ZooKeeper：zookeeper的常用命令（节点的新增、更新、删除）

1、新增节点

（1）先启动ZooKeeper，再登录到ZooKeeper

[root@zhai bin]# ./zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/zookeeper/zookeeper-3.4.10/bin/../conf/zoo.cfg
Starting zookeeper ... already running as process 2183.
[root@zhai bin]# ./zkCli.sh
Connecting to localhost:2181

（2）创建持久化节点并写入数据

[zk: localhost:2181(CONNECTED) 1] create /hadoop "nihao2020"
Created /hadoop
[zk: localhost:2181(CONNECTED) 2] 

根据结点路径读取数据

[zk: localhost:2181(CONNECTED) 2] get /hadoop
nihao2020
cZxid = 0x4
ctime = Thu Oct 22 04:02:38 CST 2020
mZxid = 0x4
mtime = Thu Oct 22 04:02:38 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 9
numChildren = 0
[zk: localhost:2181(CONNECTED) 3] 

输入quit命令退出后重新登录依旧能够读取到数据，说明数据是持久化存储的

（3）创建临时结点并写入数据

[zk: localhost:2181(CONNECTED) 1] create -e /test "a"
Created /test
[zk: localhost:2181(CONNECTED) 2] quit

退出后，使用get命令获取数据的时候数据已经不存在了：

[zk: localhost:2181(CONNECTED) 0] get /test
Node does not exist: /test

（4）创建有序节点

[zk: localhost:2181(CONNECTED) 1] create -s /test "a"
Created /test0000000002

2、更新节点

（1）更新节点

[zk: localhost:2181(CONNECTED) 2] get /hadoop
nihao2020
cZxid = 0x4
ctime = Thu Oct 22 04:02:38 CST 2020
mZxid = 0x4
mtime = Thu Oct 22 04:02:38 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 9
numChildren = 0
[zk: localhost:2181(CONNECTED) 3] set /hadoop "zhaihuabing"
cZxid = 0x4
ctime = Thu Oct 22 04:02:38 CST 2020
mZxid = 0xb
mtime = Thu Oct 22 04:19:03 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 11
numChildren = 0
[zk: localhost:2181(CONNECTED) 4] get /hadoop
zhaihuabing
cZxid = 0x4
ctime = Thu Oct 22 04:02:38 CST 2020
mZxid = 0xb
mtime = Thu Oct 22 04:19:03 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 11
numChildren = 0
[zk: localhost:2181(CONNECTED) 5] 

每修改一次版本号加一

（2）带有版本号的更新

[zk: localhost:2181(CONNECTED) 0] get /hadoop
zhaihuabing
cZxid = 0x4
ctime = Thu Oct 22 04:02:38 CST 2020
mZxid = 0xb
mtime = Thu Oct 22 04:19:03 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 11
numChildren = 0
[zk: localhost:2181(CONNECTED) 1] set /hadoop "2020001" 0
version No is not valid : /hadoop
[zk: localhost:2181(CONNECTED) 2] set /hadoop "2020002" 1
cZxid = 0x4
ctime = Thu Oct 22 04:02:38 CST 2020
mZxid = 0xf
mtime = Thu Oct 22 04:26:19 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 2
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0
[zk: localhost:2181(CONNECTED) 3] get /hadoop
2020002
cZxid = 0x4
ctime = Thu Oct 22 04:02:38 CST 2020
mZxid = 0xf
mtime = Thu Oct 22 04:26:19 CST 2020
pZxid = 0x4
cversion = 0
dataVersion = 2
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0

第一次更新的时候版本号版本号不对应，提示版本号错误，在版本号一致的时候更新成功

3、删除节点

（1）删除节点

[zk: localhost:2181(CONNECTED) 4] delete /hadoop
[zk: localhost:2181(CONNECTED) 5] get /hadoop
Node does not exist: /hadoop

（2）带有版本号的删除

[zk: localhost:2181(CONNECTED) 8] set /hadoop "2020003"
Node does not exist: /hadoop
[zk: localhost:2181(CONNECTED) 9] create /hadoop "2020003"
Created /hadoop
[zk: localhost:2181(CONNECTED) 10] get /hadoop
2020003
cZxid = 0x13
ctime = Thu Oct 22 04:32:19 CST 2020
mZxid = 0x13
mtime = Thu Oct 22 04:32:19 CST 2020
pZxid = 0x13
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 0
[zk: localhost:2181(CONNECTED) 11] delete /hadoop 1
version No is not valid : /hadoop
[zk: localhost:2181(CONNECTED) 12] delete /hadoop 0
[zk: localhost:2181(CONNECTED) 13] get /hadoop
Node does not exist: /hadoop

带有版本号以后版本号只有在对应的情况下节点才能删除成功

（3）delete命令不能删除带有子节点的节点

[zk: localhost:2181(CONNECTED) 14] create /test "test"
Created /test
[zk: localhost:2181(CONNECTED) 15] create /test/t1 "t1"
Created /test/t1
[zk: localhost:2181(CONNECTED) 16] delete /test
Node not empty: /test

（4）使用rmr命令删除节点以及节点的子节点

[zk: localhost:2181(CONNECTED) 17] rmr /test
[zk: localhost:2181(CONNECTED) 18] get /test
Node does not exist: /test
[zk: localhost:2181(CONNECTED) 19] get /test/t1
Node does not exist: /test/t1