1.Hazelcast介绍

Hazelcast是Hazelcast公司开源的一款分布式内存数据库产品，提供弹性可扩展、高性能的分布式内存计算。并通过提供诸如Map，Queue，ExecutorService，Lock和JCache等Java的许多开发人员友好的分布式实现。

Hazelcast优势

Hazelcast提供开源版本。
Hazelcast无需安装，只是个极小jar包。
Hazelcast提供开箱即用的分布式数据结构，如Map，Queue，MultiMap，Topic，Lock和Executor。
Hazelcast集群非传统主从关系，避免了单点故障；集群中所有成员共同分担集群功能。
Hazelcast集群提供弹性扩展，新成员在内存不足或负载过高时能动态加入集群。
Hazelcast集群中成员分担数据缓存的同时互相冗余备份其他成员数据，防止某成员离线后数据丢失。
Hazelcast提供SPI接口支持用户自定义分布式数据结构。

Hazelcast适用场景

频繁读写数据
需要高可用分布式缓存
内存行NoSql存储
分布式环境中弹性扩展

2.代码工程

pom.xml

<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0"         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <parent>        <artifactId>springboot-demo</artifactId>        <groupId>com.et</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>
    <artifactId>hazelcast</artifactId>
    <properties>        <maven.compiler.source>8</maven.compiler.source>        <maven.compiler.target>8</maven.compiler.target>    </properties>    <dependencies>
        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>
        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-autoconfigure</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-test</artifactId>            <scope>test</scope>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-cache</artifactId>        </dependency>        <dependency>            <groupId>com.hazelcast</groupId>            <artifactId>hazelcast-all</artifactId>            <version>4.0.2</version>        </dependency>    </dependencies>

</project>

hazelcast.xml

<hazelcast        xsi:schemaLocation="http://www.hazelcast.com/schema/config   http://www.hazelcast.com/schema/config/hazelcast-config-3.12.12.xsd"        xmlns="http://www.hazelcast.com/schema/config"        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">    <instance-name>XML_Hazelcast_Instance</instance-name>    <network>        <join>            <multicast enabled="false">            </multicast>            <tcp-ip enabled="true">                <member>10.11.68.77</member>            </tcp-ip>        </join>    </network></hazelcast>

application.yaml

server:  port: 8090

entity

package com.et.hazelcast.entity;import java.io.Serializable;public class Employee implements Serializable{   private static final long serialVersionUID = 1L;   private int empId;   private String name;   private String department;   public Employee(Integer id, String name, String department) {      super();      this.empId = id;      this.name = name;      this.department = department;   }   public int getEmpId() {      return empId;   }   public void setEmpId(int empId) {      this.empId = empId;   }   public String getName() {      return name;   }   public void setName(String name) {      this.name = name;   }   public String getDepartment() {      return department;   }   public void setDepartment(String department) {      this.department = department;   }   @Override   public String toString() {      return "Employee [empId=" + empId + ", name=" + name + ", department=" + department + "]";   }}

controller

package com.et.hazelcast.controller;
import com.et.hazelcast.entity.Employee;import org.springframework.cache.annotation.Cacheable;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.ResponseBody;
import java.util.HashMap;import java.util.Map;
@Controllerpublic class HelloWorldController {    @RequestMapping("/hello")    @ResponseBody    public Map<String, Object> showHelloWorld(){        Map<String, Object> map = new HashMap<>();        map.put("msg", "HelloWorld");        return map;    }    @Cacheable(value = "employee")    @GetMapping("employee/{id}")    @ResponseBody    public Employee getSubscriber(@PathVariable("id") int id) throws            InterruptedException {        System.out.println("Finding employee information with id " + id + " ...");        return new Employee(id, "John Smith", "CS");    }}

准备三个启动类

package com.et.hazelcast;
import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cache.annotation.EnableCaching;
@EnableCaching@SpringBootApplicationpublic class HazelcastNode1Starter {
   public static void main(String[] args) {      SpringApplication.run(HazelcastNode1Starter.class, args);   }
}

package com.et.hazelcast;
import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cache.annotation.EnableCaching;@EnableCaching@SpringBootApplicationpublic class HazelcastNode2Starter {    public static void main(String[] args) {        SpringApplication.run(HazelcastNode2Starter.class, args);    }}

package com.et.hazelcast;
import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cache.annotation.EnableCaching;@EnableCaching@SpringBootApplicationpublic class HazelcastNode3Starter {    public static void main(String[] args) {        SpringApplication.run(HazelcastNode3Starter.class, args);    }}

java代码客户端

这个代码中最关键的参数是需要设置之前定义的cluster-name “hazelcast-cluster”。这样就实现了对hazelcast集群中map的调用。上述过程中，如果关闭任意一个hazelcast节点，上述缓存中的数据都可用。很好的实现了分布式。

package com.et.hazelcast;
import com.hazelcast.client.HazelcastClient;import com.hazelcast.client.config.ClientConfig;import com.hazelcast.core.HazelcastInstance;import lombok.extern.slf4j.Slf4j;
import java.util.Map;
@Slf4jpublic class HazelcastGetStartClient {    public static void main(String[] args) {        ClientConfig clientConfig = new ClientConfig();        clientConfig.setClusterName("hazelcast-cluster");        HazelcastInstance instance = HazelcastClient.newHazelcastClient(clientConfig);        Map<Integer, String> clusterMap = instance.getMap("map");    }
}

代码仓库

https://github.com/Harries/springboot-demo

3.测试

端口修改8088，启动HazelcastNode1Starter
端口修改8089，启动HazelcastNode2Starter
端口修改8090，启动HazelcastNode3Starter

Members {size:3, ver:5} [ Member [10.11.68.77]:5701 - 2faf3b2d-76f3-493c-be48-d19d25aeb581 this Member [10.11.68.77]:5702 - 63caca7f-f8ba-4b0a-989a-6e86a199fb72 Member [10.11.68.77]:5703 - 3e9fa03c-72f4-4866-8904-73b908c4005d]

浏览器输入http://localhost:8088/employee/6，存入数据到hazelcast里面，控制台输出

Finding employee information with id 6 ...

浏览器输入http://localhost:8089/employee/6，可以直接获取缓存数据，控制台不会打印日志出来

浏览器输入http://localhost:8090/employee/6，可以直接获取缓存数据，控制台不会打印日志出来

4.引用

http://element-ui.cn/news/show-552564.html
http://www.liuhaihua.cn/archives/710310.html

ITPub博客

Spring集成hazelcast实现分布式缓存