;beans&gt;
 *    &lt;bean name="weatherBean" class="dev.weather.WeatherService" singleton="true"/&gt;
 *  &lt;/beans&gt;
 * 
 * Now you are ready to define a destination in flex that maps to this existing service.
 * To do this you'd add this to your WEB-INF/flex/remoting-config.xml:
 *
 *  &lt;destination id="WeatherService"&gt;
 *      &lt;properties&gt;
 *          &lt;factory&gt;spring&lt;/factory&gt;
 *          &lt;source&gt;weatherBean&lt;/source&gt;
 *      &lt;/properties&gt;
 *  &lt;/destination&gt;
 *
 * @author Jeff Vroom
 */
public class SpringFactory implements FlexFactory
{
    private static final String SOURCE = "source";

    /**
     * This method can be used to initialize the factory itself.  It is called with configuration
     * parameters from the factory tag which defines the id of the factory. 
     */
    public void initialize(String id, ConfigMap configMap) {}

    /**
     * This method is called when we initialize the definition of an instance
     * which will be looked up by this factory.  It should validate that
     * the properties supplied are valid to define an instance.
     * Any valid properties used for this configuration must be accessed to
     * avoid warnings about unused configuration elements.  If your factory
     * is only used for application scoped components, this method can simply
     * return a factory instance which delegates the creation of the component
     * to the FactoryInstance's lookup method.
     */
    public FactoryInstance createFactoryInstance(String id, ConfigMap properties)
    {
        SpringFactoryInstance instance = new SpringFactoryInstance(this, id, properties);
        instance.setSource(properties.getPropertyAsString(SOURCE, instance.getId()));
        System.out.println("SpringSpringSpring" + instance.toString());
        return instance;
    } // end method createFactoryInstance()

    /**
     * Returns the instance specified by the source
     * and properties arguments.  For the factory, this may mean
     * constructing a new instance, optionally registering it in some other
     * name space such as the session or JNDI, and then returning it
     * or it may mean creating a new instance and returning it.
     * This method is called for each request to operate on the
     * given item by the system so it should be relatively efficient.
     * <p>
     * If your factory does not support the scope property, it
     * report an error if scope is supplied in the properties
     * for this instance.
     */
    public Object lookup(FactoryInstance inst)
    {
        SpringFactoryInstance factoryInstance = (SpringFactoryInstance) inst;
        return factoryInstance.lookup();
    }

    static class SpringFactoryInstance extends FactoryInstance
    {
        SpringFactoryInstance(SpringFactory factory, String id, ConfigMap properties)
        {
            super(factory, id, properties);
        }

        public String toString()
        {
            return "SpringFactory instance for id=" + getId() + " source=" + getSource() + " scope=" + getScope();
        }

        public Object lookup()
        {
            ApplicationContext appContext = WebApplicationContextUtils.getWebApplicationContext(flex.messaging.FlexContext.getServletConfig().getServletContext());
            String beanName = getSource();

            try
            {
                return appContext.getBean(beanName);
            }
            catch (NoSuchBeanDefinitionException nexc)
            {
                ServiceException e = new ServiceException();
                String msg = "Spring service named '" + beanName + "' does not exist.";
                e.setMessage(msg);
                e.setRootCause(nexc);
                e.setDetails(msg);
                e.setCode("Server.Processing");
                throw e;
            }
            catch (BeansException bexc)
            {
                ServiceException e = new ServiceException();
                String msg = "Unable to create Spring service named '" + beanName + "' ";
                e.setMessage(msg);
                e.setRootCause(bexc);
                e.setDetails(msg);
                e.setCode("Server.Processing");
                throw e;
            }
        }
       
    }

}

     4、在services-config.xml中注册SpringFacotry，配置如下：

<factories>
     <factory id="spring" class="com.samples.factories.SpringFactory"/>
    </factories>

     5、接下来就要在applicationContext.mxl中注册helloJavaFlexBean，配置如下:

<bean id="helloJavaFlexBean" class="com.test.HelloJavaFlex">
    </bean>

     6、在remoting-config.xml中将SpringBean公开给Flex客户端，配置如下：

<destination id="helloJavaFlex"> 
    <properties>
      <factory>spring</factory>
      <source>helloJavaFlexBean</source>
     </properties>
    </destination>

     其它的代码都不用改动，运行一下，和Demo11的运行效果一样。

     读者可能会有疑问，增加了这么多配置，效果还和Demo11一样？

     1、这样的整合对于这种演示的小程序来说确实意义不大，但是大型项目这种Spring方式优点就非常明显了，因为和Flex客户端公开的是SpringBean的声明，所以无论底层逻辑甚至文件名称得改动，都不会有什么影响；

     2、Spring整合进来，就可以使用Spring很多特性了，呵呵，下个DEMO就会使用Spring的自带JDBCTemplate访问数据库；

     3、Spring的整合，对于Hibernate的整合提供了更大的便捷，这个也会在后边的DEMO中提及。

     下一讲对这这讲的Demo做个简单的解释。

12 楼 catlovefox 2010-04-22  

要添加的Spring的包给我们列出来吗？

domsn 写道

楼主，你好，我更想知道，你是怎么知道这些的，方便的话，发到我邮箱行么，domsn.lee@foxmail.com

这问题，真好玩~