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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));
}
}
}