1
123                                                                  节点数据
2
cZxid = 0x2                                                     节点的创建的事务id
3
ctime = Mon Feb 20 20:26:33 CST 2023         节点的创建时间
4
mZxid = 0x2                                                    节点的数据修改的事务id
5
mtime = Mon Feb 20 20:26:33 CST 2023        节点的数据的修改时间
6
pZxid = 0x2                                                     子节点个数变化的事务id
7
cversion = 0                                                    子节点变化的次数
8
dataVersion = 0                                              节点的数据变化次数
9
aclVersion = 0                                                 节点的权限策略变化的次数
10
ephemeralOwner = 0x0                                  当前节点是否是临时节点，0是永久节点，临时节点是sessionId的
11
dataLength = 3                                               节点的数据的长度
12
numChildren = 0                                             当前节点的子节点的个数

1
       <!--添加ZK的依赖-->
2
        <dependency>
3
            <groupId>org.apache.zookeeper</groupId>
4
            <artifactId>zookeeper</artifactId>
5
            <version>3.4.8</version>
6
        </dependency>

1
package cn.tedu.csmall.cart.webapi;
2

3
import org.apache.zookeeper.*;
4
import org.apache.zookeeper.data.Stat;
5
import org.junit.Before;
6
import org.junit.Test;
7
import java.io.IOException;
8
import java.util.List;
9
import java.util.concurrent.CountDownLatch;
10

11
public class ZookeeperTest {
12
    private ZooKeeper zk;
13

14
    @Before
15
    public void connect() throws IOException, InterruptedException {
16
        //获取zk对象
17
        //connectString:连接ZK的ip和端口号
18
        //sessionTimeout：会话超时时间
19
        //Watcher：监控合格者，用于监控连接是否建立
20
        //ZK底层是基于netty来完成连接
21
        //netty是基于nio的异步非阻塞的通信框架
22
        //非阻塞：无论连上与否都会向下执行
23
        //异步：ZK可能还没有建立连接或者还在监控中，测试线程可能已经资源
24
        final CountDownLatch cd = new CountDownLatch(1);
25
        zk=new ZooKeeper("127.0.0.1:2181", 5000, new Watcher() {
26
            @Override
27
            public void process(WatchedEvent watchedEvent) {
28
                if(watchedEvent.getState() == Event.KeeperState.SyncConnected){
29
                    System.out.println("连接成功");
30
                    cd.countDown();
31
                }
32
            }
33
        });
34
        //上面的连接线程执行完成之前，这个的测试线程不能执行
35
        //即使抢到了执行权也要阻塞
36
        cd.await();
37
        System.out.println("finish...");
38
    }
39
    //创建节点
40
    @Test
41
    public void createNode() throws InterruptedException, KeeperException {
42
        //path:节点路径
43
        //data:节点数据
44
        //acl: 权限策略
45
        //createMode: 创建节点的类型
46
        //返回值是节点名
47
       String s = zk.create("/log","hello zookeeper".getBytes(),
48
               ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
49
        System.out.println(s);
50
    }
51
    //修改节点数据
52
    @Test
53
    public void setData() throws InterruptedException, KeeperException {
54
        //path:节点路径
55
        //data:节点数据
56
        //version: 实际上指的就是dataVersion
57
        //当客户端尝试修改数据的时候，会校验version和节点的dataVersion是否一致
58
        //如果不一致就会报错BadVersionException
59
        //如果一致直接修改
60
        //如果不想受版本的控制，那么需要将version设置成-1
61
        Stat stat = zk.setData("/log", "bbb".getBytes(), -1);
62
    }
63
    //查看节点数据
64
    @Test
65
    public void getData() throws InterruptedException, KeeperException {
66
        Stat stat = new Stat();
67
        byte[] data = zk.getData("/log", null, stat);
68
        System.out.println(new String(data));
69
    }
70
    //获取子节点
71
    @Test
72
    public void getNode() throws InterruptedException, KeeperException {
73
        List<String> children = zk.getChildren("/", null);
74
        System.out.println(children);
75
    }
76
    //判断节点是否存在
77
    @Test
78
    public void exist() throws InterruptedException, KeeperException {
79
        Stat exists = zk.exists("/log", null);
80
        System.out.println(exists==null);
81
    }
82
    //删除节点
83
    @Test
84
    public void deleteNode() throws InterruptedException, KeeperException {
85
        zk.delete("/log",-1);
86
    }
87
}

1
zookeeper.connect=localhost:2181,localhost:2182,localhost:2183