1.通过org.apache.zookeeper.ZooKeeper来操作zookeeper服务
有关zookeeper服务的部署参见文：http://aiilive.blog.51cto.com/1925756/1684145 下文将有代码示例展示通过编码方式在应用中启动zookeeper服务。
ZooKeeper类对zookeeper服务的简单操作示例代码如下：
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package
secondriver.dubbo.client;
import
org.apache.zookeeper.*;
import
org.apache.zookeeper.data.Stat;
import
java.io.IOException;
import
java.util.List;
import
java.util.concurrent.TimeUnit;
/**
* Author : secondriver
*/
public
class
TestZookeeper {
public
static
void
main(String[] args)
throws
IOException, KeeperException, InterruptedException {
//创建zookeeper客户端
ZooKeeper zooKeeper =
new
ZooKeeper(
"192.168.88.153:2181"
,
1000
,
new
Watcher() {
@Override
public
void
process(WatchedEvent event) {
System.out.println(
"EventType:"
+ event.getType().name());
}
});
//获取"/" node下的所有子node
List<String> znodes = zooKeeper.getChildren(
"/"
,
true
);
for
(String path : znodes) {
System.out.println(path);
}
//创建开放权限的持久化node "/test"
String rs = zooKeeper.create(
"/test"
,
"test"
.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode
.PERSISTENT);
System.out.println(rs);
//同步获取"/test" node的数据
Stat stat =
new
Stat();
byte
[] data = zooKeeper.getData(
"/test"
,
true
, stat);
System.out.println(
"value="
+
new
String(data));
System.out.println(stat.toString());
//异步获取"/test" node的数据
zooKeeper.getData(
"/test"
,
true
,
new
AsyncCallback.DataCallback() {
@Override
public
void
processResult(
int
rc, String path, Object ctx,
byte
[] data, Stat stat) {
System.out.println(rc);
System.out.println(path);
System.out.println(ctx);
System.out.printf(
new
String(data));
System.out.println(stat.toString());
}
},
"Object ctx ..(提供的外部对象)"
);
TimeUnit.SECONDS.sleep(
10
);
zooKeeper.close();
}
}
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上述代码依赖zookeeper包
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<
dependency
>
<
groupId
>org.apache.zookeeper</
groupId
>
<
artifactId
>zookeeper</
artifactId
>
<
version
>3.4.6</
version
>
</
dependency
>
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2.通过zkclient操作zookeeper服务
zkclient github: https://github.com/sgroschupf/zkclient
后续有二次开发的版本：
项目： https://github.com/adyliu/zkclient
文档： https://github.com/adyliu/zkclient/wiki/tutorial
下文代码示例使用sgroschupf/zkclient,依赖Zookeeper包。
maven sgroschupf/zkclient
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<
dependency
>
<
groupId
>com.101tec</
groupId
>
<
artifactId
>zkclient</
artifactId
>
<
version
>0.5</
version
>
</
dependency
>
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应用内server+client:
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package
secondriver.dubbo.server;
import
org.I0Itec.zkclient.IDefaultNameSpace;
import
org.I0Itec.zkclient.ZkClient;
import
org.I0Itec.zkclient.ZkServer;
import
org.apache.zookeeper.CreateMode;
import
java.io.IOException;
/**
* Author : secondriver
*/
public
class
TestI0ItecZk {
public
static
void
main(String[] args)
throws
IOException {
//Server + Client
ZkServer zkServer =
new
ZkServer(
"D:/data"
,
"D:/log"
,
new
IDefaultNameSpace() {
@Override
public
void
createDefaultNameSpace(ZkClient zkClient) {
zkClient.create(
"/default"
,
"defalut-name-space"
, CreateMode.PERSISTENT);
}
});
zkServer.start();
ZkClient zkClient = zkServer.getZkClient();
boolean
exists = zkClient.exists(
"/default"
);
if
(exists) {
System.out.println(
"default name space init create succeed."
);
}
else
{
System.out.println(
"default name space init create failed."
);
}
System.in.read();
zkClient.close();
zkServer.shutdown();
}
}
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应用外部署server,使用client访问：
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package
secondriver.dubbo.server;
import
org.I0Itec.zkclient.ZkClient;
import
java.util.List;
/**
* Author : secondriver
*/
public
class
TestZkClient {
public
static
void
main(String[] args) {
//Only use client
ZkClient zkc =
new
ZkClient(
"192.168.88.153:2181,192.168.88.153:2182,192.168.88.153:2183"
);
List<String> childrens = zkc.getChildren(
"/"
);
for
(String child : childrens) {
System.out.println(child);
}
}
}
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下文代码示例使用adyliu/zkclient,同样依赖Zookeeper包，启动Zookeeper服务并做操作。
maven adyliu/zkclient:
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<
dependency
>
<
groupId
>com.github.adyliu</
groupId
>
<
artifactId
>zkclient</
artifactId
>
<
version
>2.1.1</
version
>
</
dependency
>
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package
secondriver.dubbo.server;
import
com.github.zkclient.*;
import
java.io.IOException;
import
java.util.List;
/**
* Author : secondriver
*/
public
class
TestZk {
public
static
void
main(String[] args)
throws
IOException {
String home = System.getProperty(
"user.home"
);
//创建zookeeper服务并启动
ZkServer zkServer =
new
ZkServer(home +
"/zookeeper/data"
, home +
"/zookeeper/log"
,
2181
);
zkServer.start();
//方式一
// ZkClient zkClient = new ZkClient("127.0.0.1:2181", 1000);
//方式二
ZkClient zkClient = zkServer.getZkClient();
String path =
"/test"
+ Math.random();
//数据监听
final
IZkDataListener dataListener =
new
IZkDataListener() {
@Override
public
void
handleDataChange(String dataPath,
byte
[] data)
throws
Exception {
System.out.println(dataPath +
" data change"
);
}
@Override
public
void
handleDataDeleted(String dataPath)
throws
Exception {
}
};
//结点（node）监听
final
IZkChildListener childListener =
new
IZkChildListener() {
@Override
public
void
handleChildChange(String parentPath, List<String> currentChildren)
throws
Exception {
System.out.println(parentPath +
" parentPath"
);
for
(String path : currentChildren) {
System.out.println(path);
}
}
};
//为指定node添加监听
zkClient.subscribeDataChanges(path, dataListener);
zkClient.subscribeChildChanges(
"/"
, childListener);
//zkclient操作Zookeeper服务
///检测node是否存在
if
(zkClient.exists(
"/zookeeper"
)) {
System.out.println(
"Exist zookeeper path"
);
}
else
{
System.out.println(
"Not Exist zookeeper path"
);
}
zkClient.createPersistent(path, path.getBytes());
byte
[] before = zkClient.readData(path);
System.out.println(
"before:"
+
new
String(before));
//以原子的方式更新指定的path node的数据
zkClient.cas(path,
new
IZkClient.DataUpdater() {
@Override
public
byte
[] update(
byte
[] currentData) {
return
new
String(currentData).concat(
new
String(
" updated"
)).getBytes();
}
});
byte
[] after = zkClient.readData(path);
System.out.println(
"after:"
+
new
String(after));
//取消指定path node的数据监听
zkClient.unsubscribeDataChanges(path, dataListener);
zkClient.writeData(path,
"new-data"
.getBytes());
byte
[] dataBytes = zkClient.readData(path);
String data =
new
String(dataBytes);
System.out.println(path +
" data :"
+ data);
System.in.read();
zkClient.close();
zkServer.shutdown();
}
}
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3. Zookeeper客户端和富Zookeeper框架之curator
本文转自 secondriver 51CTO博客，原文链接：http://blog.51cto.com/aiilive/1684451，如需转载请自行联系原作者
