如何使用分布是缓存Hazelcast

使用Hazelcast

1.在pom.xml中配置对Hazelcast的依赖

<dependencies>
    <dependency>
        <groupId>com.hazelcast</groupId>
        <artifactId>hazelcast</artifactId>
        <version>3.5.2</version>
    </dependency>
</dependencies>

2.创建hazelcast server端和client端并运行

• 用hazelcast分布式Map和分布式queue创建一个简单的hazelcast java 程序
• 运行我们的程序两次创建集群中的两个Member(JVMS)
• 用hazelcast native java client API连接我们创建的hazelcast集群并访问分布式数据。

hazelcast server端程序代码

import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
import java.util.Map;
import java.util.Queue;
public class GettingStarted {
    public static void main( String[] args ) {
        HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance();
        Map<Integer, String> customers = hazelcastInstance.getMap( "customers" );
        customers.put( 1, "Joe" );
        customers.put( 2, "Ali" );
        customers.put( 3, "Avi" );
        System.out.println( "Customer with key 1: " + customers.get(1) );
        System.out.println( "Map Size:" + customers.size() );
        Queue<String> queueCustomers = hazelcastInstance.getQueue( "customers" );
        queueCustomers.offer( "Tom" );
        queueCustomers.offer( "Mary" );
        queueCustomers.offer( "Jane" );
        System.out.println( "First customer: " + queueCustomers.poll() );
        System.out.println( "Second customer: "+ queueCustomers.peek() );
        System.out.println( "Queue size: " + queueCustomers.size() );
    }
}

运行两次可以得到输出:

Members [2] {
    Member [127.0.0.1:5701]
    Member [127.0.0.1:5702] this
}

在pom.xml里面添加对hazelcast client的依赖:

<dependencies>
        <dependency>
            <groupId>com.hazelcast</groupId>
            <artifactId>hazelcast-client</artifactId>
            <version>3.5.2</version>
        </dependency>
</dependencies>

创建客户端程序:

package com.hazelcast.test;
import com.hazelcast.client.config.ClientConfig;
import com.hazelcast.client.HazelcastClient;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.core.IMap;
public class GettingStartedClient {
    public static void main( String[] args ) {
        ClientConfig clientConfig = new ClientConfig();
        HazelcastInstance client = HazelcastClient.newHazelcastClient( clientConfig );
        IMap map = client.getMap( "customers" );
        System.out.println( "Map Size:" + map.size() );
    }
}

运行客户端程序:

运行客户端后，客户端会连到先前创建的hazelcast集群，且输出map size为3.

在我们的这个示例中，没有配置任何Hazelcast配置文件。实际上，hazelcast会用默认的配置文件。

下面是hazelcast找寻配置文件的规则:

1.当一个hazelcast 节点启动的时候，它会先找寻hazelcast.config 系统属性。如果这个属性有被设置的话，那么hazelcast将会按照该属性的设置去找寻配置文件。

- Dhazelcast.config=<path to the hazelcast.xml>

2.如果找不到属性，那么hazelcast会在当前工作目录中找寻hazelcast.xml

3.如果在工作目录中找不到，会在class path寻找hazelcast.xml

4.如果还是找不到，hazelcast会加载默认的配置文件。hazlelcast.jar包中的hazelcast-default.xml

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