没有 Spring Boot 的 Spring Cloud Config 客户端

Question

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。

Answer 1

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

的系统属性

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();
    }
}