Spring Cloud Zookeeper 的作用
zookeeper是對分布式服務提供協調服務的apache開源項目。具體原理在上一講中《SpringCloud學習筆記七:Spring Cloud Zookeeper 服務管理》都具體描述過,這一講我們話不多說,直接上代碼。
本次實戰基于springcloud zookeeper進行開發,具體pom檔案添加如下内容
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-zookeeper-config</artifactId>
</dependency>
以及springcloud的版本管理
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Camden.SR2</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
建立測試類,具體邏輯在測試類中展現
import org.apache.zookeeper.*;
import org.apache.zookeeper.data.Stat;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.util.List;
public class ZookeeperApplicationTests {
String connectString = "127.0.0.1:2181";
int sessionTimeout = 2000;
private ZooKeeper zooCli;
/**
* 建立zookeeper服務
*
* @throws IOException
*/
@Before
public void init() throws IOException {
zooCli = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
@Override
public void process(WatchedEvent watchedEvent) {
List<String> children = null;
try {
children = zooCli.getChildren("/", true);
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
for (String child : children) {
System.out.println(child);
}
System.out.println("-----------------");
}
});
}
/**
* 建立節點
*
* @throws KeeperException
* @throws InterruptedException
*/
@Test
public void createNode() throws KeeperException, InterruptedException {
String path = zooCli.create("/bbb", "bruce is handsome".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
System.out.println(path);
}
/**
* 監聽節點狀态,實際監聽邏輯已經遷移到建立zookeeper服務方法中
*
* @throws KeeperException
* @throws InterruptedException
*/
@Test
public void getDataAndWatch() throws InterruptedException {
Thread.sleep(Long.MAX_VALUE);
}
/**
* 判斷zookeeper節點是否存在
*
* @throws KeeperException
* @throws InterruptedException
*/
@Test
public void exist() throws KeeperException, InterruptedException {
Stat stat = zooCli.exists("/bruce", false);
System.out.println(stat == null ? "not exist" : "exist");
}
}
在測試前,我們需要啟動zookeeper的服務端,不然代碼中監聽不到zookeeper服務,代碼會報錯。