源码时代java干货分享|带你认识zookeeper分布式服务框架

<parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>2.0.5.RELEASE</version>

</parent>

​

<dependencies>

    <dependency>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-web</artifactId>

    </dependency>

​

    <dependency>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-configuration-processor</artifactId>

        <optional>true</optional>

    </dependency>

​

    <dependency>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-test</artifactId>

    </dependency>

​

    <dependency>

        <groupId>junit</groupId>

        <artifactId>junit</artifactId>

        <version>4.12</version>

    </dependency>

    <dependency>

        <groupId>org.apache.curator</groupId>

        <artifactId>curator-recipes</artifactId>

        <version>4.0.0</version>

    </dependency>

</dependencies>

​

<properties>

    <java.version>1.8</java.version>

</properties>

config.zookeeper.url=127.0.0.1:2181
config.zookeeper.nodename=pay-server-config

@Configuration
public class ZkConfig

    @Value("$config.zookeeper.url")
    String zkUrl;   // 配置文件读取zk的地址
    @Value("$config.zookeeper.nodename")
    String nodename;  // 配置所在的节点名

    private Properties properties = new Properties();

    public String getProperty(String key)
        String value = properties.getProperty(key);

        if (StringUtils.isEmpty(value))
            throw new RuntimeException("配置信息不存在");
        
        return value;
    

    @PostConstruct
    public void init()
        CuratorFramework zkclient = CuratorFrameworkFactory.newClient(zkUrl,
                new RetryOneTime(1000));
        zkclient.start();// 启动Zookeeper的连接

        try 
            // 1. 读取zookeeper数据
            HashMap<String, String> configMap = new HashMap<>();
            List<String> configKeys = zkclient.getChildren().forPath("/" + nodename);
            for (String configKey : configKeys)
                byte[] data = zkclient.getData().forPath("/" + nodename + "/" + configKey);
                configMap.put(configKey, new String(data));
            

            // 2. 把数据存储到 properties中
            properties.putAll(configMap);

            // 3. 配置发生修改  -->  watch监听机制
            TreeCache treeCache = new TreeCache(zkclient, "/" + nodename);
            treeCache.start(); // 监听整个节点内的数据变化

            treeCache.getListenable().addListener(new TreeCacheListener()
                @Override
                public void childEvent(CuratorFramework curatorFramework,

• • •    TreeCacheEvent treeCacheEvent) throws Exception 
                         // 如果zk中有数据变化，执行相应的代码
                         switch (treeCacheEvent.getType())
                             case NODE_UPDATED:
                             System.out.println("数据发生了变化: "+treeCacheEvent.getData());
      
                             String key = treeCacheEvent.getData().getPath().replace("/"+nodename+"/","");
                             String value = new String(treeCacheEvent.getData().getData());
                             properties.setProperty(key, value);
                               break;
                             default:
                               break;// 其他情况不做处理
    •        
                       
                   );
                 catch (Exception e)
                    e.printStackTrace();