标签:Files netty jdk1.8 Java Zookeeper jar Program 客户端
Zookeeper Java 客户端实例
Zookeeper 的client端和服务端的代码没有分离,所以只用引用一个jar就行。这里版本最好与你服务端安装的zookeeper版本一致,以防一些兼容性问题。
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.5.8</version>
</dependency>
链接到zookeeper的服务器:
public static void connectZK() throws IOException, InterruptedException {
final CountDownLatch countDown = new CountDownLatch(1);
zk = new ZooKeeper(ZK_ADDRESS,5000,event -> {
if (event.getState() == Watcher.Event.KeeperState.SyncConnected && event.getType() == Watcher.Event.EventType.None){
countDown.countDown();
System.out.println("connected");
}
});
System.out.println("connecting please wait...");
countDown.await();
}
同步方式创建客户端的zk实例:
public static void createNote() throws KeeperException, InterruptedException {
zk.create("/AllenClient","Hello World".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
System.out.println("/AllenClient Created" );
}
异步方式创建节点,客户端实例:
public static void createNoteSync() throws KeeperException, InterruptedException {
zk.create("/AllenClientSync","Hello World".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,
CreateMode.PERSISTENT,(rc,path,ctx,name)->{
System.out.println(rc + " "+ path+" " + name+" " + ctx);
},"context");
System.out.println("/AllenClientSync Created" );
}
式修改zk数据:
public static void changeData() throws KeeperException, InterruptedException {
Stat stat = new Stat();
String path = "/AllenClient";
byte [] data = zk.getData(path,false,stat);
System.out.println("before the Change" + new String(data) );
zk.setData(path,"Hello Allen".getBytes(),stat.getVersion());
byte [] data1 = zk.getData(path,false,stat);
System.out.println("after the Change" + new String(data1) );
}
测试以上方法:
public static final String ZK_ADDRESS="192.168.0.101:2181";
public static ZooKeeper zk;
public static void main(String[] args) {
try {
connectZK();
createNote();
changeData();
createNoteSync();
} catch (IOException | KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
执行结构:
"C:\Program Files\Java\jdk1.8.0_202\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.2\lib\idea_rt.jar=59861:C:\Program Files\JetBrains\IntelliJ IDEA 2018.2.2\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files\Java\jdk1.8.0_202\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_202\jre\lib\rt.jar;C:\Users\Administrator\IdeaProjects\javaAA_L1\zookeeperTrainning\target\classes;C:\Users\Administrator\.m2\repository\org\apache\zookeeper\zookeeper\3.5.8\zookeeper-3.5.8.jar;C:\Users\Administrator\.m2\repository\org\apache\zookeeper\zookeeper-jute\3.5.8\zookeeper-jute-3.5.8.jar;C:\Users\Administrator\.m2\repository\org\apache\yetus\audience-annotations\0.5.0\audience-annotations-0.5.0.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-handler\4.1.48.Final\netty-handler-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-common\4.1.48.Final\netty-common-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-resolver\4.1.48.Final\netty-resolver-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-buffer\4.1.48.Final\netty-buffer-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-transport\4.1.48.Final\netty-transport-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-codec\4.1.48.Final\netty-codec-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-transport-native-epoll\4.1.48.Final\netty-transport-native-epoll-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\io\netty\netty-transport-native-unix-common\4.1.48.Final\netty-transport-native-unix-common-4.1.48.Final.jar;C:\Users\Administrator\.m2\repository\org\slf4j\slf4j-api\1.7.25\slf4j-api-1.7.25.jar;C:\Users\Administrator\.m2\repository\org\slf4j\slf4j-log4j12\1.7.25\slf4j-log4j12-1.7.25.jar;C:\Users\Administrator\.m2\repository\log4j\log4j\1.2.17\log4j-1.2.17.jar" allen.trainning.zk.ZKOfficialSimple
log4j:WARN No appenders could be found for logger (org.apache.zookeeper.ZooKeeper).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
connecting please wait...
connected
/AllenClient Created
before the ChangeHello World
after the ChangeHello Allen
/AllenClientSync Created
Process finished with exit code 0
在zk上查看执行结构:
WatchedEvent state:SyncConnected type:None path:null
[zk: localhost:2181(CONNECTED) 0] ls /
[Allen, AllenClient, AllenClientSync, zookeeper]
[zk: localhost:2181(CONNECTED) 1] get /AllenClient
Hello Allen
[zk: localhost:2181(CONNECTED) 3] get /AllenClientSync
Hello World
[zk: localhost:2181(CONNECTED) 4]
设置循环监听
在节点上添加监听,并实现循环监听:
1. 引入一个jason与object相互转换的工具
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.8.3</version>
</dependency>
2. 在代码中定义一个Watcher
Watcher watcher = new Watcher() {
@Override
public void process(WatchedEvent event) {
if(event.getType()==Event.EventType.NodeDataChanged
&& event.getPath()!=null
&& event.getPath().equals(path)){
System.out.println(event.getPath() + "date changed, please check !");
byte [] data=null;
try {
data = zk.getData(path,this,null);
Person allen = om.readValue(new String(data),Person.class);
System.out.println("Allen personal info changed to "+ allen.toString());
} catch (Exception e) {
e.printStackTrace();
}
}
}
};
3. 在代码中定义一个用来装数据的实体类
class Person{
private String name;
private String gender;
private int age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String toString(){
return "name:"+ name +" gender:"+ gender +" age:"+ age;
}
4. 设置循环监听节点
public static void listenNote() throws IOException, KeeperException, InterruptedException {
String path = "/AllenInfo";
Person allen = new Person();
allen.setName("Allen");
allen.setGender("Female");
allen.setAge(18);
ObjectMapper om = new ObjectMapper();
byte [] bytes = om.writeValueAsBytes(allen);
zk.create(path,bytes,ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.PERSISTENT);
#define Watcher
byte [] data =zk.getData(path,watcher,null);
Person allenNew = om.readValue(new String(data),Person.class);
System.out.println("Allen personal info is "+ allenNew.toString());
TimeUnit.SECONDS.sleep(Integer.MAX_VALUE);
}
测试方法:
public static final String ZK_ADDRESS="192.168.0.101:2181";
public static ZooKeeper zk;
public static void main(String[] args) {
try {
connectZK();
listenNote();
} catch (IOException | KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
执行结构:
当在zookeeper中去修改数据时候, 代码会自动的打印修改结构:
打印结果:
log4j:WARN No appenders could be found for logger (org.apache.zookeeper.ZooKeeper).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
connecting please wait...
connected
Allen personal info is name:Allen gender:Female age:18
/AllenInfodate changed, please check !
Allen personal info changed to name:Allen gender:Female age:19
/AllenInfodate changed, please check !
Allen personal info changed to name:Allen gender:Female age:20
/AllenInfodate changed, please check !
Allen personal info changed to name:Allen gender:Female age:21
标签:Files,netty,jdk1.8,Java,Zookeeper,jar,Program,客户端 来源: https://blog.csdn.net/pengweismile/article/details/115558817
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