Spring Boot使用Redis实现分布式锁

在分布式系统中，分布式锁是一种解决并发问题的常用技术。Redis由于其高性能和丰富的特性，成为实现分布式锁的理想选择。本文将详细介绍如何在Spring Boot应用中使用Redis实现分布式锁。

一、环境准备

1. 安装Redis：确保已经安装并运行Redis服务。
2. Spring Boot项目：确保已经创建并配置好了Spring Boot项目。
3. 添加依赖：在 pom.xml中添加Spring Data Redis和Lettuce依赖。

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
    <groupId>io.lettuce.core</groupId>
    <artifactId>lettuce-core</artifactId>
</dependency>
​

二、Redis配置

在 application.properties或 application.yml文件中配置Redis连接信息。

spring.redis.host=localhost
spring.redis.port=6379
spring.redis.password=yourpassword # 如果Redis设置了密码
​

三、实现分布式锁

1. 创建Redis配置类

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.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;

@Configuration
public class RedisConfig {

    @Bean
    public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory factory) {
        return new StringRedisTemplate(factory);
    }

    @Bean
    public ValueOperations<String, String> valueOperations(StringRedisTemplate stringRedisTemplate) {
        return stringRedisTemplate.opsForValue();
    }
}
​

2. 创建分布式锁工具类

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Component;

import java.util.concurrent.TimeUnit;

@Component
public class RedisLock {

    @Autowired
    private ValueOperations<String, String> valueOperations;

    private static final long LOCK_EXPIRE = 30L; // 锁过期时间，30秒
    private static final String LOCK_VALUE = "LOCKED";

    public boolean lock(String key) {
        Boolean success = valueOperations.setIfAbsent(key, LOCK_VALUE, LOCK_EXPIRE, TimeUnit.SECONDS);
        return success != null && success;
    }

    public void unlock(String key) {
        valueOperations.getOperations().delete(key);
    }
}
​

3. 使用分布式锁

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class LockController {

    @Autowired
    private RedisLock redisLock;

    @GetMapping("/lock")
    public String lock() {
        String key = "myLock";
        if (redisLock.lock(key)) {
            try {
                // 业务逻辑
                Thread.sleep(2000); // 模拟业务处理时间
                return "Locked and processed";
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                redisLock.unlock(key);
            }
        } else {
            return "Failed to acquire lock";
        }
        return "Unexpected error";
    }
}
​