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目录：
1. 对 zookeeper 节点进行增删改查既配置acl 权限等
2.使用 zookeeper 实现一个简易的配置中心
1. 对 zookeeper 节点进行增删改查既配置acl 权限等
apache 提供了对 zookeeper 操作的 api 操作。即引入对应的 jar 包即可进行操作zookeeper。‘
引入 apache zookeeper 的pom 配置。这里版本请保持与服务端版本一致，不然会有很多兼容性的问题
<dependency> <groupId>org.apache.zookeeper</groupId> <artifactId>zookeeper</artifactId> <version>3.5.8</version> </dependency>
将对 zookeeper 进行操作的 api 使用封装了一个测试类，包含：新增节点，修改节点，删除节点，查询节点，配置节点acl 权限等，可以在其中进行测试：
package com.example.demo.zookeeper; import lombok.extern.slf4j.Slf4j; import org.apache.zookeeper.*; import org.apache.zookeeper.data.ACL; import org.apache.zookeeper.data.Id; import org.apache.zookeeper.data.Stat; import org.apache.zookeeper.server.auth.DigestAuthenticationProvider; import org.junit.Before; import org.junit.Test; import java.io.IOException; import java.security.NoSuchAlgorithmException; import java.util.ArrayList; import java.util.List; import java.util.concurrent.CountDownLatch; @Slf4j public class ZookeeperClientTest { // ZooKeeper服务器列表，由英文逗号分开的host:port字符串组成， 每一个都代表一台ZooKeeper机器， // 也可以在connectString中设 置客户端连接上ZooKeeper 后的根目录，方法是在host:port字符串之后添加上这个根目录,实现隔离 private static final String ZK_ADDRESS="112.125.26.68:2181"; // 会话的超时时间，单位毫秒，在一个会话周期内，ZooKeeper客户端和服务器之间会通过心跳 检测机制来维持会话的有效性，‘ // 一旦在sessionTimeout时间内没有进行有效 的心跳检测，会话就会失效。 private static final int SESSION_TIMEOUT = 5000; private static ZooKeeper zooKeeper; private static final String ZK_NODE="/zk‐node"; @Before public void init() throws IOException, InterruptedException { final CountDownLatch countDownLatch=new CountDownLatch(1); // watchedEvent 为 Watcher事件通知处理器，该参 数可以设置为null 以表明不需要设置默认的 Watcher处理器 zooKeeper=new ZooKeeper(ZK_ADDRESS, SESSION_TIMEOUT,watchedEvent -> { if (watchedEvent.getState()== Watcher.Event.KeeperState.SyncConnected && watchedEvent.getType()== Watcher.Event.EventType.None){ countDownLatch.countDown(); log.info("连接成功！"); } }); log.info("连接中...."); countDownLatch.await(); } /** * 新增节点数据 * * @throws KeeperException * @throws InterruptedException */ @Test public void createTest() throws KeeperException, InterruptedException { String path = zooKeeper.create(ZK_NODE, "data".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT); log.info("created path: {}",path); } /** * 修改节点并删除指定版本节点 * @throws KeeperException * @throws InterruptedException */ @Test public void setTest() throws KeeperException, InterruptedException { Stat stat = new Stat(); byte[] data = zooKeeper.getData(ZK_NODE, false, stat); log.info("修改前: {}",new String(data)); zooKeeper.setData(ZK_NODE, "changed!".getBytes(), stat.getVersion()); // getData 可以查看节点的配置数据 byte[] dataAfter = zooKeeper.getData(ZK_NODE, false, stat); log.info("修改后: {}",new String(dataAfter)); // 删除指定版本的zookeeper节点 zooKeeper.delete(ZK_NODE,stat.getVersion()); } /** * 用 world 模式创建节点 * * @throws KeeperException * @throws InterruptedException */ @Test public void createWithAclTest1() throws KeeperException, InterruptedException { List<ACL> acLList = new ArrayList<ACL>(); ACL e = new ACL(); Id m_ = new Id(); m_.setId("anyone"); m_.setScheme("world"); int perms = ZooDefs.Perms.ADMIN | ZooDefs.Perms.READ; e.setId(m_); e.setPerms(perms); acLList.add(e); String s = getZooKeeper().create("/zk-node-1", "gj".getBytes(), acLList, CreateMode.PERSISTENT); log.info("create path: {}",s); } public static ZooKeeper getZooKeeper() { return zooKeeper; } /** * * 用授权模式创建节点 * @throws KeeperException * @throws InterruptedException */ @Test public void createWithAclTest2() throws KeeperException, InterruptedException { // 对连接添加授权信息 getZooKeeper().addAuthInfo("digest","u400:p400".getBytes()); List<ACL> acLList = new ArrayList<ACL>(); ACL e = new ACL(); Id m_ = new Id(); m_.setId("u400:p400"); m_.setScheme("auth"); int perms = ZooDefs.Perms.ADMIN | ZooDefs.Perms.READ; e.setId(m_); e.setPerms(perms); acLList.add(e); String s = getZooKeeper().create("/zk-node-2", "gj".getBytes(), acLList, CreateMode.PERSISTENT); log.info("create path: {}",s); } @Test public void createWithAclTest3() throws KeeperException, InterruptedException { // 对连接添加授权信息 getZooKeeper().addAuthInfo("digest","u400:p400".getBytes()); byte[] data = getZooKeeper().getData("/test", false, null); log.info("GET_DATA : {}",new String(data)); } }
2.使用 zookeeper 实现一个简易的配置中心
通过 watcher 监听节点配置的改动，并加载 zookeeper 指定节点的配置
package com.example.demo.zookeeper; import lombok.extern.slf4j.Slf4j; import org.apache.zookeeper.*; import org.apache.zookeeper.server.util.ConfigUtils; import java.io.IOException; import java.util.Scanner; import java.util.concurrent.CountDownLatch; /** * zookeeper 做配置中心 * */ @Slf4j public class ZookeeperConfigCenter { private final static String connectString = "112.125.26.68:2181,112.125.26.68:2182,112.125.26.68:2183,112.125.26.68:2184"; private static int SESSION_TIMEOUT=5* 1000; private static CountDownLatch countDownLatch=new CountDownLatch(1); private static ZooKeeper zookeeper =null; private static Watcher watcher = new Watcher() { @Override public void process(WatchedEvent event) { if (event.getType() == Event.EventType.None && event.getState() == Event.KeeperState.SyncConnected){ countDownLatch.countDown(); log.info(" 连接建立"); // start to watch config try { log.info(" 开始监听：{}",ZooDefs.CONFIG_NODE); zookeeper.getConfig(true,null); } catch (KeeperException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } }else if( event.getPath()!=null && event.getPath().equals(ZooDefs.CONFIG_NODE)){ try { byte[] config = zookeeper.getConfig(this, null); String clientConfigStr = ConfigUtils.getClientConfigStr(new String(config)); log.info(" 配置发生变更: {}",clientConfigStr); zookeeper.updateServerList(clientConfigStr.split(" ")[1]); } catch (KeeperException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } }; public static void main(String[] args) throws IOException, InterruptedException, KeeperException { zookeeper = new ZooKeeper(connectString, SESSION_TIMEOUT, watcher); countDownLatch.await(); Scanner scanner =new Scanner(System.in); while (true){ byte[] data = zookeeper.getData("/zookeeper/config", true, null); scanner.next(); log.info("DATA: {}",new String(data)); } } }
标签: zookeeper
