• java分布式锁

    文章目录

    1.基于数据库实现分布式锁

    数据库实现分布式锁方式比较多，如悲观锁(查询时增加for update)、乐观锁(通过version字段)、增加一个表记录锁信息等。因为依赖于数据库，比较好理解，但是也存在一些问题。
    如悲观锁在某些情况下可能会锁表而不是锁行，乐观锁可能需要多次重试，以及操作数据库的性能开销等等，所以基于数据库的分布式锁不做过多研究，因为我看来基本上不会用到。

    2. 基于缓存（redis）实现分布式锁

    2.1 基于redis实现的分布式锁

    2.1.1 配置类

    package com.mashibing.lock;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

@Configuration
@PropertySource("classpath:application.properties")
public class RedisConfig {
    @Value("${redis.host}")
    private String host;

    @Value("${redis.port}")
    private int port;

    @Value("${redis.timeout}")
    private int timeout;

    @Value("${redis.maxIdle}")
    private int maxIdle;

    @Value("${redis.maxWaitMillis}")
    private int maxWaitMillis;

    @Value("${redis.blockWhenExhausted}")
    private Boolean blockWhenExhausted;

    @Value("${redis.JmxEnabled}")
    private Boolean JmxEnabled;

    @Bean
    public JedisPool jedisPoolFactory() {
        JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
        jedisPoolConfig.setMaxIdle(maxIdle);
        jedisPoolConfig.setMaxWaitMillis(maxWaitMillis);
        // 连接耗尽时是否阻塞, false报异常,true阻塞直到超时, 默认true
        jedisPoolConfig.setBlockWhenExhausted(blockWhenExhausted);
        // 是否启用pool的jmx管理功能, 默认true
        jedisPoolConfig.setJmxEnabled(JmxEnabled);
        JedisPool jedisPool = new JedisPool(jedisPoolConfig, host, port, timeout);
        return jedisPool;
    }
}


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    2.1.2 分布式锁实现

    package com.mashibing.lock;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.params.SetParams;

import java.util.Arrays;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/**
 * 分布式锁的实现
 */
@Component
public class RedisDistLock implements Lock {

    private final static int LOCK_TIME = 5*1000;//失效时间
    private final static String RS_DISTLOCK_NS = "tdln:"; //加锁的key的前缀
    /*
     if redis.call('get',KEYS[1])==ARGV[1] then
        return redis.call('del', KEYS[1])
    else return 0 end
     */
    //释放锁的时候，确保原子。lua脚本：确保  释放锁的线程就是加锁的线程，不能被线程的线程无脑调用释放
    private final static String RELEASE_LOCK_LUA =
            "if redis.call('get',KEYS[1])==ARGV[1] then\n" +
                    "        return redis.call('del', KEYS[1])\n" +
                    "    else return 0 end";
    /*保存每个线程的独有的ID值*/
    private ThreadLocal<String> lockerId = new ThreadLocal<>();

    /*解决锁的重入*/
    private Thread ownerThread;
    private String lockName = "lock";

    @Autowired
    private JedisPool jedisPool;

    public String getLockName() {
        return lockName;
    }

    public void setLockName(String lockName) {
        this.lockName = lockName;
    }

    public Thread getOwnerThread() {
        return ownerThread;
    }

    public void setOwnerThread(Thread ownerThread) {//加锁成功，就会把抢到锁的线程进行保存
        this.ownerThread = ownerThread;
    }

    @Override
    public void lock() { //redis的分布式锁
        while(!tryLock()){
            try {
                Thread.sleep(100); //每隔100ms 都会去尝试加锁
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void lockInterruptibly() throws InterruptedException {
        throw new UnsupportedOperationException("不支持可中断获取锁！");
    }

    @Override
    public boolean tryLock() {
        Thread t = Thread.currentThread();
        if(ownerThread==t){/*说明本线程持有锁*/
            return true;
        }else if(ownerThread!=null){/*本进程里有其他线程持有分布式锁*/
            return false;
        }
        Jedis jedis = jedisPool.getResource();
        try {
            String id = UUID.randomUUID().toString();
            SetParams params = new SetParams();
            params.px(LOCK_TIME);
            params.nx();
            synchronized (this){/*线程们，本地抢锁*/
                if((ownerThread==null)&&
                "OK".equals(jedis.set(RS_DISTLOCK_NS+lockName,id,params))){
                    lockerId.set(id);
                    setOwnerThread(t);
                    return true;
                }else{
                    return false;
                }
            }
        } catch (Exception e) {
            throw new RuntimeException("分布式锁尝试加锁失败！");
        } finally {
            jedis.close();
        }
    }

    @Override
    public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
        throw new UnsupportedOperationException("不支持等待尝试获取锁！");
    }

    @Override
    public void unlock() {
        if(ownerThread!=Thread.currentThread()) {
            throw new RuntimeException("试图释放无所有权的锁！");
        }
        Jedis jedis = null;
        try {
            jedis = jedisPool.getResource();
            Long result = (Long)jedis.eval(RELEASE_LOCK_LUA,
                    Arrays.asList(RS_DISTLOCK_NS+lockName),
                    Arrays.asList(lockerId.get()));
            if(result.longValue()!=0L){
                System.out.println("Redis上的锁已释放！");
            }else{
                System.out.println("Redis上的锁释放失败！");
            }
        } catch (Exception e) {
            throw new RuntimeException("释放锁失败！",e);
        } finally {
            if(jedis!=null) jedis.close();
            lockerId.remove();
            setOwnerThread(null);
            System.out.println("本地锁所有权已释放！");
        }
    }

    @Override
    public Condition newCondition() {
        throw new UnsupportedOperationException("不支持等待通知操作！");
    }

}


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    这样实现的分布式锁会产生的问题是，当业务代码消耗的时间大于redis的过期时间，业务代码还没执行完，锁已经释放

    解决方案:加入看门狗，就是判断业务代码是否执行完，没执行完， 在redis失效前100毫秒，给redis续期

    2.1.3 看门狗具体实现

    ItemVo

    package com.mashibing.lock.rdl;

import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

/**
 *
 *类说明：存放到延迟队列的元素，比标准的delay的实现要提前一点时间
 */
public class ItemVo<T> implements Delayed{

    /*到期时刻  20:00:35,234*/
    private long activeTime;
    /*业务数据，泛型*/
    private T data;

	/*传入的数值代表过期的时长，单位毫秒，需要乘1000转换为毫秒和到期时间
	* 同时提前100毫秒续期,具体的时间可以自己决定*/
	public ItemVo(long expirationTime, T data) {
		super();
		this.activeTime = expirationTime+System.currentTimeMillis()-100;
		this.data = data;
	}

	public long getActiveTime() {
		return activeTime;
	}

	public T getData() {
		return data;
	}
	
	/**
	 * 返回元素到激活时刻的剩余时长
	 */
	public long getDelay(TimeUnit unit) {
		long d = unit.convert(this.activeTime
						- System.currentTimeMillis(),unit);
		return d;
	}

	/**按剩余时长排序*/
	public int compareTo(Delayed o) {
        long d = (getDelay(TimeUnit.MILLISECONDS)
				-o.getDelay(TimeUnit.MILLISECONDS));
        if (d==0){
        	return 0;
		}else{
        	if (d<0){
        		return -1;
			}else{
        		return  1;
			}
		}
	}

}

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    LockItem

    package com.mashibing.lock.rdl;
/**
 *
 *类说明：Redis的key-value结构
 */
public class LockItem {
    private final String key;
    private final String value;

    public LockItem(String key, String value) {
        this.key = key;
        this.value = value;
    }

    public String getKey() {
        return key;
    }

    public String getValue() {
        return value;
    }
}

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    RedisDistLockWithDog

    package com.mashibing.lock.rdl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.params.SetParams;

import javax.annotation.PreDestroy;
import java.util.Arrays;
import java.util.UUID;
import java.util.concurrent.DelayQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

/**
 * 分布式锁，附带看门狗线程的实现:加锁，保持锁1秒
 */
@Component
public class RedisDistLockWithDog implements Lock {

    private final static int LOCK_TIME = 1*1000;
    private final static String LOCK_TIME_STR = String.valueOf(LOCK_TIME);
    private final static String RS_DISTLOCK_NS = "tdln2:";
    /*
     if redis.call('get',KEYS[1])==ARGV[1] then
        return redis.call('del', KEYS[1])
    else return 0 end
     */
    private final static String RELEASE_LOCK_LUA =
            "if redis.call('get',KEYS[1])==ARGV[1] then\n" +
                    "        return redis.call('del', KEYS[1])\n" +
                    "    else return 0 end";
    /*还有并发问题，考虑ThreadLocal*/
    private ThreadLocal<String> lockerId = new ThreadLocal<>();

    private Thread ownerThread;
    private String lockName = "lock";

    @Autowired
    private JedisPool jedisPool;

    public String getLockName() {
        return lockName;
    }

    public void setLockName(String lockName) {
        this.lockName = lockName;
    }

    public Thread getOwnerThread() {
        return ownerThread;
    }

    public void setOwnerThread(Thread ownerThread) {
        this.ownerThread = ownerThread;
    }

    @Override
    public void lock() {
        while(!tryLock()){
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    @Override
    public void lockInterruptibly() throws InterruptedException {
        throw new UnsupportedOperationException("不支持可中断获取锁！");
    }

    @Override
    public boolean tryLock() {
        Thread t=Thread.currentThread();
        /*说明本线程正在持有锁*/
        if(ownerThread==t) {
            return true;
        }else if(ownerThread!=null){/*说明本进程中有别的线程正在持有分布式锁*/
            return false;
        }
        Jedis jedis = null;
        try {
            jedis = jedisPool.getResource();
            /*每一个锁的持有人都分配一个唯一的id，也可采用snowflake算法*/
            String id = UUID.randomUUID().toString();

            SetParams params = new SetParams();
            params.px(LOCK_TIME); //加锁时间1s
            params.nx();
            synchronized (this){
                if ((ownerThread==null)&&
                        "OK".equals(jedis.set(RS_DISTLOCK_NS+lockName,id,params))) {
                    lockerId.set(id);
                    setOwnerThread(t);
                    if(expireThread == null){//看门狗线程启动
                        expireThread = new Thread(new ExpireTask(),"expireThread");
                        expireThread.setDaemon(true);
                        expireThread.start();
                    }
                    //往延迟阻塞队列中加入元素（让看门口可以在过期之前一点点的时间去做锁的续期）
                    delayDog.add(new ItemVo<>((int)LOCK_TIME,new LockItem(lockName,id)));
                    System.out.println(Thread.currentThread().getName()+"已获得锁----");
                    return true;
                }else{
                    System.out.println(Thread.currentThread().getName()+"无法获得锁----");
                    return false;
                }
            }
        } catch (Exception e) {
            throw new RuntimeException("分布式锁尝试加锁失败！",e);
        } finally {
            jedis.close();
        }
    }

    @Override
    public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
        throw new UnsupportedOperationException("不支持等待尝试获取锁！");
    }

    @Override
    public void unlock() {
        if(ownerThread!=Thread.currentThread()) {
            throw new RuntimeException("试图释放无所有权的锁！");
        }
        Jedis jedis = null;
        try {
            jedis = jedisPool.getResource();
            Long result = (Long)jedis.eval(RELEASE_LOCK_LUA,
                    Arrays.asList(RS_DISTLOCK_NS+lockName),
                    Arrays.asList(lockerId.get()));
            System.out.println(result);
            if(result.longValue()!=0L){
                System.out.println("Redis上的锁已释放！");
            }else{
                System.out.println("Redis上的锁释放失败！");
            }
        } catch (Exception e) {
            throw new RuntimeException("释放锁失败！",e);
        } finally {
            if(jedis!=null) jedis.close();
            lockerId.remove();
            setOwnerThread(null);
        }
    }

    @Override
    public Condition newCondition() {
        throw new UnsupportedOperationException("不支持等待通知操作！");
    }

    /*看门狗线程*/
    private Thread expireThread;
    //通过delayDog 避免无谓的轮询，减少看门狗线程的轮序次数   阻塞延迟队列   刷1  没有刷2
    private static DelayQueue<ItemVo<LockItem>> delayDog = new DelayQueue<>();
    //续锁逻辑：判断是持有锁的线程才能续锁
    private final static String DELAY_LOCK_LUA =
            "if redis.call('get',KEYS[1])==ARGV[1] then\n" +
                    "        return redis.call('pexpire', KEYS[1],ARGV[2])\n" +
                    "    else return 0 end";
    private class ExpireTask implements Runnable{

        @Override
        public void run() {
            System.out.println("看门狗线程已启动......");
            while(!Thread.currentThread().isInterrupted()) {
                try {
                    LockItem lockItem = delayDog.take().getData();//只有元素快到期了才能take到  0.9s
                    Jedis jedis = null;
                    try {
                        jedis = jedisPool.getResource();
                        Long result = (Long)jedis.eval(DELAY_LOCK_LUA,
                                Arrays.asList(RS_DISTLOCK_NS+lockItem.getKey ()),
                                Arrays.asList(lockItem.getValue(),LOCK_TIME_STR));
                        if(result.longValue()==0L){
                            System.out.println("Redis上的锁已释放，无需续期！");
                        }else{
                            delayDog.add(new ItemVo<>((int)LOCK_TIME,
                                    new LockItem(lockItem.getKey(),lockItem.getValue())));
                            System.out.println("Redis上的锁已续期:"+LOCK_TIME);
                        }
                    } catch (Exception e) {
                        throw new RuntimeException("锁续期失败！",e);
                    } finally {
                        if(jedis!=null) jedis.close();
                    }
                } catch (InterruptedException e) {
                    System.out.println("看门狗线程被中断");
                    break;
                }
            }
            System.out.println("看门狗线程准备关闭......");
        }
    }

//    @PostConstruct
//    public void initExpireThread(){
//
//    }

    @PreDestroy
    public void closeExpireThread(){
        if(null!=expireThread){
            expireThread.interrupt();
        }
    }
}


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    2.2 基于Redission实现

    2.2.1导入redssion包

       <dependency>
            <groupId>org.redissongroupId>
            <artifactId>redissonartifactId>
            <version>3.12.3version>
        dependency>

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    2.1.2 创建配置类

    package com.mashibing.redission;

import org.redisson.Redisson;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MyRedissionConfig {
    @Value("${redis.host}")
    private String host;
    @Value("${redis.port}")
    private String port;
    @Bean(destroyMethod = "shutdown")
    public RedissonClient redisson(){
        //1、创建配置
        Config config = new Config();
        config.useSingleServer().setAddress("redis://"+host+":"+port);
        //2、根据config配置创建出RedissonClient的实例
        RedissonClient redissonClient= Redisson.create(config);
        return redissonClient;
    }
}

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    2.1.3 实际业务代码的实现

    package com.mashibing.service;

import com.mashibing.dao.ShopGoodsMapper;
import com.mashibing.dao.shopGoodsUniqueMapper;
import com.mashibing.lock.RedisDistLock;
import com.mashibing.model.ShopGoods;
import com.mashibing.model.shopGoodsUnique;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.locks.InterProcessLock;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.concurrent.TimeUnit;



@Service
@Transactional
public class GoodsServiceRedisImpl {

    private static final Logger logger = LoggerFactory.getLogger(GoodsServiceRedisImpl.class);



	@Autowired
	private ShopGoodsMapper shopGoodsMapper;

    @Autowired
    private shopGoodsUniqueMapper shopGoodsUniqueMapper;
    //Redis分布式锁
    @Autowired
    private RedisDistLock redisDistLock;
    @Autowired
    private RedissonClient redissonClient;
    //Zookeeper分布式锁
    @Autowired
    private CuratorFramework  curatorFramework;
//    static InterProcessLock lock ;


        //多个应用，分布式部署，这里需要使用分布式锁类解决问题
    public  int updateGoods(long orderId, long goodsId, int goodsNumber){
//        synchronized (this){
//            if(lock ==null){ //多线程安全问题
//                lock =  new InterProcessMutex(curatorFramework,"/locks2");
//            }
//        }

        int ireturn =-1;
        RLock lock = redissonClient.getLock("RD-LOCK");
        lock.lock(1, TimeUnit.SECONDS);
        try{
            //redisson实现分布式锁

//            redisDistLock.lock();
//           zookeeper实现的分布式锁（临时、序号节点，包括监听机制）
//            if(lock.acquire(5, TimeUnit.SECONDS)){
                ShopGoods shopGoods =shopGoodsMapper.selectByPrimaryKey(goodsId);
                Integer goodnumber = shopGoods.getGoodsNumber()-goodsNumber;
                shopGoods.setGoodsNumber(goodnumber);
                if(shopGoodsMapper.updateByPrimaryKey(shopGoods)>=0){
                    //logger.info("修改库存成功：[" + orderId + "]");
                    ireturn =1;
                }else{
                    logger.error("修改库存失败：[" + orderId + "]");
                    ireturn =-1;
                }
//            }else {
//                logger.error("修改库存失败：[拿不到zk分布式锁]");
//                ireturn =-1;
//            }
        }catch (Exception e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
//            redisDistLock.unlock();
//            try {
//                lock.release(); //释放锁
//            } catch (Exception e) {
//                e.printStackTrace();
//            }
            return ireturn;
        }
    }

    //回退-扣减库存
    public  int CancelupdateGoods(long orderId, long goodsId, int goodsNumber){
        try {
            //去重表中有，才能证明是插入了，所以要回退
            shopGoodsUnique shopGoodsUnique = new shopGoodsUnique();
            shopGoodsUnique.setOrderId(orderId);
            shopGoodsUniqueMapper.insert(shopGoodsUnique);
        }catch (Exception e) {
            ShopGoods shopGoods =shopGoodsMapper.selectByPrimaryKey(goodsId);
            Integer goodnumber = shopGoods.getGoodsNumber()+goodsNumber;
            shopGoods.setGoodsNumber(goodnumber);
            if(shopGoodsMapper.updateByPrimaryKey(shopGoods)>=0){
                //logger.info("修改库存成功：[" + orderId + "]");
                return 1;
            }else{
                logger.error("回退库存失败：[" + orderId + "]");
                return -1;
            }
        }
      return 1;
    }

}

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    3. 基于Zookeeper实现分布式锁

    原理：创建临时节点(就是基于客户端与服务端的session,断开就会删除),第一个线程进来获得锁，第二个线程利用watch机制监听第一个线程，第一个线程结束就获得锁，以此类推

    3.1代码实现

    3.1.1 导包

      
        <dependency>
            <groupId>org.apache.curatorgroupId>
            <artifactId>curator-frameworkartifactId>
            <version>5.2.1version>
        dependency>
        <dependency>
            <groupId>org.apache.curatorgroupId>
            <artifactId>curator-recipesartifactId>
            <version>5.2.1version>
        dependency>
        
        <dependency>
            <groupId>org.apache.zookeepergroupId>
            <artifactId>zookeeperartifactId>
            <version>3.8.0version>
        dependency>

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    3.1.2 ZK配置类

    package com.mashibing.lock.zk;

import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class CuratorConfig {
    @Autowired
    WrapperZK wrapperZK;
    //这里返回一个zk的客户端的bean
    @Bean
    public CuratorFramework curatorFramework(){
        RetryPolicy retryPolicy = new ExponentialBackoffRetry(wrapperZK.getElapsedTimeMs(), wrapperZK.getRetryCount());
        CuratorFramework client= CuratorFrameworkFactory.newClient(wrapperZK.getConnectString(),
                wrapperZK.getSessionTimeoutMs(),
                wrapperZK.getConnectionTimeoutMs(),
                retryPolicy);
        client.start();
        return client;
    }
}


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    3.1.3 实体类

    package com.mashibing.lock.zk;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Data
@Component
@ConfigurationProperties(prefix = "curator")
public class WrapperZK {
    private int retryCount;
    private int elapsedTimeMs;
    private String connectString;
    private int sessionTimeoutMs;
    private int connectionTimeoutMs;
}


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    3.1.4 实际业务代码实现

    package com.mashibing.service;

import com.mashibing.dao.ShopGoodsMapper;
import com.mashibing.dao.shopGoodsUniqueMapper;
import com.mashibing.lock.RedisDistLock;
import com.mashibing.lock.rdl.RedisDistLockWithDog;
import com.mashibing.model.ShopGoods;
import com.mashibing.model.shopGoodsUnique;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.recipes.locks.InterProcessLock;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.concurrent.TimeUnit;


/**
 *@author 李瑾老师
 *
 *类说明：订单相关的服务
 */
@Service
@Transactional
public class GoodsServiceImpl {

    private static final Logger logger = LoggerFactory.getLogger(GoodsServiceImpl.class);



	@Autowired
	private ShopGoodsMapper shopGoodsMapper;

    @Autowired
    private shopGoodsUniqueMapper shopGoodsUniqueMapper;
    //Redis分布式锁
    @Autowired
    private RedisDistLock redisDistLock;

    //Zookeeper分布式锁
    @Autowired
    private CuratorFramework  curatorFramework;
    static InterProcessLock lock ;


        //多个应用，分布式部署，这里需要使用分布式锁类解决问题
    public  int updateGoods(long orderId, long goodsId, int goodsNumber){
        synchronized (this){
            if(lock ==null){ //多线程安全问题
                lock =  new InterProcessMutex(curatorFramework,"/locks2");
            }
        }
        int ireturn =-1;
        try{
            //redisDistLock.lock();
           //zookeeper实现的分布式锁（临时、序号节点，包括监听机制）
            if(lock.acquire(5, TimeUnit.SECONDS)){
                ShopGoods shopGoods =shopGoodsMapper.selectByPrimaryKey(goodsId);
                Integer goodnumber = shopGoods.getGoodsNumber()-goodsNumber;
                shopGoods.setGoodsNumber(goodnumber);
                if(shopGoodsMapper.updateByPrimaryKey(shopGoods)>=0){
                    //logger.info("修改库存成功：[" + orderId + "]");
                    ireturn =1;
                }else{
                    logger.error("修改库存失败：[" + orderId + "]");
                    ireturn =-1;
                }
            }else {
                logger.error("修改库存失败：[拿不到zk分布式锁]");
                ireturn =-1;
            }
        }catch (Exception e) {
            e.printStackTrace();
        }finally {
            //redisDistLock.unlock();
            try {
                lock.release(); //释放锁
            } catch (Exception e) {
                e.printStackTrace();
            }
            return ireturn;
        }
    }

    //回退-扣减库存
    public  int CancelupdateGoods(long orderId, long goodsId, int goodsNumber){
        try {
            //去重表中有，才能证明是插入了，所以要回退
            shopGoodsUnique shopGoodsUnique = new shopGoodsUnique();
            shopGoodsUnique.setOrderId(orderId);
            shopGoodsUniqueMapper.insert(shopGoodsUnique);
        }catch (Exception e) {
            ShopGoods shopGoods =shopGoodsMapper.selectByPrimaryKey(goodsId);
            Integer goodnumber = shopGoods.getGoodsNumber()+goodsNumber;
            shopGoods.setGoodsNumber(goodnumber);
            if(shopGoodsMapper.updateByPrimaryKey(shopGoods)>=0){
                //logger.info("修改库存成功：[" + orderId + "]");
                return 1;
            }else{
                logger.error("回退库存失败：[" + orderId + "]");
                return -1;
            }
        }
      return 1;
    }


}


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  • 原文地址：https://blog.csdn.net/yaoxie1534/article/details/128197131