我们有一个现有的 Spring Web 应用程序作为 WAR 文件部署到 Amazon Elastic Beanstalk 中。目前，我们将属性文件加载为 http 资源，以便为我们提供属性占位符配置解析的单一来源。我正在研究用新的 spring 云配置服务器替换它，以便为我们提供 git 版本控制等的好处。

然而文档(http://cloud.spring.io/spring-cloud-config/spring-cloud-config.html)似乎只描述了一个 Spring Boot 客户端应用程序。是否可以在现有 Web 应用程序中设置 Spring Cloud Config Client？我是否需要手动设置 Bootstrap 父应用程序上下文等 - 有没有这样的例子？我们当前的 spring 配置是基于 XML 的。

最佳答案

引用:https://wenku.baidu.com/view/493cf9eba300a6c30d229f49.html

Root WebApplicationContext 和 Servlet WebApplicationContext 使用 Environment 并根据 spring 配置文件初始化 PropertySources。对于非 Spring Boot 应用程序，我们需要自定义这些以从 Config Server 获取属性，并在属性更改时刷新 bean。以下是使配置在 SpringMVC 中工作所需的更改。您还需要 spring.profile.active

1. 创建一个 CustomBeanFactoryPostProcessor 并将所有 bean 定义上的 lazyInit 设置为 true 以延迟初始化所有 bean，即仅在请求时初始化 bean。

   @Component
   public class AddRefreshScopeProcessor implements BeanFactoryPostProcessor, ApplicationContextAware {
   
   private static ApplicationContext applicationContext;
   
   @SuppressWarnings("unchecked")
   @Override
   public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
   
       String[] beanNames = applicationContext.getBeanDefinitionNames();
       for(int i=0; i<beanNames.length; i++){
           BeanDefinition beanDef = beanFactory.getBeanDefinition(beanNames[i]);
           beanDef.setLazyInit(true);
           beanDef.setScope("refresh");
       }
   }
   
   @Override
   public void setApplicationContext(ApplicationContext context)
           throws BeansException {
       applicationContext = context;
   }
   
   /**
    * Get a Spring bean by type.
    * 
    * @param beanClass
    * @return
    */
   public static <T> T getBean(Class<T> beanClass) {
       return applicationContext.getBean(beanClass);
   }
   
   /**
    * Get a Spring bean by name.
    * 
    * @param beanName
    * @return
    */
   public static Object getBean(String beanName) {
       return applicationContext.getBean(beanName);
     }
   }
   

2. 创建一个自定义类，扩展 StandardServletEnvironment 并覆盖 initPropertySources 方法以加载其他 PropertySources(来自配置服务器)。

    public class CloudEnvironment extends StandardServletEnvironment {
   
     @Override
       public void initPropertySources(ServletContext servletContext, ServletConfig servletConfig) {
    super.initPropertySources(servletContext,servletConfig);
    customizePropertySources(this.getPropertySources());
      }
   
   @Override
     protected void customizePropertySources(MutablePropertySources propertySources) {
       super.customizePropertySources(propertySources);
       try {
         PropertySource<?> source = initConfigServicePropertySourceLocator(this);
         propertySources.addLast(source);
   
       } catch (
   
       Exception ex) {
         ex.printStackTrace();
       }
     }
   
     private PropertySource<?> initConfigServicePropertySourceLocator(Environment environment) {
   
       ConfigClientProperties configClientProperties = new ConfigClientProperties(environment);
       configClientProperties.setUri("http://localhost:8888");
       configClientProperties.setProfile("dev");
       configClientProperties.setLabel("master");
       configClientProperties.setName("YourApplicationName");
   
       System.out.println("##################### will load the client configuration");
       System.out.println(configClientProperties);
   
       ConfigServicePropertySourceLocator configServicePropertySourceLocator =
           new ConfigServicePropertySourceLocator(configClientProperties);
   
       return configServicePropertySourceLocator.locate(environment);
       }
   
     }
   

3. 创建一个自定义的ApplicatonContextInitializer并重写initialize方法来设置custom Enviroment而不是StandardServletEnvironment.

   public class ConfigAppContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
   
   @Override
   public void initialize(ConfigurableApplicationContext applicationContext) {
       applicationContext.setEnvironment(new CloudEnvironment());
     }
   }
   

4. 修改 web.xml 以将此自定义上下文初始化程序用于 application context 和 servlet context。

   <servlet>
       <servlet-name>dispatcher</servlet-name>
           <servlet-class>
               org.springframework.web.servlet.DispatcherServlet
           </servlet-class>
       <init-param>
           <param-name>contextInitializerClasses</param-name>
           <param-value>com.my.context.ConfigAppContextInitializer</param-value>
       </init-param>
       <load-on-startup>1</load-on-startup>
   </servlet>
   
   
   <servlet-mapping>
       <servlet-name>dispatcher</servlet-name>
       <url-pattern>/</url-pattern>
   </servlet-mapping>
   
   <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
   </listener>
   
   <context-param>
       <param-name>contextInitializerClasses</param-name>
       <param-value>com.my.context.ConfigAppContextInitializer</param-value>
   </context-param>
   
   <context-param>
       <param-name>contextConfigLocation</param-name>
       <param-value>/WEB-INF/dispatcher-servlet.xml</param-value>
   </context-param>
   

5. 要刷新创建了刷新端点的 bean，您还需要刷新 应用程序上下文。

   @Controller
   public class RefreshController {
   
   @Autowired
   private RefreshAppplicationContext refreshAppplicationContext;
   
   @Autowired
   private RefreshScope refreshScope;
   
   @RequestMapping(path = "/refreshall", method = RequestMethod.GET)
   public String refresh() {
       refreshScope.refreshAll();
       refreshAppplicationContext.refreshctx();
       return "Refreshed";
   }
   }
   

RefreshAppplicationContext.java

@Component
public class RefreshAppplicationContext implements ApplicationContextAware {

    private ApplicationContext applicationContext;
    public void setApplicationContext(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
    }


    public void refreshctx(){
        ((XmlWebApplicationContext)(applicationContext)).refresh();
    }
}

关于没有 Spring Boot 的 Spring Cloud Config 客户端，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28367425/