ZooKeeper for Java/Spring？

Question

是否有任何经过详细记录的Apache用例用于分发ZooKeeper应用程序的配置，特别是ZooKeeper服务？

与云服务的许多用户一样，我需要更改可变数量的Java服务的配置，最好是在运行时，而不需要重新启动服务。

更新

最后，我编写了一些东西，可以将ZooKeeper节点作为属性文件加载，并创建一个ResourcePropertySource并将其插入到Spring上下文中。请注意，这不会反映上下文启动后ZooKeeper节点中的更改。

public class ZooKeeperPropertiesApplicationContextInitializer implements ApplicationContextInitializer<ConfigurableApplicationContext> {
    private static final Logger logger = LoggerFactory.getLogger(ZooKeeperPropertiesApplicationContextInitializer.class);

    private final CuratorFramework curator;
    private String projectName;
    private String projectVersion;

    public ZooKeeperPropertiesApplicationContextInitializer() throws IOException {
        logger.trace("Attempting to construct CuratorFramework instance");

        RetryPolicy retryPolicy = new ExponentialBackoffRetry(10, 100);
        curator = CuratorFrameworkFactory.newClient("zookeeper", retryPolicy);
        curator.start();
    }

    /**
     * Add a primary property source to the application context, populated from
     * a pre-existing ZooKeeper node.
     */
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        logger.trace("Attempting to add ZooKeeper-derived properties to ApplicationContext PropertySources");

        try {
            populateProjectProperties();
            Properties properties = populatePropertiesFromZooKeeper();
            PropertiesPropertySource propertySource = new PropertiesPropertySource("zookeeper", properties);
            applicationContext.getEnvironment().getPropertySources().addFirst(propertySource);

            logger.debug("Added ZooKeeper-derived properties to ApplicationContext PropertySources");
            curator.close();
        } catch (IOException e) {
            logger.error("IO error attempting to load properties from ZooKeeper", e);
            throw new IllegalStateException("Could not load ZooKeeper configuration");
        } catch (Exception e) {
            logger.error("IO error attempting to load properties from ZooKeeper", e);
            throw new IllegalStateException("Could not load ZooKeeper configuration");
        } finally {
            if (curator != null && curator.isStarted()) {
                curator.close();
            }
        }
    }

    /**
     * Populate the Maven artifact name and version from a property file that
     * should be on the classpath, with values entered via Maven filtering.
     * 
     * There is a way of doing these with manifests, but it's a right faff when
     * creating shaded uber-jars.
     * 
     * @throws IOException
     */
    private void populateProjectProperties() throws IOException {
        logger.trace("Attempting to get project name and version from properties file");

        try {
            ResourcePropertySource projectProps = new ResourcePropertySource("project.properties");
            this.projectName = (String) projectProps.getProperty("project.name");
            this.projectVersion = (String) projectProps.getProperty("project.version");
        } catch (IOException e) {
            logger.error("IO error trying to find project name and version, in order to get properties from ZooKeeper");
        }
    }

    /**
     * Do the actual loading of properties.
     * 
     * @return
     * @throws Exception
     * @throws IOException
     */
    private Properties populatePropertiesFromZooKeeper() throws Exception, IOException {
        logger.debug("Attempting to get properties from ZooKeeper");

        try {
            byte[] bytes = curator.getData().forPath("/distributed-config/" + projectName + "/" + projectVersion);
            InputStream in = new ByteArrayInputStream(bytes);
            Properties properties = new Properties();
            properties.load(in);
            return properties;
        } catch (NoNodeException e) {
            logger.error("Could not load application configuration from ZooKeeper as no node existed for project [{}]:[{}]", projectName, projectVersion);
            throw e;
        }

    }

}

Answer 1

您应该考虑：

http://projects.spring.io/spring-cloud/

git存储库支持的

Spring集中外部配置管理。配置资源直接映射到Spring Environment，但如果需要的话，非Spring应用程序可以使用它。

可在此获得源代码：

https://github.com/spring-cloud/spring-cloud-config

示例应用程序如下：

https://github.com/spring-cloud/spring-cloud-config/blob/master/spring-cloud-config-sample/src/main/java/sample/Application.java

Answer 2

我在propertyplaceholderconfigurer中创建了一组spring集成动物园管理员和spring框架，在github：https://github.com/james-wu-shanghai/spring-zookeeper.git中您可以查看一下。

Answer 3

特别是spring，但是对于java来说，有一个分布式OSGI标准的CXF实现，它使用ZooKeeper作为发现服务器，将更新的包向下推到容器：http://cxf.apache.org/dosgi-discovery.html。