zookeeper 基本命令和java api
阿新 • • 發佈：2018-11-10
1.Zookeeper命令工具
啟動zookeeper服務後，連線到zookeeper服務：
zkServer -server localhost:2181
執行結果如下：
Connecting to localhost:2181
2018-06-10 03:52:52,540 [myid:] - INFO [main:[email protected]] - Client environment:zookeeper.version=3.4.10-39d3a4f269333c922ed3db283be479f9deacaa0f, built on 03/23/2017 10:13 GMT
2018-06-10 03:52:52,562 [myid:] - INFO [main: 控制檯會輸出一些配置資訊和“welcome to Zookeeper”，檢視zookeeper的相關操作，可以輸入 help 命令
[zk: localhost:2181(CONNECTED) 4] help
ZooKeeper -server host:port cmd args
stat path [watch]
set path data [version]
ls path [watch]
delquota [-n|-b] path
ls2 path [watch]
setAcl path acl
setquota -n|-b val path
history
redo cmdno
printwatches on|off
delete path [version]
sync path
listquota path
rmr path
get path [watch]
create [-s] [-e] path data acl
addauth scheme auth
quit
getAcl path
close
connect host:port
演示下常見的zookeeper基本操作
1.建立一個節點
節點的名字是zoo，節點的相關資訊是myData
[zk: localhost:2181(CONNECTED) 4] create /zoo myData
Created /zoo
再檢視下現在zookeeper包含的節點
[zk: localhost:2181(CONNECTED) 6] ls /
[zoo, zookeeper]
這時，可以看到zoo節點已經被建立
2.獲取指定節點的資訊
[zk: localhost:2181(CONNECTED) 7] get /zoo
myData
cZxid = 0x100000006
ctime = Sun Jun 10 10:35:55 PDT 2018
mZxid = 0x100000006
mtime = Sun Jun 10 10:35:55 PDT 2018
pZxid = 0x100000006
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 6
numChildren = 0
3.修改指定節點的資訊
[zk: localhost:2181(CONNECTED) 8] set /zoo animais
cZxid = 0x100000006
ctime = Sun Jun 10 10:35:55 PDT 2018
mZxid = 0x100000007
mtime = Sun Jun 10 10:39:06 PDT 2018
pZxid = 0x100000006
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0
再檢視修改後內容
[zk: localhost:2181(CONNECTED) 9] get /zoo
animais
cZxid = 0x100000006
ctime = Sun Jun 10 10:35:55 PDT 2018
mZxid = 0x100000007
mtime = Sun Jun 10 10:39:06 PDT 2018
pZxid = 0x100000006
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0
4.刪除節點
[zk: localhost:2181(CONNECTED) 12] delete /zoo
[zk: localhost:2181(CONNECTED) 13] ls /
[zookeeper]
結驗證，zoo節點已被刪除
2.java API的使用
首先需要在maven新增zookeeper的jar包
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.10</version>
</dependency>
具體程式碼如下：
public class ZookeeperDemo {
/** 服務地址，ip:port，多個地址用逗號隔開 */
private static final String SERVER_ADDRESS = "192.168.2.201:218,192.168.2.201:2182,192.168.2.201:2183";
/** 超時時間，毫秒為單位 */
private static final Integer TIMEOUT_MS = 3000;
/** 節點名 */
private static final String NODE_ZOO = "/zoo/mammal";
public static void main(String[] args) throws Exception {
ZooKeeper zk = new ZooKeeper(SERVER_ADDRESS, TIMEOUT_MS, new DemoWatcher());
waitUntilConnected(zk);
// 判斷節點是否存在
Stat stat = zk.exists(NODE_ZOO, false);
if (null == stat) {// 節點不存在
createNode(zk, NODE_ZOO, "i'm mammal", ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
} else {
getData(zk, NODE_ZOO, stat);
System.out.println(stat.getVersion());
updateNode(zk, NODE_ZOO, "i'm mammal haha", stat.getVersion());
}
}
/**
* 根據指定節點名字，建立節點
* @param zk zk客戶端
* @param node_zoo 節點名
* @param data 節點資訊
* @param ACL_LIST 訪問控制列表，這裡使用了完全開放的ACL，允許任何客戶端對znode進行讀寫
* @param createMode 建立znode的型別：有兩種型別的znode：短暫的和持久的。
* @throws KeeperException
* @throws InterruptedException
*/
public static void createNode(ZooKeeper zk, String node_zoo, String data,List<ACL> ACL_LIST,CreateMode createMode)
throws KeeperException, InterruptedException {
String createResult = zk.create(node_zoo, data.getBytes(), ACL_LIST ,createMode);
System.out.println(createResult);
}
/**
* 刪除節點
* @param zk zk客戶端
* @param node_zoo 節點名
* @param version 指定的版本，-1/無視版本
* @throws KeeperException
* @throws InterruptedException
*/
public static void deleteNode(ZooKeeper zk, String node_zoo, Integer version)
throws KeeperException, InterruptedException {
zk.delete(node_zoo, version);
}
/**
* 更新節點
* @param zk zk客戶端
* @param node_zoo 節點名
* @param data 節點資料
* @param version 指定的版本，-1/無視版本
* @throws KeeperException
* @throws InterruptedException
*/
public static void updateNode(ZooKeeper zk, String node_zoo, String data, Integer version)
throws KeeperException, InterruptedException {
zk.setData(node_zoo, data.getBytes(), version);
}
/**
* 根據節點名獲取節點資訊
* @param zk zk客戶端
* @param node_zoo 節點名
* @param stat 節點狀態
* @throws KeeperException
* @throws InterruptedException
*/
public static void getData(ZooKeeper zk, String node_zoo, Stat stat) throws KeeperException, InterruptedException {
byte[] bs = zk.getData(node_zoo, false, stat);
System.out.println(new String(bs));
}
/**
* 監聽類，接收來自zookeeper的回撥
* @author Administrator
*
*/
static class DemoWatcher implements Watcher {
public void process(WatchedEvent event) {
System.out.println("----------->");
System.out.println("path:" + event.getPath());
System.out.println("type:" + event.getType());
System.out.println("stat:" + event.getState());
System.out.println("<-----------");
}
}
/**
* 防止java程式未連上zookeeper的伺服器而往下執行，需等待zk的狀態碼
* @param zooKeeper
*/
public static void waitUntilConnected(ZooKeeper zooKeeper) {
CountDownLatch connectedLatch = new CountDownLatch(1);
Watcher watcher = new ConnectedWatcher(connectedLatch);
zooKeeper.register(watcher);
if (States.CONNECTING == zooKeeper.getState()) {
try {
connectedLatch.await();
} catch (InterruptedException e) {
throw new IllegalStateException(e);
}
}
}
static class ConnectedWatcher implements Watcher {
private CountDownLatch connectedLatch;
ConnectedWatcher(CountDownLatch connectedLatch) {
this.connectedLatch = connectedLatch;
}
public void process(WatchedEvent event) {
if (event.getState() == KeeperState.SyncConnected) {
connectedLatch.countDown();
}
}
}
}