java基于spring.redisTemplate实现分布式锁工具类 Java工具类

### 工具类

```
import javafx.util.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.redis.core.BoundValueOperations;
import org.springframework.data.redis.core.StringRedisTemplate;

import java.util.concurrent.TimeUnit;
import java.util.function.Supplier;

public class RedisLock {
    private static final Logger LOG = LoggerFactory.getLogger(RedisLock.class);
    private static final String LOCKED = "LOCKED";  // 存储到redis中的锁标志

private volatile boolean isLocked = false;
    private StringRedisTemplate redisTemplate;
    private String key;

private TimeUnit lockTimeoutAndExpireTimeUnit = TimeUnit.SECONDS;
    private int getLockTimeout = 10;    // 请求锁的超时时间
    private int lockExpire = 30;        // 获取到锁后，设置锁过期时间

private int sleepMillis = 100;      // 每次请求失败休眠时间（毫秒）

/**
     * @param redisTemplate                Redis管理模板
     * @param key                          锁定key
     * @param lockTimeoutAndExpireTimeUnit [获取锁超时/锁失效]对应的TimeUnit（默认：TimeUnit.SECONDS）
     * @param getLockTimeout               锁过期时间（避免程序问题而一直持有锁）
     * @param lockExpire                   请求锁超时时间
     * @param sleepMillis                  每次请求锁失败最少休眠时间（毫秒）
     */
    public RedisLock(StringRedisTemplate redisTemplate, String key, TimeUnit lockTimeoutAndExpireTimeUnit, int getLockTimeout, int lockExpire, int sleepMillis) {
        if (redisTemplate == null) {
            throw new RuntimeException("redis锁StringRedisTemplate不能为null");
        }
        if (key == null || "".equals(key.trim())) {
            throw new RuntimeException("redis锁的key不能为空");
        }
        this.redisTemplate = redisTemplate;
        this.key = key;

if (lockTimeoutAndExpireTimeUnit != null) {
            this.lockTimeoutAndExpireTimeUnit = lockTimeoutAndExpireTimeUnit;
        }
        if (getLockTimeout > 0) {
            this.getLockTimeout = getLockTimeout;
        }
        if (lockExpire > 0) {
            this.lockExpire = lockExpire;
        }
        if (sleepMillis > 0) {
            this.sleepMillis = sleepMillis;
        }
    }

public RedisLock(StringRedisTemplate redisTemplate, String key, int getLockTimeout, int lockExpire, int sleepMillis) {
        this(redisTemplate, key, null, getLockTimeout, lockExpire, sleepMillis);
    }

public RedisLock(StringRedisTemplate redisTemplate, String key, TimeUnit lockTimeoutAndExpireTimeUnit, int getLockTimeout, int lockExpire) {
        this(redisTemplate, key, lockTimeoutAndExpireTimeUnit, getLockTimeout, lockExpire, 0);
    }

public RedisLock(StringRedisTemplate redisTemplate, String key, int getLockTimeout, int lockExpire) {
        this(redisTemplate, key, null, getLockTimeout, lockExpire, 0);
    }

public RedisLock(StringRedisTemplate redisTemplate, String key, int sleepMillis) {
        this(redisTemplate, key, null, 0, 0, sleepMillis);
    }

public RedisLock(StringRedisTemplate redisTemplate, String key) {
        this(redisTemplate, key, null, 0, 0, 0);
    }

public static <T> Pair<Boolean, T> lockedWork(RedisLock redisLock, Supplier<T> worker) {
        return lockedWork(redisLock, 0, 0, worker);
    }

/**
     * @param redisLock          分布式锁对象
     * @param addSleepTimeMillis 每次获取锁失败后叠加等待时间
     * @param maxSleepTimeMillis 叠加等待时间的最大时间，超过则不再叠加
     * @param worker             获取到锁后的业务处理函数
     * @param <T>
     *
     * @return
     */
    public static <T> Pair<Boolean, T> lockedWork(RedisLock redisLock, int addSleepTimeMillis, int maxSleepTimeMillis, Supplier<T> worker) {
        if (redisLock == null || worker == null) {
            throw new RuntimeException("本地锁或redisLock对象或锁内程序不能为空");
        }
        if (!redisLock.lock(addSleepTimeMillis, maxSleepTimeMillis)) {
            LOG.error(String.format("未获取到锁，任务取消，锁：%s", redisLock.key));
            return new Pair<>(false, null);
        }
        LOG.warn(String.format("已获取到锁，开始执行锁内程序，锁：%s", redisLock.key));
        try {
            return new Pair<>(true, worker.get());
        } finally {
            redisLock.unlock();
            LOG.warn(String.format("释放锁：%s", redisLock.key));
        }
    }

public static void main(String[] args) {
        Pair<Boolean, String> result = RedisLock.lockedWork(
                new RedisLock(null, "lockKey"),
                () -> {
                    // 锁内程序
                    return "我是锁内程序执行结果";
                }
        );
        if (result.getKey()) {
            System.out.println("锁内程序成功调用，并返回数据：" + result.getValue());
        } else {
            System.out.println("未获取到锁");
        }
    }

private boolean lock() {
        return this.lock(0, 0);
    }

/**
     * 获取锁
     *
     * @param addSleepTimeMillis 递增睡眠时间
     * @param maxSleepTimeMillis 最大睡眠时间
     *
     * @return
     */
    private boolean lock(int addSleepTimeMillis, int maxSleepTimeMillis) {
        if (maxSleepTimeMillis < sleepMillis) maxSleepTimeMillis = sleepMillis;
        if (addSleepTimeMillis < 0) addSleepTimeMillis = 0;

BoundValueOperations<String, String> ops = this.redisTemplate.boundValueOps(key);
        long timeout = TimeUnit.MILLISECONDS.convert(this.getLockTimeout, lockTimeoutAndExpireTimeUnit);
        long expire = TimeUnit.MILLISECONDS.convert(this.lockExpire, lockTimeoutAndExpireTimeUnit);
        long startTime = System.currentTimeMillis();

int currSleepMillis = sleepMillis;
        while ((System.currentTimeMillis() - startTime) < timeout) {
            try {
                if (ops.setIfAbsent(LOCKED)) {
                    this.redisTemplate.expire(key, expire, TimeUnit.MILLISECONDS);
                    this.isLocked = true;
                    break;
                } else if (ops.getExpire() == -1L) {
                    this.redisTemplate.expire(key, expire, TimeUnit.MILLISECONDS);
                    LOG.error("检测到已存在的锁未设置失效时间，为其设置失效时间，key：" + key);
                }
                if (currSleepMillis > maxSleepTimeMillis) currSleepMillis = maxSleepTimeMillis;
                LOG.warn(String.format("未获取到锁，%s，休眠：%s毫秒，key：%s", Thread.currentThread(), currSleepMillis, key));

TimeUnit.MILLISECONDS.sleep(currSleepMillis);
                currSleepMillis = currSleepMillis + addSleepTimeMillis;
            } catch (Exception e) {
                LOG.error("", e);
            }
        }
        return this.isLocked;
    }

private void unlock() {
        if (this.isLocked) {
            this.redisTemplate.delete(key);
        }
    }
}
```

vanki

在面对这些强敌之前...一定要先将眼前敌人逐个打败吧。

创建： 2018-09-14 01:00:14

更新： 2020-08-20 14:51:13

java基于spring.redisTemplate实现分布式锁工具类 Java工具类

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