Redis 实现分布式锁

最新推荐文章于 2024-08-21 10:01:21 发布

原创最新推荐文章于 2024-08-21 10:01:21 发布 · 179 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#redis #分布式 #分布式锁

面试系列同时被 3 个专栏收录

44 篇文章

订阅专栏

Redis系列

8 篇文章

订阅专栏

springboot

4 篇文章

订阅专栏

1、Redis 实现分布式锁

Springboot整合redis模拟房子商品超卖，多个服务间 + 保证同一时刻内 + 同一用户只能有一个请求。
建两个Module：boot_redis01，boot_redis02

<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>

	<parent>
	    <groupId>org.springframework.boot</groupId>
	    <artifactId>spring-boot-starter-parent</artifactId>
	    <version>2.3.3.RELEASE</version>
	    <relativePath/> <!-- lookup parent from repository -->
	</parent>

	<groupId>com.lun</groupId>
	<artifactId>boot_redis01</artifactId> <!--boot_redis02-->
	<version>1.0.0-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>boot_redis01</name> <!--boot_redis02-->
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>

		<!-- web+actuator -->
		<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>
		
		<!-- SpringBoot与Redis整合依赖 -->

		<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>
		
		<!-- jedis -->
		<dependency>
			<groupId>redis.clients</groupId>
			<artifactId>jedis</artifactId>
			<version>3.1.0</version>
		</dependency>

		<!-- Spring Boot AOP技术-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-aop</artifactId>
		</dependency>
		
		<!-- redisson -->
		<dependency>
			<groupId>org.redisson</groupId>
			<artifactId>redisson</artifactId>
			<version>3.13.4</version>
		</dependency>

		<!-- 一般通用基础配置 -->
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-devtools</artifactId>
		    <scope>runtime</scope>
		    <optional>true</optional>
		</dependency>
		
		<dependency>
		    <groupId>org.projectlombok</groupId>
		    <artifactId>lombok</artifactId>
		    <optional>true</optional>
		</dependency>
		
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-starter-test</artifactId><scope>test</scope>
		    <exclusions>
		        <exclusion>
		            <groupId>org.junit.vintage</groupId>
		            <artifactId>junit-vintage-engine</artifactId>
		        </exclusion>
		    </exclusions>
		</dependency>

	</dependencies>
	
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

Properties

server.port=1111
#2222
#=========================redis相关配香========================
#Redis数据库索引（默认方0）
spring.redis.database=0
#Redis服务器地址
spring.redis.host=192.168.111.147
#Redis服务器连接端口
spring.redis.port=6379
#Redis服务器连接密码（默认为空）
spring.redis.password=
#连接池最大连接数（使用负值表示没有限制）默认8
spring.redis.lettuce.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）默认-1
spring.redis.lettuce.pool.max-wait=-1
#连接池中的最大空闲连接默认8
spring.redis.lettuce.pool.max-idle=8
#连接池中的最小空闲连接默犬认0
spring.redis.lettuce.pool.min-idle=0

主启动类

@SpringBootApplication
public class BootRedis01Application{
    
    public static void main(String[] args){
        SpringApplication.run(BootRedis01Application.class, args);
    }
    
}

配置类

import java.io.Serializable;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

@Configuration
public class RedisConfig {

    @Bean
    public RedisTemplate<String, Serializable> redisTemplate(LettuceConnectionFactory connectionFactory){
        RedisTemplate<String, Serializable> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(connectionFactory);
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        return redisTemplate;
    }
    
}

Controller

@RestController
public class GoodController{

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Value("${server.port}")
    private String serverPort;

    @GetMapping("/buy_goods")
    public String buy_Goods(){

        String result = stringRedisTemplate.opsForValue().get("goods:001");// get key ====看看库存的数量够不够
        int goodsNumber = result == null ? 0 : Integer.parseInt(result);
        if(goodsNumber > 0){
            int realNumber = goodsNumber - 1;
            stringRedisTemplate.opsForValue().set("goods:001", String.valueOf(realNumber));
            System.out.println("成功买到商品，库存还剩下: "+ realNumber + " 件" + "\t服务提供端口" + serverPort);
            return "成功买到商品，库存还剩下:" + realNumber + " 件" + "\t服务提供端口" + serverPort;
        }else{
            System.out.println("商品已经售完/活动结束/调用超时,欢迎下次光临" + "\t服务提供端口" + serverPort);
        }

        return "商品已经售完/活动结束/调用超时,欢迎下次光临" + "\t服务提供端口" + serverPort;
    }
    
}

Redisson配置类

import org.redisson.Redisson;
import org.redisson.config.Config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
public class RedisConfig {

    @Bean
    public Redisson redisson() {
    	Config config = new Config();
    	config.useSingleServer().setAddress("redis://127.0.0.1:6379").setDatabase(0);
    	return (Redisson)Redisson.create(config);
    }
    
}

Redisson模板

public static final String REDIS_LOCK = "REDIS_LOCK";

@Autowired
private Redisson redisson;

@GetMapping("/doSomething")
public String doSomething(){

    RLock redissonLock = redisson.getLock(REDIS_LOCK);
    redissonLock.lock();
    try {
        //doSomething
    }finally {
    	//添加后，更保险
		if(redissonLock.isLocked() && redissonLock.isHeldByCurrentThread()) {
    		redissonLock.unlock();
    	}
    }
}

最终方案：

import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class GoodController{

	public static final String REDIS_LOCK = "REDIS_LOCK";
	
    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Value("${server.port}")
    private String serverPort;
    
    @Autowired
    private Redisson redisson;
    
    @GetMapping("/buy_goods")
    public String buy_Goods(){
    	
    	RLock redissonLock = redisson.getLock(REDIS_LOCK);
    	redissonLock.lock();
    	try {
	        String result = stringRedisTemplate.opsForValue().get("goods:001");// get key ====看看库存的数量够不够
	        int goodsNumber = result == null ? 0 : Integer.parseInt(result);
	        if(goodsNumber > 0){
	            int realNumber = goodsNumber - 1;
	            stringRedisTemplate.opsForValue().set("goods:001", String.valueOf(realNumber));
	            System.out.println("成功买到商品，库存还剩下: "+ realNumber + " 件" + "\t服务提供端口" + serverPort);
	            return "成功买到商品，库存还剩下:" + realNumber + " 件" + "\t服务提供端口" + serverPort;
	        }else{
	            System.out.println("商品已经售完/活动结束/调用超时,欢迎下次光临" + "\t服务提供端口" + serverPort);
	        }
	
	        return "商品已经售完/活动结束/调用超时,欢迎下次光临" + "\t服务提供端口" + serverPort;
    	}finally {
    		if(redissonLock.isLocked() && redissonLock.isHeldByCurrentThread()) {
    		redissonLock.unlock();
    		}
    	}
    }
    
}