Hazelcast 应用程序
Hazelcast 可以单独运行（单节点），也可以运行多个节点形成集群。让我们先尝试启动单个实例。
单实例
示例
现在，让我们尝试创建和使用 Hazelcast 集群的单个实例。为此，我们将创建 SingleInstanceHazelcastExample.java 文件。
package com.example.demo;
import java.util.Map;
import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
public class SingleInstanceHazelcastExample {
public static void main(String... args){
//initialize hazelcast server/instance
HazelcastInstance hazelcast = Hazelcast.newHazelcastInstance();
System.out.println(“Hello world”);
// perform a graceful shutdown
hazelcast.shutdown();
}
}
现在让我们编译代码并执行它-
mvn clean install
java-cp target/demo-0.0.1-SNAPSHOT.jar
com.example.demo.SingleInstanceHazelcastExample
输出
如果你执行上面的代码，输出将是-
然而，更重要的是，您还会注意到 Hazelcast 的日志行，这表示 Hazelcast 已启动。由于我们仅运行此代码一次，即单个 JVM，因此我们的集群中将只有一个成员。
Jan 30, 2021 10:26:51 AM com.hazelcast.config.XmlConfigLocator
INFO: Loading 'hazelcast-default.xml' from classpath.
Jan 30, 2021 10:26:51 AM com.hazelcast.instance.AddressPicker
INFO: [LOCAL] [dev] [3.12.12] Prefer IPv4 stack is true.
Jan 30, 2021 10:26:52 AM com.hazelcast.instance.AddressPicker
INFO: [LOCAL] [dev] [3.12.12] Picked [localhost]:5701, using socket
ServerSocket[addr=/0:0:0:0:0:0:0:0,localport=5701], bind any local is true
Jan 30, 2021 10:26:52 AM com.hazelcast.system
...
Members {size:1, ver:1} [
Member [localhost]:5701-9b764311-9f74-40e5-8a0a-85193bce227b this
]
Jan 30, 2021 10:26:56 AM com.hazelcast.core.LifecycleService
INFO: [localhost]:5701 [dev] [3.12.12] [localhost]:5701 is STARTED
...
You will also notice log lines from Hazelcast at the end which signifies
Hazelcast was shutdown:
INFO: [localhost]:5701 [dev] [3.12.12] Hazelcast Shutdown is completed in 784 ms.
Jan 30, 2021 10:26:57 AM com.hazelcast.core.LifecycleService
INFO: [localhost]:5701 [dev] [3.12.12] [localhost]:5701 is SHUTDOWN
集群：多实例
现在，让我们创建用于多实例集群的 MultiInstanceHazelcastExample.java 文件（如下所示）。
package com.example.demo;
import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
public class MultiInstanceHazelcastExample {
public static void main(String... args) throws InterruptedException{
//initialize hazelcast server/instance
HazelcastInstance hazelcast = Hazelcast.newHazelcastInstance();
//print the socket address of this member and also the size of the cluster
System.out.println(String.format("[%s]: No. of hazelcast members: %s",
hazelcast.getCluster().getLocalMember().getSocketAddress(),
hazelcast.getCluster().getMembers().size()));
// wait for the member to join
Thread.sleep(30000);
//perform a graceful shutdown
hazelcast.shutdown();
}
}
让我们在
两个不同的 shell 上执行以下命令-
java-cp .\target\demo-0.0.1-SNAPSHOT.jar
com.example.demo.MultiInstanceHazelcastExample
您会在
第一个 shell 上注意到 Hazelcast 实例已启动并已分配成员。请注意输出的最后一行，它表示有一个
单个成员使用端口 5701。
Jan 30, 2021 12:20:21 PM com.hazelcast.internal.cluster.ClusterService
INFO: [localhost]:5701 [dev] [3.12.12]
Members {size:1, ver:1} [
Member [localhost]:5701-b0d5607b-47ab-47a2-b0eb-6c17c031fc2f this
]
Jan 30, 2021 12:20:21 PM com.hazelcast.core.LifecycleService
INFO: [localhost]:5701 [dev] [3.12.12] [localhost]:5701 is STARTED
[/localhost:5701]: No. of hazelcast members: 1
您会在
第二个 shell 上注意到一个 Hazelcast 实例已经加入了第一个实例。请注意输出的最后一行，它表示现在有
两个成员使用端口 5702。
INFO: [localhost]:5702 [dev] [3.12.12]
Members {size:2, ver:2} [
Member [localhost]:5701-b0d5607b-47ab-47a2-b0eb-6c17c031fc2f
Member [localhost]:5702-037b5fd9-1a1e-46f2-ae59-14c7b9724ec6 this
]
Jan 30, 2021 12:20:46 PM com.hazelcast.core.LifecycleService
INFO: [localhost]:5702 [dev] [3.12.12] [localhost]:5702 is STARTED
[/localhost:5702]: No. of hazelcast members: 2
