zookeeper

pom.xml配置zookeeper

<!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.4.14</version>
        </dependency>

创建create

String result = zk.create("/test_node",
"test".getBytes(), 
ZooDefs.Ids.OPEN_ACL_UNSAFE, 
CreateMode.PERSISTENT);

异步

class CreateCallBack implements AsyncCallback.StringCallback{
    public void processResult(int rc, String path, Object ctx, String name) {
        System.out.println("创建节点: " + path);
        System.out.println((String)ctx);
    }
}

String ctx = "{'create':'success'}";
        zk.create("/asyn_node",
                "test".getBytes(),
                ZooDefs.Ids.OPEN_ACL_UNSAFE,
                CreateMode.PERSISTENT,
                new CreateCallBack(),
                ctx
                );

修改节点数据

zk.setData("/test_node","update_data".getBytes(),0);

删除

zk.delete("/test_node",1);

ACL

String writerId = DigestAuthenticationProvider.generateDigest("writer:123456");
        String readerId = DigestAuthenticationProvider.generateDigest("reader:654321");
        Id wId = new Id("digest", writerId);
        Id rId = new Id("digest", readerId);
        List<ACL> aclList = new ArrayList<ACL>();
        aclList.add(new ACL(ZooDefs.Perms.ALL, wId));
        aclList.add(new ACL(ZooDefs.Perms.READ, rId));
        zk.create("/acl_node", "node".getBytes(), aclList, CreateMode.PERSISTENT);

zk.addAuthInfo("digest","writer:123456".getBytes());
        zk.create("/acl_node/digest_node","digest_node".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);

客户端Curator

zookeeper原生api的不足之处
超时重连，不支持自动，需要手动重连
Watch注册一次会失效
不支持递归创建节点

<dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-recipes</artifactId>
            <version>4.2.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.curator</groupId>
            <artifactId>curator-framework</artifactId>
            <version>4.2.0</version>
        </dependency>

CuratorFramework client = CuratorFrameworkFactory.builder().connectString("127.0.0.1:2181")
                .sessionTimeoutMs(15000)
                .retryPolicy(new RetryNTimes(3,5000)).
                namespace("namespace").build();
        client.start();
        try {
            client.create().creatingParentsIfNeeded().
                    withMode(CreateMode.PERSISTENT).
                    withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE).forPath("/super/test","testdata".getBytes());
        }catch (Exception e){
            e.printStackTrace();
        }