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做拼团网站,哪些网站可以做海报热点的,wordpress 放视频,做网站公司融资多少钱1、手写 Redis 分布式锁#xff0c;包括上锁、解锁、自动续期。 此功能实现采用 Lua脚本实现#xff0c;Lua脚本可以保证原子性。 setnx可以实现分布式锁#xff0c;但是无法实现可重入锁#xff0c;所以用hset来代替setnx实现可重入的分布式锁。 – lock if redis.call…1、手写 Redis 分布式锁包括上锁、解锁、自动续期。 此功能实现采用 Lua脚本实现Lua脚本可以保证原子性。 setnx可以实现分布式锁但是无法实现可重入锁所以用hset来代替setnx实现可重入的分布式锁。 – lock if redis.call(exists,KEYS[1]) 0 or redis.call(hexists,KEYS[1],ARGV[1]) 1 thenredis.call(hincrby,KEYS[1],ARGV[1],1)redis.call(expire,KEYS[1],ARGV[2])return 1 elsereturn 0 end – unlock if redis.call(hexists,KEYS[1],ARGV[1]) 0 thenreturn nil elseif redis.call(hincrby,KEYS[1],ARGV[1],-1) 0 thenreturn redis.call(del,KEYS[1]) elsereturn 0 end – expire if redis.call(hexists,KEYS[1],ARGV[1]) 0 thenreturn redis.call(expire,KEYS[1],ARGV[2]) elsereturn 0 end 2、工具类如下 /*** author xxx* descpription: 自定义redis分布式锁* date 2024/7/24/ public class MyRedissonLua implements Lock {/** 加锁脚本/private static final String lockScript if redis.call(exists,KEYS[1]) 0 or redis.call(hexists,KEYS[1],ARGV[1]) 1 then redis.call(hincrby,KEYS[1],ARGV[1],1) redis.call(expire,KEYS[1],ARGV[2]) return 1 else return 0 end;/** 解锁脚本/private static final String unLockScript if redis.call(HEXISTS,KEYS[1],ARGV[1]) 0 then return nil elseif redis.call(HINCRBY,KEYS[1],ARGV[1],-1) 0 then return redis.call(del,KEYS[1]) else return 0 end;/** 续期脚本/private static final String expireScript if redis.call(HEXISTS,KEYS[1],ARGV[1]) 0 then return redis.call(EXPIRE,KEYS[1],ARGV[2]) else return 0 end;private StringRedisTemplate stringRedisTemplate;/** KEYS[1]/private String lockName;/** ARGV[1]/private String uuidValue;/** ARGV[2]*/private Long expireTime;public MyRedissonLua(StringRedisTemplate stringRedisTemplate, String lockName,String uuid) {this.stringRedisTemplate stringRedisTemplate;this.lockName lockName;this.uuidValue uuid : Thread.currentThread().getId();this.expireTime 30L;}Overridepublic void lock() {tryLock();}Overridepublic void unlock() {Long flag stringRedisTemplate.execute(new DefaultRedisScript(unLockScript, Long.class), Arrays.asList(lockName), uuidValue);System.out.println(unlock lockName: lockName \tuuidValue: uuidValue \t expireTime: expireTime);if(flag null) {throw new IllegalMonitorStateException(释放锁异常);}else {System.out.println(释放锁成功);}}Overridepublic boolean tryLock() {boolean result;try {result tryLock(-1L, TimeUnit.SECONDS);} catch (InterruptedException e) {throw new RuntimeException(e);}return result;}Overridepublic boolean tryLock(long time, TimeUnit unit) throws InterruptedException {if (time -1L){System.out.println(lockName: lockName \tuuidValue: uuidValue \t expireTime: expireTime);//可重入while (!stringRedisTemplate.execute(new DefaultRedisScript(lockScript, Boolean.class), Arrays.asList(lockName), uuidValue, String.valueOf(expireTime))){TimeUnit.MILLISECONDS.sleep(60);}//后台扫描程序检测key的ttl来实现续期reExpire();return true;}return false;}private void reExpire() {//每 10s 续期一次new Timer().schedule(new TimerTask(){Overridepublic void run() {System.out.println(Thread.currentThread().getName() 续期);if (stringRedisTemplate.execute(new DefaultRedisScript(lockScript, Boolean.class), Arrays.asList(lockName), uuidValue, String.valueOf(expireTime))){reExpire();}}},(this.expireTime * 1000) / 3);}Overridepublic void lockInterruptibly() {}Overridepublic Condition newCondition() {return null;} } 3、由于实现分布式锁的方式有很多故采用工厂模式 /*** author xxx* descpription: 工厂模式生产分布式锁* date 2024/7/24/ Component public class DistributedLockFactory {private String lockName;private String uuid;Resourceprivate StringRedisTemplate stringRedisTemplate;public DistributedLockFactory() {this.uuid IdUtil.simpleUUID();}public Lock getDistributedLock(String lockType){if (lockType null) {return null;}if (lockType.equals(REDIS)){lockName zzyyRedisLock;return new MyRedissonLua(stringRedisTemplate, lockName,uuid);} else if (lockType.equals(ZOOKEEPER)) {lockName zzyyZookeeperLock;//…Zookeeper版本的分布式锁return null;}return null;} } 4、业务代码 import cn.hutool.core.util.IdUtil; import com.coco.service.ICardService; import com.coco.utils.lua.DistributedLockFactory; import org.redisson.api.RedissonClient; import org.springframework.beans.factory.annotation.Value; import org.springframework.data.redis.core.StringRedisTemplate; import org.springframework.data.redis.core.script.DefaultRedisScript; import org.springframework.stereotype.Service;import javax.annotation.Resource; import java.util.Arrays; import java.util.Objects; import java.util.concurrent.TimeUnit; import java.util.concurrent.locks.Lock;/** author xxx* descpription: * date 2024/7/18/ Service public class ICardServiceImpl implements ICardService {Resourceprivate StringRedisTemplate stringRedisTemplate;private static final String KEY sale001;Value(${server.port})private String port;Resourceprivate RedissonClient redissonClient;/** 自定义的redis分布式锁/ // private Lock lock new MyRedissonLua(stringRedisTemplate, zzyyRedisLock);/** 通过工厂获取自定义的redis分布式锁/Resourceprivate DistributedLockFactory distributedLockFactory;Overridepublic String sale() {version7();return success;}private void version7() {Lock lock distributedLockFactory.getDistributedLock(REDIS);lock.lock();try{String countStr stringRedisTemplate.opsForValue().get(KEY);Integer count countStr null ? 0 : Integer.parseInt(countStr);if (count 0) {stringRedisTemplate.opsForValue().set(KEY,String.valueOf(–count));System.out.println(剩余库存为 stringRedisTemplate.opsForValue().get(KEY) 服务端口 port);//演示自动续期try {TimeUnit.SECONDS.sleep(120);} catch (InterruptedException e) {throw new RuntimeException(e);}}else {System.out.println(没有库存了);}}finally {lock.unlock();}}/** 可重入锁/private void version6() {Lock lock distributedLockFactory.getDistributedLock(REDIS);lock.lock();try{String countStr stringRedisTemplate.opsForValue().get(KEY);Integer count countStr null ? 0 : Integer.parseInt(countStr);if (count 0) {stringRedisTemplate.opsForValue().set(KEY,String.valueOf(–count));System.out.println(剩余库存为 stringRedisTemplate.opsForValue().get(KEY) 服务端口 port);//可重入testReEntry();}else {System.out.println(没有库存了);}}finally {lock.unlock();}}/** 可重入锁/private void testReEntry() {Lock lock distributedLockFactory.getDistributedLock(REDIS);lock.lock();try {System.out.println(再次获取锁);} finally {lock.unlock();}}/** 通过Lua脚本实现分布式锁解锁/private void version5() {String key zzyyRedisLock;String uuidValue IdUtil.simpleUUID() : Thread.currentThread().getId();//分布式锁(自旋)while (!stringRedisTemplate.opsForValue().setIfAbsent(key, uuidValue,10,TimeUnit.SECONDS)) {try {TimeUnit.MILLISECONDS.sleep(20);} catch (InterruptedException e) {throw new RuntimeException(e);}}try {String countStr stringRedisTemplate.opsForValue().get(KEY);Integer count countStr null ? 0 : Integer.parseInt(countStr);if (count 0) {stringRedisTemplate.opsForValue().set(KEY,String.valueOf(–count));System.out.println(剩余库存为 stringRedisTemplate.opsForValue().get(KEY) 服务端口 port);}else {System.out.println(没有库存了);}} finally {String script if redis.call(\get\,KEYS[1]) ARGV[1] then\n return redis.call(\del\,KEYS[1])\n else\n return 0\n end;stringRedisTemplate.execute(new DefaultRedisScript(script, Boolean.class),Arrays.asList(key), uuidValue);}}/** 添加判断防止解锁解的不是同一把锁/private void version4() {String key zzyyRedisLock;String uuidValue IdUtil.simpleUUID(): Thread.currentThread().getId();//分布式锁(自旋)while (!stringRedisTemplate.opsForValue().setIfAbsent(key, uuidValue,10,TimeUnit.SECONDS)) {try {TimeUnit.MILLISECONDS.sleep(20);} catch (InterruptedException e) {throw new RuntimeException(e);}}try {String countStr stringRedisTemplate.opsForValue().get(KEY);Integer count countStr null ? 0 : Integer.parseInt(countStr);if (count 0) {stringRedisTemplate.opsForValue().set(KEY,String.valueOf(–count));System.out.println(剩余库存为 stringRedisTemplate.opsForValue().get(KEY) 服务端口 port);}else {System.out.println(没有库存了);}} finally {if (Objects.equals(uuidValue, stringRedisTemplate.opsForValue().get(key))){stringRedisTemplate.delete(key);}}}/** 通过setnx实现redis分布式锁/private void version3() {String key zzyyRedisLock;String uuidValue IdUtil.simpleUUID(): Thread.currentThread().getId();//分布式锁Boolean flag stringRedisTemplate.opsForValue().setIfAbsent(key, uuidValue);if (flag) {try {String countStr stringRedisTemplate.opsForValue().get(KEY);Integer count countStr null ? 0 : Integer.parseInt(countStr);if (count 0) {stringRedisTemplate.opsForValue().set(KEY,String.valueOf(–count));System.out.println(剩余库存为 stringRedisTemplate.opsForValue().get(KEY) 服务端口 port);}else {System.out.println(没有库存了);}} finally {if (Objects.equals(uuidValue, stringRedisTemplate.opsForValue().get(key))){stringRedisTemplate.delete(key);}}}else {try {TimeUnit.MILLISECONDS.sleep(20);} catch (InterruptedException e) {throw new RuntimeException(e);}sale();}}/** juc的lock锁*/private void version2() { // lock.lock(); // try { // Integer count (Integer) redisTemplate.opsForValue().get(KEY); // if (count 0) { // redisTemplate.opsForValue().decrement(KEY); // System.out.println(剩余库存为 redisTemplate.opsForValue().get(KEY) 服务端口 port); // }else { // System.out.println(没有库存了); // } // } finally { // lock.unlock(); // }} }