Zookeeper node additions and deletions to check the small demo

public class Zookeeperbase {


/*****zookeeper Address ********/
Static final String connect_addr = "112.124.121.34:2181";
/*****session Timeout Time ********/
static final int session_outtime = 5000;

/**** blocking execution is used to wait for the zookeeper connection to successfully send a successful signal *******/
Static final Countdownlatch Connectedsemaphore = new Countdownlatch (1);
Static final Countdownlatch ConnectedSemaphore2 = new Countdownlatch (2);

public static void Main (string[] args) throws Exception {
ZooKeeper ZK = new ZooKeeper (connect_addr, Session_outtime, New Watcher () {

@Override
public void process (Watchedevent event) {
Get Event Status
Keeperstate keeperstate = Event.getstate ();
Gets the type of event
EventType EventType = Event.gettype ();
If you are establishing a connection
if (keeperstate.syncconnected = = keeperstate) {
if (Eventtype.none = = EventType) {
If successful, sends a signal that the block continues to execute downwards.
Connectedsemaphore.countdown ();
try {
Thread.Sleep (3000);
} catch (Interruptedexception e) {
TODO auto-generated Catch block
E.printstacktrace ();
// }
System.out.println ("ZK establishes connection");
Connectedsemaphore.countdown ();
}
}
}
});

Blocking because the zookeeper is asynchronous and needs to be blocked
Connectedsemaphore.await ();

System.out.println ("carried out");
//
Thread.Sleep (5000);

Create parent Node
String ret = zk.create ("/testroot", "/testroot". GetBytes (), Ids.open_acl_unsafe, createmode.persistent);
System.out.println ("======" +ret);

Get node
byte[] data = Zk.getdata ("/testroot", false, NULL);
System.out.println (new String (data));
System.out.println (Zk.getchildren ("/testroot", false));

list<string> list = Zk.getchildren ("/testroot", false);
for (String path:list) {
SYSTEM.OUT.PRINTLN (path);
String Realpath = "/testroot/" +path;
System.out.println (New String (Zk.getdata (Realpath, FALSE, null)));
// }

Createmode.ephemeral temporary nodes can be used for distributed locks
String ret = zk.create ("/testroot/children", "Children data". GetBytes (), Ids.open_acl_unsafe, createmode.ephemeral) ;
System.out.println ("======" +ret);
Thread.Sleep (10*1000);
Create child nodes


Modify the value of a node
Zk.setdata ("/testroot", "Modify data Root". GetBytes (),-1);
byte[] data = Zk.getdata ("/testroot", false, NULL);
System.out.println (new String (data));

Determine if a node exists
System.out.println (zk.exists ("/testroot/a1", false));

Delete a node
Zk.delete ("/testroot", -1,new Asynccallback.voidcallback () {
//
@Override
public void Processresult (int r0, String path, Object ctx) {
try {
Thread.Sleep (1000);
} catch (Interruptedexception e) {
TODO auto-generated Catch block
E.printstacktrace ();
// }
System.out.println (R0);
SYSTEM.OUT.PRINTLN (path);
System.out.println (CTX);
// }
}, "a");
System.out.println ("========== continue to execute");

Thread.Sleep (10000);
Zk.close ();

}
}