redis简单分布式锁实现超简单的那种

1.下载安装启动redis 网上教程很多不说了

2. 先创建一个简单的Springcloud项目

<?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"><modelVersion>4.0.0</modelVersion><groupId>com.com.flybeer.demo</groupId><artifactId>cloud-demo</artifactId><packaging>pom</packaging><version>1.0-SNAPSHOT</version><modules><module>redis</module><module>redis2</module></modules><name>Maven</name><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><java.version>1.8</java.version><spring-cloud.version>Hoxton.SR8</spring-cloud.version><mybatis.starter.version>1.3.2</mybatis.starter.version><mybatis-plus.verion>3.2.0</mybatis-plus.verion><mapper.starter.version>2.0.2</mapper.starter.version><druid.starter.version>1.1.9</druid.starter.version><mysql.version>5.1.6</mysql.version><pageHelper.starter.version>1.2.3</pageHelper.starter.version><yijin.latest.version>1.0.0-SNAPSHOT</yijin.latest.version><fastDFS.client.version>1.26.1-RELEASE</fastDFS.client.version><fastjson.version>1.2.3</fastjson.version><spring-boot-starter-redis.version>1.4.6.RELEASE</spring-boot-starter-redis.version><commons-pool2.version>2.9.0</commons-pool2.version><redis.clients.version>2.9.0</redis.clients.version></properties><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.4.1</version><relativePath/> <!-- lookup parent from repository --></parent><dependencyManagement><dependencies><!-- springCloud --><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>${spring-cloud.version}</version><type>pom</type><scope>import</scope></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>${fastjson.version}</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-redis</artifactId><version>${spring-boot-starter-redis.version}</version></dependency><dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId><version>${redis.clients.version}</version></dependency><!-- spring2.X集成redis所需common-pool2 --><dependency><groupId>org.apache.commons</groupId><artifactId>commons-pool2</artifactId><version>${commons-pool2.version}</version></dependency></dependencies></dependencyManagement><build></build>
</project>

3.创建一个小module

pom文件

<?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>cloud-demo</artifactId><groupId>com.com.flybeer.demo</groupId><version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion><artifactId>redis</artifactId>
<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency><!--集成redis--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><dependency><groupId>org.apache.commons</groupId><artifactId>commons-pool2</artifactId></dependency><dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-aop</artifactId></dependency><dependency><groupId>org.redisson</groupId><artifactId>redisson</artifactId><version>3.9.1</version></dependency><dependency><groupId>io.gitlab.wmwtr</groupId><artifactId>spring-boot-devtools</artifactId><version>1.0.0.RELEASE</version><classifier>sources</classifier><type>java-source</type></dependency></dependencies></project>

写yml

server:port: 1011
spring:redis:host: localhostpassword:port: 6379jedis1:pool:max-active: 8max-wait: -1max-idle: 1

创建com.flybeer.config.RedisConfig.java文件把RedisTemplate<String, Serializable>，RedissonClient两个组件注入到springioc容器中

package com.flybeer.controller;import com.flybeer.unit.RedisUtils;
import com.flybeer.unit.ReturnUnit;import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationContext;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.web.bind.annotation.*;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;import javax.annotation.Resource;
import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;@RestController
@RequestMapping("redis")
public class Controller {@Autowiredprivate RedisTemplate<String, Serializable> redisTemplate;@Value("${server.port}")private String port;@Autowiredprivate ApplicationContext applicationContext;@Autowiredprivate RedissonClient redissonClient;@GetMapping("/buyGoods")public Map<String,Object> buyGoods(@RequestParam(value = "goodsId") String goodsId){String goodsLock="goodsLock"+goodsId;String value=Thread.currentThread().getName();RLock lock = redissonClient.getLock(goodsLock);lock.lock();Boolean aBoolean = false;/*  do{aBoolean =redisTemplate.opsForValue().setIfAbsent(goodsLock,value,10,TimeUnit.SECONDS);} while (!aBoolean);*/try {Serializable serializable = redisTemplate.opsForValue().get(goodsId);int num = Integer.parseInt(serializable.toString());if(num>0){//每次购买1件 用redis的单词递减1完成Long decrement = redisTemplate.opsForValue().decrement(goodsId);System.out.println("购买成功,库存剩余"+decrement+"件");return ReturnUnit.successReturn("购买成功,库存剩余"+decrement+"件"+port);}else {return ReturnUnit.successReturn("购买失败,库存不足");}}finally {//判断是不是自己家锁 是的话删掉if (lock.isLocked()&&lock.isHeldByCurrentThread()){lock.unlock();}//护士的是手动实现分布式锁 不借用插件 挺麻烦的 想看看 不想看不看/*if (redisTemplate.opsForValue().get(goodsLock).toString().equals(value)){redisTemplate.delete(goodsLock);}*///该方法是使用事务的方式关闭锁，平时不用 但面试可能会问道/*redisTemplate.watch(goodsLock);while (true) {if (redisTemplate.opsForValue().get(goodsLock).equals(value)) {redisTemplate.setEnableTransactionSupport(true);redisTemplate.multi();redisTemplate.delete(goodsLock);List<Object> exec = redisTemplate.exec();if (exec == null) {continue;}}redisTemplate.unwatch();break;}*///利用lua（读音 撸啊）表达式/*Jedis jedis = RedisUtils.getJedisPool();String script="if redis.call(\"get\",KEYS[1]) == ARGV[1]\n" +"then\n" +"    return redis.call(\"del\",KEYS[1])\n" +"else\n" +"    return 0\n" +"end";try {Object eval = jedis.eval(script, Collections.singletonList(goodsLock), Collections.singletonList(value));if ("1".equals(eval.toString())){System.out.println("关闭锁成功");}else {System.out.println("关闭锁失败");}}finally {if(null!=jedis){jedis.close();}}*/}}//初始化一个商品数量 让上面用@PostMapping("/initializeGoods")public Map<String,Object> initializeGoods(@RequestParam(value = "goodsId") String goodsId,@RequestParam(value = "num") int num){Serializable andSet = redisTemplate.opsForValue().getAndSet(goodsId, num);System.out.println(andSet);return ReturnUnit.successReturn("初始化商品成功");}
}

4.复制一份上面的小module端口号改成1012

server:
#只改这里就好port: 1012
spring:redis:host: localhostpassword:port: 6379jedis1:pool:max-active: 8max-wait: -1max-idle: 1

5.配置nginx负载均衡

#user  nobody;worker_processes  1;
events {worker_connections  1024;
}
http {include       mime.types;default_type  application/octet-stream;proxy_buffer_size 128k;proxy_buffers 32 128k;proxy_busy_buffers_size 128k;sendfile        on;keepalive_timeout  65;#主要就配置了这一行upstream org.tonny.balance {server 127.0.0.1:1011 weight=1;server 127.0.0.1:1012 weight=1;}#主要就配置了这一行server {listen       80;server_name  localhost;# 不带数据的请求，包括restful风格的请求#主要就配置了这一行location / {proxy_pass   http://org.tonny.balance;}#主要就配置了这一行# 静态文件，从这里获取location ~* \.(css|gif|png|jpeg|ico|svg)$ {root D:/App/nginx/apache-tomcat-7.0.92_1/webapps/ROOT;}# jsp类型的请求，从这里走location ~ \.jsp$ {proxy_pass   http://org.tonny.balance;}error_page   500 502 503 504  /50x.html;location = /50x.html {root   html;}
}

一共配置了两行
然后用jMetry做测试结果如下
1012

购买成功,库存剩余90件
购买成功,库存剩余84件
购买成功,库存剩余58件
购买成功,库存剩余57件
购买成功,库存剩余56件
购买成功,库存剩余55件
购买成功,库存剩余54件
购买成功,库存剩余52件
购买成功,库存剩余51件
购买成功,库存剩余50件
购买成功,库存剩余49件
购买成功,库存剩余47件
购买成功,库存剩余46件
购买成功,库存剩余45件
购买成功,库存剩余44件
购买成功,库存剩余43件
购买成功,库存剩余42件
购买成功,库存剩余41件
购买成功,库存剩余40件
购买成功,库存剩余39件
购买成功,库存剩余38件
购买成功,库存剩余37件
购买成功,库存剩余33件
购买成功,库存剩余32件
购买成功,库存剩余30件
购买成功,库存剩余29件
购买成功,库存剩余28件
购买成功,库存剩余27件
购买成功,库存剩余25件
购买成功,库存剩余24件
购买成功,库存剩余23件
购买成功,库存剩余22件
购买成功,库存剩余21件
购买成功,库存剩余20件
购买成功,库存剩余19件
购买成功,库存剩余18件
购买成功,库存剩余17件
购买成功,库存剩余16件
购买成功,库存剩余13件
购买成功,库存剩余12件
购买成功,库存剩余11件
购买成功,库存剩余10件
购买成功,库存剩余9件
购买成功,库存剩余8件
购买成功,库存剩余7件
购买成功,库存剩余6件
购买成功,库存剩余5件
购买成功,库存剩余4件
购买成功,库存剩余3件
1011

购买成功,库存剩余99件
购买成功,库存剩余98件
购买成功,库存剩余97件
购买成功,库存剩余96件
购买成功,库存剩余95件
购买成功,库存剩余94件
购买成功,库存剩余93件
购买成功,库存剩余92件
购买成功,库存剩余91件
购买成功,库存剩余89件
购买成功,库存剩余88件
购买成功,库存剩余87件
购买成功,库存剩余86件
购买成功,库存剩余85件
购买成功,库存剩余83件
购买成功,库存剩余82件
购买成功,库存剩余81件
购买成功,库存剩余80件
购买成功,库存剩余79件
购买成功,库存剩余78件
购买成功,库存剩余77件
购买成功,库存剩余76件
购买成功,库存剩余75件
购买成功,库存剩余74件
购买成功,库存剩余73件
购买成功,库存剩余72件
购买成功,库存剩余71件
购买成功,库存剩余70件
购买成功,库存剩余69件
购买成功,库存剩余68件
购买成功,库存剩余67件
购买成功,库存剩余66件
购买成功,库存剩余65件
购买成功,库存剩余64件
购买成功,库存剩余63件
购买成功,库存剩余62件
购买成功,库存剩余61件
购买成功,库存剩余60件
购买成功,库存剩余59件
购买成功,库存剩余53件
购买成功,库存剩余48件
购买成功,库存剩余36件
购买成功,库存剩余35件
购买成功,库存剩余34件
购买成功,库存剩余31件
购买成功,库存剩余26件
购买成功,库存剩余15件
购买成功,库存剩余14件
购买成功,库存剩余2件
购买成功,库存剩余1件
购买成功,库存剩余0件