zookeeper client: CuratorFramework (2)

 

CuratorFramework

(Documentation: http://curator.apache.org/curator-framework/index.html )

 

What is Framework?

 

1. What is Curator?
   
   Curator Framework is a high-level API of zookeeper;
   
   
2. What can Curators do?
   
   》Automatic link management, such as automatic reconnection, etc.;
   》Simple API;
   》Implementation of special functions, etc.; such as leader election, shared lock, etc.;
   
   

 Two ways of Curator instance creation
      A: Factory method

            CuratorFrameworkFactory.newClient();

      B: Use builder

CuratorFramework client = CuratorFrameworkFactory.builder()

.connectString(hosts)

.sessionTimeoutMs(sessionTimeout)

.connectionTimeoutMs(connectionTimeout)

.canBeReadOnly(true)

.retryPolicy(new ExponentialBackoffRetry(1000, 100))

.defaultData(null)

.build();

 

    After creating an instance, first execute the start() method;

//initialize the instance
client.start();


//close the instance
client.close();

 
      PS: Curator instances are thread-safe, so try to reuse the same instance;

 CuratorFramework API

    Curator uses a fluent interface style.

 

client.create().forPath("/head", new byte[0]);
client.delete().inBackground().forPath("/head");
client.create().withMode(CreateMode.EPHEMERAL_SEQUENTIAL).forPath("/head/child", new byte[0]);
client.getData().watched().inBackground().forPath("/test");

 

 

 Method: 

     http://curator.apache.org/curator-framework/index.html)

Namespaces

  To prevent conflicts, the same path may be added by adding the namespace

CuratorFramework    client = CuratorFrameworkFactory.builder().namespace("MyApp") ... build();
 ...
client.create().forPath("/test", data);
// node was actually written to: "/MyApp/test"