springboot整合curator实现分布式锁模拟抢购场景
2024-04-15 02:42:06
文章目录
- 1.环境说明
- 2.maven依赖
- 3.代码实现
- 3.1.Redis
- 3.1.1.配置文件
- 3.1.2.redisTemplate配置
- 3.2.Curator
- 3.1.1.配置文件
- 3.1.2.Curator配置
- 3.2.测试
1.环境说明
| 序号 | 名称 | 版本 | 说明 |
|---|---|---|---|
| 1 | springboot | 2.2.1.RELEASE | |
| 2 | curator | 2.8.0 | zookeeper的封装框架 |
| 3 | redis | 5.0.9 | 下载路径: https://github.com/tporadowski/redis/releases/download/v5.0.9/Redis-x64-5.0.9.zip |
| 4 | zookeeper | 3.4.14 | 下载路径: https://mirrors.tuna.tsinghua.edu.cn/apache/zookeeper/zookeeper-3.4.14/zookeeper-3.4.14.tar.gz |
备注: redis和zookeeper的安装启动这里不做说明
2.maven依赖
<!--curator-->
<dependency><groupId>org.apache.curator</groupId><artifactId>curator-framework</artifactId><version>2.8.0</version>
</dependency>
<dependency><groupId>org.apache.curator</groupId><artifactId>curator-recipes</artifactId><version>2.8.0</version>
</dependency><!--redis-->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<!--jackson-->
<dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId>
</dependency>
<dependency><groupId>org.apache.commons</groupId><artifactId>commons-pool2</artifactId><version>2.6.1</version>
</dependency><!--zookeeper-->
<dependency><groupId>org.apache.zookeeper</groupId><artifactId>zookeeper</artifactId><version>3.4.10</version>
</dependency>
3.代码实现
3.1.Redis
3.1.1.配置文件
#redis的ip
spring.redis.host=127.0.0.1
#端口
spring.redis.port=6379
#密码:redis配置文件设置（默认为空）
spring.redis.password=123456
# 连接池最大连接数（使用负值表示没有限制）
spring.redis.jedis.pool.max-active=8
# 连接池最大阻塞等待时间（使用负值表示没有限制）
spring.redis.jedis.pool.max-wait=1000
# 连接池中的最大空闲连接
spring.redis.lettuce.pool.max-idle=1
# 连接池中的最小空闲连接
spring.redis.lettuce.pool.min-idle=0
# 连接超时时间（毫秒）
spring.redis.timeout=10000
3.1.2.redisTemplate配置
package com.tt.tt.redis.config;import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.jsontype.impl.LaissezFaireSubTypeValidator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;/*** @author 小枫* @version 1.0.0* @date 2020/6/18 20:18* @desciption MyRedisConfig*/
@Configuration
public class MyRedisConfig {@Beanpublic RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory factory){RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();redisTemplate.setConnectionFactory(factory);ObjectMapper objectMapper=new ObjectMapper();objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);objectMapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance, ObjectMapper.DefaultTyping.NON_FINAL);Jackson2JsonRedisSerializer jackson2JsonRedisSerializer=new Jackson2JsonRedisSerializer(Object.class);jackson2JsonRedisSerializer.setObjectMapper(objectMapper);//1.设置key的序列化方式redisTemplate.setKeySerializer(new StringRedisSerializer());redisTemplate.setHashKeySerializer(new StringRedisSerializer());//2.设置value的序列化方式redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);redisTemplate.setHashValueSerializer(jackson2JsonRedisSerializer);return redisTemplate;}
}
3.2.Curator
3.1.1.配置文件
## zookeeper: curator
#重试次数
curator.retryCount=5
#重试间隔时间(ms)
curator.elapsedTimeMs=5000
# zookeeper 地址
curator.connectString=127.0.0.1:2181
# session超时时间
curator.sessionTimeoutMs=60000
# 连接超时时间
curator.connectionTimeoutMs=5000
3.1.2.Curator配置
package com.tt.tt.zookeeper.service;import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.cache.PathChildrenCache;
import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.ZooDefs;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.concurrent.CountDownLatch;/*** @author 小枫* @version 1.0.0* @date 2020/6/18 20:05* @desciption DistributedLockByCuratorServiceImpl*/
@Service
public class DistributedLockByCuratorServiceImpl implements InitializingBean {private final static String ROOT_PATH_LOCK = "rootLock";private CountDownLatch countDownLatch = new CountDownLatch(1);@Autowiredprivate CuratorFramework curatorFramework;@Overridepublic void afterPropertiesSet() throws Exception {curatorFramework= curatorFramework.usingNamespace("distributedLock");String path = "/" + ROOT_PATH_LOCK;if (null==curatorFramework.checkExists().forPath(path)){curatorFramework.create().creatingParentsIfNeeded().withMode(CreateMode.PERSISTENT).withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE).forPath(path);addWatcher(ROOT_PATH_LOCK);}}/*** 创建 watcher 事件*/private void addWatcher(String path) throws Exception {String keyPath;if (path.equals(ROOT_PATH_LOCK)) {keyPath = "/" + path;} else {keyPath = "/" + ROOT_PATH_LOCK + "/" + path;}final PathChildrenCache cache = new PathChildrenCache(curatorFramework, keyPath, false);cache.start(PathChildrenCache.StartMode.POST_INITIALIZED_EVENT);cache.getListenable().addListener((client, event) -> {if (event.getType().equals(PathChildrenCacheEvent.Type.CHILD_REMOVED)) {String oldPath = event.getData().getPath();if (oldPath.contains(path)) {//释放计数器，让当前的请求获取锁countDownLatch.countDown();}}});}/*** 获取分布式锁*/public void acquireDistributedLock(String path) throws Exception {String keyPath = "/" + ROOT_PATH_LOCK + "/" + path;while (true) {try {curatorFramework.create().creatingParentsIfNeeded().withMode(CreateMode.EPHEMERAL).withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE).forPath(keyPath);break;} catch (Exception e) {try {if (countDownLatch.getCount() <= 0) {countDownLatch = new CountDownLatch(1);}countDownLatch.await();} catch (InterruptedException e1) {e1.printStackTrace();}}}}/*** 释放分布式锁*/public boolean releaseDistributedLock(String path) {try {String keyPath = "/" + ROOT_PATH_LOCK + "/" + path;if (curatorFramework.checkExists().forPath(keyPath) != null) {curatorFramework.delete().forPath(keyPath);}} catch (Exception e) {return false;}return true;}
}
3.2.测试
高并发测试工具: jmeter 方法: https://blog.csdn.net/qq_42513284/article/details/94662461
package com.tt.tt.controller;import com.tt.tt.zookeeper.service.DistributedLockByCuratorServiceImpl;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.Map;
import java.util.concurrent.TimeUnit;/*** @author 小枫* @version 1.0.0* @date 2020/6/17 20:59* @desciption DistributeLockContrller: 在redis中预设苹果手机的抢购数量(100)：set productAppleNum 100*/
@RestController
@RequestMapping("/api")
public class DistributeLockContrller {@Autowiredprivate RedisTemplate redisTemplate;@Autowiredprivate DistributedLockByCuratorServiceImpl distributedLockByCuratorService;@Autowiredprivate CuratorFramework curatorFramework;@RequestMapping("/lock")public String distributeLockTest() throws Exception {String path = "/productApple";String msg = "抢购失败";InterProcessMutex mutex = null;boolean acquire = false;int productNum = 0;//为何要先查一下redis中的苹果手机: redis的读写性能非常高,// 如果查询redis中苹果手机的数量都<=0的话，直接返回失败，极大的提高了并发量//Object num =null;Object num = redisTemplate.opsForValue().get("productAppleNum");if (null != num) {productNum = Integer.parseInt(String.valueOf(num));if (productNum <= 0) {msg = "苹果手机已经被抢购完...";System.out.println(msg);throw new Exception(msg);}}try {//1.分布式锁:避免苹果手机出现超卖的严重后果mutex = new InterProcessMutex(curatorFramework, path);//获取锁acquire = mutex.acquire(5000, TimeUnit.MILLISECONDS);if (acquire) {//2.也可用数据库保存抢购苹果手机的数量//获取redis中苹果手机的数量num = redisTemplate.opsForValue().get("productAppleNum");if (null != num) {productNum = Integer.parseInt(String.valueOf(num));if (productNum > 0) {//3.抢购成功, redis中苹果手机的数量redisTemplate.getConnectionFactory().getConnection().decr(redisTemplate.getKeySerializer().serialize("productAppleNum"));msg = "苹果手机抢购成功!";System.out.println(msg);return msg;} else {msg = "苹果手机已经被抢购完...";System.out.println(msg);throw new Exception(msg);}}}} catch (Exception e) {e.printStackTrace();throw new Exception(msg);} finally {try {//释放锁if (null != mutex && acquire) {mutex.release();System.out.println("释放锁成功!");}} catch (Exception e) {e.printStackTrace();}}msg = "failed !";throw new Exception(msg);}@RequestMapping("/lock2")public String distributeLockTest2() throws Exception {String path = "productApple"; //注意不要加/String msg = "抢购失败";InterProcessMutex mutex = null;Integer productNum = 0;Object num = redisTemplate.opsForValue().get("productAppleNum");if (null != num) {productNum = Integer.parseInt(String.valueOf(num));if (productNum <= 0) {msg = "苹果手机已经被抢购完...";System.out.println(msg);throw new Exception(msg);}}try {distributedLockByCuratorService.acquireDistributedLock(path);num = redisTemplate.opsForValue().get("productAppleNum");if (null != num) {productNum = Integer.parseInt(String.valueOf(num));if (productNum > 0) {redisTemplate.getConnectionFactory().getConnection().decr(redisTemplate.getKeySerializer().serialize("productAppleNum"));msg = "苹果手机抢购成功!";System.out.println(msg);return msg;} else {msg = "苹果手机已经被抢购完...";System.out.println(msg);throw new Exception(msg);}}} catch (Exception e) {e.printStackTrace();throw new Exception(msg);} finally {try {boolean b = distributedLockByCuratorService.releaseDistributedLock(path);System.out.println("释放锁:"+b);} catch (Exception e) {e.printStackTrace();System.out.println("释放锁失败:"+false);}}msg = "failed";throw new Exception(msg);}
}
测试方式: 1000个线程，间隔1s循环10次
测试结果:
- 多次测试并未发现redis设置的数量变为负值（即超卖现象）
- 方式一比方式二的并发量高
- 方式一问题：偶尔出现redis设置的数量大于0的现象
- 方式二问题 : redis设置的数量均为0，但是偶尔出现请求超时，未得到响应
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