基于Redis分布式鎖的實(shí)現(xiàn)代碼

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.Transaction;
import redis.clients.jedis.exceptions.JedisException;
import java.util.List;
import java.util.UUID;
/**
 * Created by liuyang on 2017/4/20.
 */
public class DistributedLock {
 private final JedisPool jedisPool;
 public DistributedLock(JedisPool jedisPool) {
 this.jedisPool = jedisPool;
 }
 /**
 * 加鎖
 * @param locaName 鎖的key
 * @param acquireTimeout 獲取超時(shí)時(shí)間
 * @param timeout 鎖的超時(shí)時(shí)間
 * @return 鎖標(biāo)識(shí)
 */
 public String lockWithTimeout(String locaName,
     long acquireTimeout, long timeout) {
 Jedis conn = null;
 String retIdentifier = null;
 try {
  // 獲取連接
  conn = jedisPool.getResource();
  // 隨機(jī)生成一個(gè)value
  String identifier = UUID.randomUUID().toString();
  // 鎖名，即key值
  String lockKey = "lock:" + locaName;
  // 超時(shí)時(shí)間，上鎖后超過(guò)此時(shí)間則自動(dòng)釋放鎖
  int lockExpire = (int)(timeout / 1000);
  // 獲取鎖的超時(shí)時(shí)間，超過(guò)這個(gè)時(shí)間則放棄獲取鎖
  long end = System.currentTimeMillis() + acquireTimeout;
  while (System.currentTimeMillis() < end) {
  if (conn.setnx(lockKey, identifier) == 1) {
   conn.expire(lockKey, lockExpire);
   // 返回value值，用于釋放鎖時(shí)間確認(rèn)
   retIdentifier = identifier;
   return retIdentifier;
  }
  // 返回-1代表key沒(méi)有設(shè)置超時(shí)時(shí)間，為key設(shè)置一個(gè)超時(shí)時(shí)間
  if (conn.ttl(lockKey) == -1) {
   conn.expire(lockKey, lockExpire);
  }
  try {
   Thread.sleep(10);
  } catch (InterruptedException e) {
   Thread.currentThread().interrupt();
  }
  }
 } catch (JedisException e) {
  e.printStackTrace();
 } finally {
  if (conn != null) {
  conn.close();
  }
 }
 return retIdentifier;
 }
 /**
 * 釋放鎖
 * @param lockName 鎖的key
 * @param identifier 釋放鎖的標(biāo)識(shí)
 * @return
 */
 public boolean releaseLock(String lockName, String identifier) {
 Jedis conn = null;
 String lockKey = "lock:" + lockName;
 boolean retFlag = false;
 try {
  conn = jedisPool.getResource();
  while (true) {
  // 監(jiān)視lock，準(zhǔn)備開(kāi)始事務(wù)
  conn.watch(lockKey);
  // 通過(guò)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(conn.get(lockKey))) {
   Transaction transaction = conn.multi();
   transaction.del(lockKey);
   List<Object> results = transaction.exec();
   if (results == null) {
   continue;
   }
   retFlag = true;
  }
  conn.unwatch();
  break;
  }
 } catch (JedisException e) {
  e.printStackTrace();
 } finally {
  if (conn != null) {
  conn.close();
  }
 }
 return retFlag;
 }
}

import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

/**
 * Created by liuyang on 2017/4/20.
 */
public class Service {
 private static JedisPool pool = null;
 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(shí)間
 config.setMaxWaitMillis(1000 * 100);
 // 在borrow一個(gè)jedis實(shí)例時(shí)，是否需要驗(yàn)證，若為true，則所有jedis實(shí)例均是可用的
 config.setTestOnBorrow(true);
 pool = new JedisPool(config, "127.0.0.1", 6379, 3000);
 }
 DistributedLock lock = new DistributedLock(pool);
 int n = 500;
 public void seckill() {
 // 返回鎖的value值，供釋放鎖時(shí)候進(jìn)行判斷
 String indentifier = lock.lockWithTimeout("resource", 5000, 1000);
 System.out.println(Thread.currentThread().getName() + "獲得了鎖");
 System.out.println(--n);
 lock.releaseLock("resource", indentifier);
 }
}
// 模擬線(xiàn)程進(jìn)行秒殺服務(wù)

public class ThreadA extends Thread {
 private Service service;
 public ThreadA(Service service) {
 this.service = service;
 }
 @Override
 public void run() {
 service.seckill();
 }
}

public class Test {
 public static void main(String[] args) {
 Service service = new Service();
 for (int i = 0; i < 50; i++) {
  ThreadA threadA = new ThreadA(service);
  threadA.start();
 }
 }
}

public void seckill() {
 // 返回鎖的value值，供釋放鎖時(shí)候進(jìn)行判斷
 //String indentifier = lock.lockWithTimeout("resource", 5000, 1000);
 System.out.println(Thread.currentThread().getName() + "獲得了鎖");
 System.out.println(--n);
 //lock.releaseLock("resource", indentifier);
}