【README】java 本地連接zk集群，https://blog.csdn.net/PacosonSWJTU/article/details/111404364??

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【1】判斷節點是否存在

/*** 測試 zk * @author pacoson**/ public class TestZK {/*** zk server 連接串 */private String connectString = "192.168.163.201:2181,192.168.163.202:2181,192.168.163.203:2181";/*** 超時時間*/private int sessionTimeout = 3000; /*** zk客戶端實例 */private ZooKeeper zkClient; /*** 0-獲取zk連接 * @throws IOException*/@Before public void init() throws IOException {/* 連接zk服務器 */zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {@Overridepublic void process(WatchedEvent event) {try {/*3-獲取子節點并監控節點變化*/System.out.println("-------watcher start---------");zkClient.getChildren("/", true).stream().forEach(System.out::println);System.out.println("-------watcher end ---------");} catch (KeeperException e) {e.printStackTrace();} catch (InterruptedException e) {e.printStackTrace();}}});}/*** 4-判斷節點是否存在 * @throws InterruptedException * @throws KeeperException */@Testpublic void exist() throws KeeperException, InterruptedException {Stat stat = zkClient.exists("/shanghai", false);System.out.println(stat);}}

log， 輸出的是 stat.toString() 方法? ?

-------watcher start--------- 12884901938,12884901938,1608390430303,1608390430303,0,0,0,0,13,0,12884901938

我們看下 zkcli on centos 查看 zk節點 /shanghai 的信息，如下：

[zk: localhost:2181(CONNECTED) 7] get /shanghai shanghai city cZxid = 0x300000032 ctime = Sat Dec 19 23:07:10 CST 2020 mZxid = 0x300000032 mtime = Sat Dec 19 23:07:10 CST 2020 pZxid = 0x300000032 cversion = 0 dataVersion = 0 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 13 numChildren = 0

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【2】 po出 Stat.toString()

public String toString() {try {java.io.ByteArrayOutputStream s =new java.io.ByteArrayOutputStream();CsvOutputArchive a_ = new CsvOutputArchive(s);a_.startRecord(this,"");a_.writeLong(czxid,"czxid");a_.writeLong(mzxid,"mzxid");a_.writeLong(ctime,"ctime");a_.writeLong(mtime,"mtime");a_.writeInt(version,"version");a_.writeInt(cversion,"cversion");a_.writeInt(aversion,"aversion");a_.writeLong(ephemeralOwner,"ephemeralOwner");a_.writeInt(dataLength,"dataLength");a_.writeInt(numChildren,"numChildren");a_.writeLong(pzxid,"pzxid");a_.endRecord(this,"");return new String(s.toByteArray(), "UTF-8");} catch (Throwable ex) {ex.printStackTrace();}return "ERROR";}

序號	key	描述
1	cZxid	創建事務編號
2	ctime	創建時間
3	mZxid	修改事務編號
4	mtime	修改時間
5	pZxid	最后更新的子節點
6	cversion	子節點變化編號
7	dataVersion	數據變化編號
8	aclVersion	訪問控制列表的變化號
9	ephemeralOwner	若是臨時節點，表示的是znode擁有者的session id，如果不是，則是0
10	dataLength	znode的數據長度
11	numChildren	znode的子節點個數

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