Zookeeper 配置中心服务治理实现

墨蓝 2022-05-16 05:09 216阅读 0赞

## Zookeeper配置中心服务治理实现 ##

### 背景 ###

上一篇博客详细讲解了为什么我们要选择Zookeeper作为服务发现框架而不是使用Eureka。  
[参考][Link 1] 这篇博客将继续讲解怎么实现的，里面会有大量的代码的拷贝，具体的架构可以参考上一篇博客的架构演进图。本篇主要讲解实现过程。

### 准备工作 ###

1.  Spring Maven项目添加Zookeeper的依赖包,这样就可以使用Zookeeper的SDK了。

<dependency>
                <groupId>org.apache.zookeeper</groupId>
                <artifactId>zookeeper</artifactId>
                <version>3.3.6</version>
           </dependency>

### football-server实现服务注册功能 ###

创建Zookeeper.properties在resources目录下，并写入参数。

server.parent.name = football (注册服务的父路径)
    server.instance.name = football-server (注册服务的名字)
    server.port = 8081 (注册服务的端口号)
    zookeeper.host = Your zookeeper address
    zookeeper.port = Your zookeeper port

创建Zookeeper.properties读取文件的类。

@Component
    public class ZookeeperProperties { 
    
        @Value("${zookeeper.host}")
        private String host;
    
        @Value("${zookeeper.port}")
        private String zkPort;
    
        @Value("${server.parent.name}")
        private String parentName;
    
        @Value("${server.port}")
        private String serverPort;
    
        @Value("${server.instance.name}")
        private String instanceName;
    
        public String getZookeeperAddress(){
    
            return String.format("%s:%s",host,zkPort);
        }
    
        public String getParentName() {
            parentName=parentName.replace("/","");
            return parentName;
        }
    
        public String getServerPort() {
            return serverPort;
        }
    
        public String getInstanceName() {
            parentName=parentName.replace("/","");
            return instanceName;
        }
    }

在服务启动成功后，调用Zookeeper的JavaSDK向Zookeeper注册自己。

@Service
    public class ZookeeperRegistrar implements ApplicationListener<ContextRefreshedEvent> {
    
    
        @Autowired
        ZookeeperProperties zookeeperProperties;
    
    
    
        private static Logger log = LoggerFactory.getLogger(ZookeeperRegistrar.class);
    
    
        @Override
        public void onApplicationEvent(ContextRefreshedEvent contextRefreshedEvent) {
            if(contextRefreshedEvent.getApplicationContext().getParent()==null){
                try {
                    registry();
                } catch (IOException e) {
                    log.error("fooball-server registry to zookeeper fault ,{}",e.getMessage());
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    log.error("fooball-server registry to zookeeper fault ,{}",e.getMessage());
                    e.printStackTrace();
                } catch (KeeperException e) {
                    log.error("fooball-server registry to zookeeper fault ,{}",e.getMessage());
                    e.printStackTrace();
                }
    
            }
        }
    
        public void registry() throws IOException, KeeperException, InterruptedException {
    
            Watcher watcher=new Watcher() {
                @Override
                public void process(WatchedEvent watchedEvent) {
                    log.info("zookeeper watcher ,{}",watchedEvent.toString());
                }
            };
            ZooKeeper zooKeeper = new ZooKeeper(zookeeperProperties.getZookeeperAddress(),200000,watcher);
            initParentPath(zooKeeper,watcher);
            createInstancePath(zooKeeper,watcher);
    
        }
    
        public void initParentPath(ZooKeeper zookeeper,Watcher watcher) throws KeeperException, InterruptedException, UnknownHostException {
            String parentPath = String.format("/%s",zookeeperProperties.getParentName());
            log.info("fooball-server parentPath:{}",parentPath);
            if(zookeeper.exists(parentPath,watcher)==null){
                zookeeper.create(parentPath,null,ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
                log.info("create parentPath {} success.",parentPath);
            }
    
        }
    
        public void createInstancePath(ZooKeeper zooKeeper,Watcher watcher) throws KeeperException, InterruptedException, UnknownHostException {
            String instancePath = String.format("/%s/%s",zookeeperProperties.getParentName(),zookeeperProperties.getInstanceName());
            zooKeeper.create(instancePath,instanceInfoToByte(),ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
            log.info("create path {} success.",zookeeperProperties.getInstanceName());
        }
    
    
        public String getHost() throws UnknownHostException {
            InetAddress address = InetAddress.getLocalHost();
            return address.getHostAddress();
        }
    
        public InstanceInfo createInstanceInfo() throws UnknownHostException {
            String host = String.format("%s:%s",getHost(),zookeeperProperties.getServerPort());
            log.info("current instance host {}",host);
            return new InstanceInfo(zookeeperProperties.getInstanceName(),host);
        }
    
        public byte[] instanceInfoToByte() throws UnknownHostException {
            Gson gson=new Gson();
            InstanceInfo instanceInfo = createInstanceInfo();
            return gson.toJson(instanceInfo).getBytes();
        }
    
    
    
    }

### fooball-meta实现服务发现功能 ###

创建Zookeeper.properties和创建读取.properties文件的类和football-server一致。

从Zookeeper获取注册服务的参数

@Service
    public class MetaService implements IMetaService { 
    
        @Autowired
        ZooKeeper zooKeeper;
    
        @Autowired
        ZookeeperProperties zookeeperProperties;
    
        @Autowired
        Watcher watcher;
    
        private static Logger log = LoggerFactory.getLogger(MetaService.class);
    
        @Override
        public List<InstanceInfo> getServiceInfo() {
            try {
                String parentPath = String.format("/%s",zookeeperProperties.getParentName());
                List<String> childs = zooKeeper.getChildren(parentPath,false);
                return getInstancesByName(childs);
            } catch (KeeperException e) {
                log.error("Zookeeper getChildren error!");
                e.printStackTrace();
            } catch (InterruptedException e) {
                log.error("Zookeeper getChildren error!");
                e.printStackTrace();
            }
            return Collections.emptyList();
        }
    
        public List<InstanceInfo> getInstancesByName(List<String> childs) throws KeeperException, InterruptedException {
            List<InstanceInfo> instanceInfos =new ArrayList<InstanceInfo>();
            for(String childName:childs){
                String childPath = String.format("/%s/%s",zookeeperProperties.getParentName(),childName);
                instanceInfos.add(getInstanceFromZK(childPath));
            }
            return instanceInfos;
        }
    
        public InstanceInfo getInstanceFromZK(String path) throws KeeperException, InterruptedException {
    
            byte[] data = zooKeeper.getData(path,watcher,null);
            String instanceJson = new String(data);
            return new Gson().fromJson(instanceJson,InstanceInfo.class);
        }
    
    }

[Link 1]: https://blog.csdn.net/qq_24210767/article/details/81713075