<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
    <groupId>redis.clients</groupId>
    <artifactId>jedis</artifactId>
    <version>3.1.0</version>
</dependency>

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
import redis.clients.jedis.Transaction;
import redis.clients.jedis.exceptions.JedisException;
import java.util.List;
import java.util.UUID;
/**
 * @author swadian
 * @date 2022/3/4
 * @Version 1.0
 * @describetion Redis分布式鎖原理
 */
public class DistributedLock {
    //redis連接池
    private static JedisPool jedisPool;
    static {
        JedisPoolConfig config = new JedisPoolConfig();
        // 設(shè)置最大連接數(shù)
        config.setMaxTotal(200);
        // 設(shè)置最大空閑數(shù)
        config.setMaxIdle(8);
        // 設(shè)置最大等待時間
        config.setMaxWaitMillis(1000 * 100);
        // 在borrow一個jedis實例時，是否需要驗證，若為true，則所有jedis實例均是可用的
        config.setTestOnBorrow(true);
        jedisPool = new JedisPool(config, "192.168.3.27", 6379, 3000);
    }
    /**
     * 加鎖
     * @param lockName       鎖的key
     * @param acquireTimeout 獲取鎖的超時時間
     * @param timeout        鎖的超時時間
     * @return 鎖標識
     * Redis Setnx（SET if Not eXists） 命令在指定的 key 不存在時，為 key 設(shè)置指定的值。
     * 設(shè)置成功，返回 1 。 設(shè)置失敗，返回 0 。
     */
    public String lockWithTimeout(String lockName, long acquireTimeout, long timeout) {
        Jedis jedis = null;
        String retIdentifier = null;
        try {
            // 獲取連接
            jedis = jedisPool.getResource();
            // value值->隨機生成一個String
            String identifier = UUID.randomUUID().toString();
            // key值->即鎖名
            String lockKey = "lock:" + lockName;
            // 超時時間->上鎖后超過此時間則自動釋放鎖 毫秒轉(zhuǎn)成->秒
            int lockExpire = (int) (timeout / 1000);
            // 獲取鎖的超時時間->超過這個時間則放棄獲取鎖
            long end = System.currentTimeMillis() + acquireTimeout;
            while (System.currentTimeMillis() < end) { //在獲取鎖時間內(nèi)
                if (jedis.setnx(lockKey, identifier) == 1) {//關(guān)鍵:設(shè)置鎖
                    jedis.expire(lockKey, lockExpire);
                    // 返回value值，用于釋放鎖時間確認
                    retIdentifier = identifier;
                    return retIdentifier;
                }
                // ttl以秒為單位返回 key 的剩余過期時間，返回-1代表key沒有設(shè)置超時時間，為key設(shè)置一個超時時間
                if (jedis.ttl(lockKey) == -1) {
                    jedis.expire(lockKey, lockExpire);
                }
                try {
                    Thread.sleep(10);
                } catch (InterruptedException e) {
                    Thread.currentThread().interrupt();
                }
            }
        } catch (JedisException e) {
            e.printStackTrace();
        } finally {
            if (jedis != null) {
                jedis.close();
            }
        }
        return retIdentifier;
    }
    /**
     * 釋放鎖
     * @param lockName   鎖的key
     * @param identifier 釋放鎖的標識
     * @return
     */
    public boolean releaseLock(String lockName, String identifier) {
        Jedis jedis = null;
        String lockKey = "lock:" + lockName;
        boolean retFlag = false;
        try {
            jedis = jedisPool.getResource();
            while (true) {
                // 監(jiān)視lock，準備開始redis事務(wù)
                jedis.watch(lockKey);
                // 通過前面返回的value值判斷是不是該鎖，若是該鎖，則刪除，釋放鎖
                if (identifier.equals(jedis.get(lockKey))) {
                    Transaction transaction = jedis.multi();//開啟redis事務(wù)
                    transaction.del(lockKey);
                    List<Object> results = transaction.exec();//提交redis事務(wù)
                    if (results == null) {//提交失敗
                        continue;//繼續(xù)循環(huán)
                    }
                    retFlag = true;//提交成功
                }
                jedis.unwatch();//解除監(jiān)控
                break;
            }
        } catch (JedisException e) {
            e.printStackTrace();
        } finally {
            if (jedis != null) {
                jedis.close();
            }
        }
        return retFlag;
    }
}

import lombok.extern.slf4j.Slf4j;
@Slf4j
public class SkillService {
    final DistributedLock lock = new DistributedLock();
    public static final String LOCK_KEY = "lock_resource";
    int n = 500;
    /**
     * 線程業(yè)務(wù)方法
     */
    public void seckill() {
        // 返回鎖的value值，供釋放鎖時候進行判斷
        String identifier = lock.lockWithTimeout(LOCK_KEY, 5000, 1000);
        log.info("線程:"+Thread.currentThread().getName() + "獲得了鎖");
        log.info("剩余數(shù)量:{}",--n);
        lock.releaseLock(LOCK_KEY, identifier);
    }
}

<!--@Slf4j日志依賴組件-->
  <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
</dependency>

/**
 * @author swadian
 * @date 2022/3/4
 * @Version 1.0
 */
public class TestLock {
    public static void main(String[] args) {
        SkillService service = new SkillService();
        for (int i = 10; i < 60; i++) { //開50個線程
            SkillThread skillThread = new SkillThread(service, "skillThread->" + i);
            skillThread.start();
        }
    }
}
class SkillThread extends Thread {
    private SkillService skillService;
    public SkillThread(SkillService skillService, String skillThreadName) {
        super(skillThreadName);
        this.skillService = skillService;
    }
    @Override
    public void run() {
        skillService.seckill();
    }
}

@Slf4j
public class SkillService {
    final DistributedLock lock = new DistributedLock();
    public static final String LOCK_KEY = "lock_resource";
    int n = 500;
    /**
     * 線程業(yè)務(wù)方法
     */
    public void seckill() {
        // 返回鎖的value值，供釋放鎖時候進行判斷
        //String identifier = lock.lockWithTimeout(LOCK_KEY, 5000, 1000);
        log.info("線程:"+Thread.currentThread().getName() + "獲得了鎖");
        log.info("剩余數(shù)量:{}",--n);
        //lock.releaseLock(LOCK_KEY, identifier);
    }
}