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小編給大家分享一下springboot使用zookeeper(curator)實現注冊發現與負載均衡的方法，相信大部分人都還不怎么了解，因此分享這篇文章給大家參考一下，希望大家閱讀完這篇文章后大有收獲，下面讓我們一起去了解一下吧！
最簡單的實現服務高可用的方法就是集群化，也就是分布式部署，但是分布式部署會帶來一些問題。比如：
1、各個實例之間的協同(鎖)
2、負載均衡
3、熱刪除
這里通過一個簡單的實例來說明如何解決注冊發現和負載均衡。
1、先解決依賴，這里只給出zk相關的依賴，pom.xml如下
org.apache.zookeeper zookeeper 3.4.8 org.apache.curator curator-recipes 2.9.1 org.apache.curator curator-client 2.9.1
2、ZkClient
這里使用的是curator，curator是對zookeeper的簡單封裝，提供了一些集成的方法，或者是提供了更優雅的api，舉例來說
zk的create(path, mode, acl, data)方法 == curator create().withMode(mode).forPath(path)調用鏈
package com.dqa.prometheus.client.zookeeper;import org.apache.curator.RetryPolicy;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.CuratorFrameworkFactory;import org.apache.curator.retry.ExponentialBackoffRetry;import org.apache.zookeeper.CreateMode;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.net.InetAddress;import java.util.ArrayList;import java.util.List;public class ZkClient { private final Logger logger = LoggerFactory.getLogger(this.getClass()); private CuratorFramework client; private String zookeeperServer; private int sessionTimeoutMs; private int connectionTimeoutMs; private int baseSleepTimeMs; private int maxRetries; public void setZookeeperServer(String zookeeperServer) { this.zookeeperServer = zookeeperServer;
} public String getZookeeperServer() { return zookeeperServer;
} public void setSessionTimeoutMs(int sessionTimeoutMs) { this.sessionTimeoutMs = sessionTimeoutMs;
} public int getSessionTimeoutMs() { return sessionTimeoutMs;
} public void setConnectionTimeoutMs(int connectionTimeoutMs) { this.connectionTimeoutMs = connectionTimeoutMs;
} public int getConnectionTimeoutMs() { return connectionTimeoutMs;
} public void setBaseSleepTimeMs(int baseSleepTimeMs) { this.baseSleepTimeMs = baseSleepTimeMs;
} public int getBaseSleepTimeMs() { return baseSleepTimeMs;
} public void setMaxRetries(int maxRetries) { this.maxRetries = maxRetries;
} public int getMaxRetries() { return maxRetries;
} public void init() {
RetryPolicy retryPolicy = new ExponentialBackoffRetry(baseSleepTimeMs, maxRetries);
client = CuratorFrameworkFactory.builder().connectString(zookeeperServer).retryPolicy(retryPolicy)
.sessionTimeoutMs(sessionTimeoutMs).connectionTimeoutMs(connectionTimeoutMs).build();
client.start();
} public void stop() {
client.close();
} public CuratorFramework getClient() { return client;
} public void register() { try {
String rootPath = "/" + "services";
String hostAddress = InetAddress.getLocalHost().getHostAddress();
String serviceInstance = "prometheus" + "-" + hostAddress + "-";
client.create().creatingParentsIfNeeded().withMode(CreateMode.EPHEMERAL_SEQUENTIAL).forPath(rootPath + "/" + serviceInstance);
} catch (Exception e) {
logger.error("注冊出錯", e);
}
} public List getChildren(String path) {
List childrenList = new ArrayList<>(); try {
childrenList = client.getChildren().forPath(path);
} catch (Exception e) {
logger.error("獲取子節點出錯", e);
} return childrenList;
} public int getChildrenCount(String path) { return getChildren(path).size();
} public List getInstances() { return getChildren("/services");
} public int getInstancesCount() { return getInstances().size();
}
} 2、configuration如下
package com.dqa.prometheus.configuration;import com.dqa.prometheus.client.zookeeper.ZkClient;import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;
@Configurationpublic class ZkConfiguration {
@Value("${zookeeper.server}") private String zookeeperServer;
@Value(("${zookeeper.sessionTimeoutMs}")) private int sessionTimeoutMs;
@Value("${zookeeper.connectionTimeoutMs}") private int connectionTimeoutMs;
@Value("${zookeeper.maxRetries}") private int maxRetries;
@Value("${zookeeper.baseSleepTimeMs}") private int baseSleepTimeMs;
@Bean(initMethod = "init", destroyMethod = "stop") public ZkClient zkClient() {
ZkClient zkClient = new ZkClient();
zkClient.setZookeeperServer(zookeeperServer);
zkClient.setSessionTimeoutMs(sessionTimeoutMs);
zkClient.setConnectionTimeoutMs(connectionTimeoutMs);
zkClient.setMaxRetries(maxRetries);
zkClient.setBaseSleepTimeMs(baseSleepTimeMs); return zkClient;
}
}配置文件如下
#============== zookeeper ===================
zookeeper.server=10.93.21.21:2181,10.93.18.34:2181,10.93.18.35:2181
zookeeper.sessionTimeoutMs=6000
zookeeper.connectionTimeoutMs=6000
zookeeper.maxRetries=3
zookeeper.baseSleepTimeMs=10003、注冊發現
是通過上面封裝的ZkClient中的register方法實現的，調用如下。
package com.dqa.prometheus;
import com.dqa.prometheus.client.zookeeper.ZkClient;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.orm.jpa.EntityScan;
import org.springframework.context.ApplicationContext;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.EnableScheduling;
@SpringBootApplication
@EnableAsync
@EnableScheduling
@EntityScan(basePackages="com.xiaoju.dqa.prometheus.model")
public class Application {
public static void main(String[] args) {
ApplicationContext context = SpringApplication.run(Application.class, args);
ZkClient zkClient = context.getBean(ZkClient.class);
zkClient.register();
}
}注冊代碼說明：
public void register() { try {
String rootPath = "/" + "services";
String hostAddress = InetAddress.getLocalHost().getHostAddress();
String serviceInstance = "prometheus" + "-" + hostAddress + "-";
client.create().creatingParentsIfNeeded().withMode(CreateMode.EPHEMERAL_SEQUENTIAL).forPath(rootPath + "/" + serviceInstance);
} catch (Exception e) {
logger.error("注冊出錯", e);
}
}1、zk中的注冊路徑
/services/prometheus-10.93.21.21-00000000001
2、CreateMode有四種，選擇EPHEMERAL_SEQUENTIAL的原因是，服務關閉的時候session超時，zk節點會自動刪除，同時自增id可以實現鎖和負載均衡，下面再說
1、PERSISTENT 持久化目錄節點，存儲的數據不會丟失。2、PERSISTENT_SEQUENTIAL 順序自動編號的持久化目錄節點，存儲的數據不會丟失，并且根據當前已近存在的節點數自動加 1，然后返回給客戶端已經成功創建的目錄節點名。3、EPHEMERAL 臨時目錄節點，一旦創建這個節點的客戶端與服務器端口也就是session 超時，這種節點會被自動刪除。 4、EPHEMERAL_SEQUENTIAL 臨時自動編號節點，一旦創建這個節點的客戶端與服務器端口也就是session 超時，這種節點會被自動刪除，并且根據當前已近存在的節點數自動加 1，然后返回給客戶端已經成功創建的目錄節點名。
4、負載均衡
/*
* 我是第幾個實例, 做負載均衡
* */
List instanceList = zkClient.getInstances();
Collections.sort(instanceList);
String hostAddress = NetFunction.getAddressHost(); int instanceNo = 0; if (hostAddress != null) { for (int i=0; i waitingTasks = checkTaskDao.getTasks(taskType, TaskStatus.WAITING.getValue());
Iterator waitingIterator = waitingTasks.iterator(); while (waitingIterator.hasNext()) { if (waitingIterator.next().getTaskId().hashCode() % instanceCount != instanceNo) {
waitingIterator.remove();
}
} 說明：
1、例如有3個實例(zkClient.getInstances())，那么通過IP我們把3個實例按照自增id排序分別標號為0，1，2
2、對第一個實例也就是instanceNo=0，只執行taskId.hashCode() % 3 == 0的任務，其他兩個實例類似
3、當有一個實例掛掉，2個實例，instanceNo=0只執行taskId.hashCode() % 2 == 0的任務，實現熱刪除
以上是springboot使用zookeeper(curator)實現注冊發現與負載均衡的方法的所有內容，感謝各位的閱讀！相信大家都有了一定的了解，希望分享的內容對大家有所幫助，如果還想學習更多知識，歡迎關注億速云行業資訊頻道！
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