SpringBoot集成Redisson实现分布式锁的方法示例

上篇 《SpringBoot 集成 redis 分布式锁优化》对死锁的问题进行了优化，今天介绍的是 redis 官方推荐使用的 Redisson ，Redisson 架设在 redis 基础上的 Java 驻内存数据网格（In-Memory Data Grid），基于NIO的 Netty 框架上，利用了 redis 键值数据库。功能非常强大，解决了很多分布式架构中的问题。

Github的wiki地址： https://github.com/redisson/redisson/wiki

官方文档： https://github.com/redisson/redisson/wiki/目录

项目代码结构图：

导入依赖

<dependency>
	<groupId>org.redisson</groupId>
	<artifactId>redisson</artifactId>
	<version>3.8.0</version>
</dependency>

属性配置

在 application.properites 资源文件中添加单机&哨兵相关配置

server.port=3000

# redisson lock 单机模式
redisson.address=redis://127.0.0.1:6379
redisson.password=

#哨兵模式
#redisson.master-name= master
#redisson.password=
#redisson.sentinel-addresses=10.47.91.83:26379,10.47.91.83:26380,10.47.91.83:26381

注意：

这里如果不加 redis:// 前缀会报 URI 构建错误

Caused by: java.net.URISyntaxException: Illegal character in scheme name at index 0

更多的配置信息可以去官网查看

定义Lock的接口定义类

package com.tuhu.thirdsample.service;

import org.redisson.api.RLock;
import java.util.concurrent.TimeUnit;
/**
 * @author chendesheng
 * @create 2019/10/12 10:48
 */
public interface DistributedLocker {

 RLock lock(String lockKey);

 RLock lock(String lockKey, int timeout);

 RLock lock(String lockKey, TimeUnit unit, int timeout);

 boolean tryLock(String lockKey, TimeUnit unit, int waitTime, int leaseTime);

 void unlock(String lockKey);

 void unlock(RLock lock);
}

Lock接口实现类

package com.tuhu.thirdsample.service;

import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;

import java.util.concurrent.TimeUnit;

/**
 * @author chendesheng
 * @create 2019/10/12 10:49
 */
public class RedissonDistributedLocker implements DistributedLocker{

 private RedissonClient redissonClient;

 @Override
 public RLock lock(String lockKey) {
  RLock lock = redissonClient.getLock(lockKey);
  lock.lock();
  return lock;
 }

 @Override
 public RLock lock(String lockKey, int leaseTime) {
  RLock lock = redissonClient.getLock(lockKey);
  lock.lock(leaseTime, TimeUnit.SECONDS);
  return lock;
 }

 @Override
 public RLock lock(String lockKey, TimeUnit unit ,int timeout) {
  RLock lock = redissonClient.getLock(lockKey);
  lock.lock(timeout, unit);
  return lock;
 }

 @Override
 public boolean tryLock(String lockKey, TimeUnit unit, int waitTime, int leaseTime) {
  RLock lock = redissonClient.getLock(lockKey);
  try {
   return lock.tryLock(waitTime, leaseTime, unit);
  } catch (InterruptedException e) {
   return false;
  }
 }

 @Override
 public void unlock(String lockKey) {
  RLock lock = redissonClient.getLock(lockKey);
  lock.unlock();
 }

 @Override
 public void unlock(RLock lock) {
  lock.unlock();
 }

 public void setRedissonClient(RedissonClient redissonClient) {
  this.redissonClient = redissonClient;
 }
}

redisson属性装配类

package com.tuhu.thirdsample.common;

import lombok.Data;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

/**
 * @author chendesheng
 * @create 2019/10/11 20:04
 */
@Configuration
@ConfigurationProperties(prefix = "redisson")
@ConditionalOnProperty("redisson.password")
@Data
public class RedissonProperties {

 private int timeout = 3000;

 private String address;

 private String password;

 private int database = 0;

 private int connectionPoolSize = 64;

 private int connectionMinimumIdleSize=10;

 private int slaveConnectionPoolSize = 250;

 private int masterConnectionPoolSize = 250;

 private String[] sentinelAddresses;

 private String masterName;

}

SpringBoot自动装配类

package com.tuhu.thirdsample.configuration;

import com.tuhu.thirdsample.common.RedissonProperties;
import com.tuhu.thirdsample.service.DistributedLocker;
import com.tuhu.thirdsample.service.RedissonDistributedLocker;

import com.tuhu.thirdsample.util.RedissonLockUtil;
import org.apache.commons.lang3.StringUtils;
import org.redisson.Redisson;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;
import org.redisson.config.SentinelServersConfig;
import org.redisson.config.SingleServerConfig;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @author chendesheng
 * @create 2019/10/12 10:50
 */
@Configuration
@ConditionalOnClass(Config.class)
@EnableConfigurationProperties(RedissonProperties.class)
public class RedissonAutoConfiguration {

 @Autowired
 private RedissonProperties redissonProperties;

 /**
  * 哨兵模式自动装配
  * @return
  */
 @Bean
 @ConditionalOnProperty(name="redisson.master-name")
 RedissonClient redissonSentinel() {
  Config config = new Config();
  SentinelServersConfig serverConfig = config.useSentinelServers().addSentinelAddress(redissonProperties.getSentinelAddresses())
    .setMasterName(redissonProperties.getMasterName())
    .setTimeout(redissonProperties.getTimeout())
    .setMasterConnectionPoolSize(redissonProperties.getMasterConnectionPoolSize())
    .setSlaveConnectionPoolSize(redissonProperties.getSlaveConnectionPoolSize());

  if(StringUtils.isNotBlank(redissonProperties.getPassword())) {
   serverConfig.setPassword(redissonProperties.getPassword());
  }
  return Redisson.create(config);
 }

 /**
  * 单机模式自动装配
  * @return
  */
 @Bean
 @ConditionalOnProperty(name="redisson.address")
 RedissonClient redissonSingle() {
  Config config = new Config();
  SingleServerConfig serverConfig = config.useSingleServer()
    .setAddress(redissonProperties.getAddress())
    .setTimeout(redissonProperties.getTimeout())
    .setConnectionPoolSize(redissonProperties.getConnectionPoolSize())
    .setConnectionMinimumIdleSize(redissonProperties.getConnectionMinimumIdleSize());

  if(StringUtils.isNotBlank(redissonProperties.getPassword())) {
   serverConfig.setPassword(redissonProperties.getPassword());
  }

  return Redisson.create(config);
 }

 /**
  * 装配locker类，并将实例注入到RedissLockUtil中
  * @return
  */
 @Bean
 DistributedLocker distributedLocker(RedissonClient redissonClient) {
  DistributedLocker locker = new RedissonDistributedLocker();
  ((RedissonDistributedLocker) locker).setRedissonClient(redissonClient);
  RedissonLockUtil.setLocker(locker);
  return locker;
 }
}

Lock帮助类

package com.tuhu.thirdsample.util;

import com.tuhu.thirdsample.service.DistributedLocker;
import org.redisson.api.RLock;

import java.util.concurrent.TimeUnit;

/**
 * @author chendesheng
 * @create 2019/10/12 10:54
 */
public class RedissonLockUtil {

 private static DistributedLocker redissLock;

 public static void setLocker(DistributedLocker locker) {
  redissLock = locker;
 }

 /**
  * 加锁
  * @param lockKey
  * @return
  */
 public static RLock lock(String lockKey) {
  return redissLock.lock(lockKey);
 }

 /**
  * 释放锁
  * @param lockKey
  */
 public static void unlock(String lockKey) {
  redissLock.unlock(lockKey);
 }

 /**
  * 释放锁
  * @param lock
  */
 public static void unlock(RLock lock) {
  redissLock.unlock(lock);
 }

 /**
  * 带超时的锁
  * @param lockKey
  * @param timeout 超时时间 单位：秒
  */
 public static RLock lock(String lockKey, int timeout) {
  return redissLock.lock(lockKey, timeout);
 }

 /**
  * 带超时的锁
  * @param lockKey
  * @param unit 时间单位
  * @param timeout 超时时间
  */
 public static RLock lock(String lockKey, TimeUnit unit , int timeout) {
  return redissLock.lock(lockKey, unit, timeout);
 }

 /**
  * 尝试获取锁
  * @param lockKey
  * @param waitTime 最多等待时间
  * @param leaseTime 上锁后自动释放锁时间
  * @return
  */
 public static boolean tryLock(String lockKey, int waitTime, int leaseTime) {
  return redissLock.tryLock(lockKey, TimeUnit.SECONDS, waitTime, leaseTime);
 }

 /**
  * 尝试获取锁
  * @param lockKey
  * @param unit 时间单位
  * @param waitTime 最多等待时间
  * @param leaseTime 上锁后自动释放锁时间
  * @return
  */
 public static boolean tryLock(String lockKey, TimeUnit unit, int waitTime, int leaseTime) {
  return redissLock.tryLock(lockKey, unit, waitTime, leaseTime);
 }
}

控制层

package com.tuhu.thirdsample.task;

import com.tuhu.thirdsample.common.KeyConst;
import lombok.extern.slf4j.Slf4j;

import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.concurrent.TimeUnit;
/**
 * @author chendesheng
 * @create 2019/10/12 11:03
 */
@RestController
@RequestMapping("/lock")
@Slf4j
public class LockController {
 @Autowired
 RedissonClient redissonClient;

 @GetMapping("/task")
 public void task(){
  log.info("task start");
  RLock lock = redissonClient.getLock(KeyConst.REDIS_LOCK_KEY);
  boolean getLock = false;

  try {
   if (getLock = lock.tryLock(0,5,TimeUnit.SECONDS)){
    //执行业务逻辑
    System.out.println("拿到锁干活");

   }else {
    log.info("Redisson分布式锁没有获得锁:{},ThreadName:{}",KeyConst.REDIS_LOCK_KEY,Thread.currentThread().getName());
   }

  } catch (InterruptedException e) {
   log.error("Redisson 获取分布式锁异常,异常信息:{}",e);
  }finally {

   if (!getLock){
    return;
   }
   //如果演示的话需要注释该代码;实际应该放开
   //lock.unlock();
   //log.info("Redisson分布式锁释放锁:{},ThreadName :{}", KeyConst.REDIS_LOCK_KEY, Thread.currentThread().getName());
  }
 }

}

RLock 继承自 java.util.concurrent.locks.Lock ，可以将其理解为一个重入锁，需要手动加锁和释放锁 。

来看它其中的一个方法：tryLock(long waitTime, long leaseTime, TimeUnit unit)

getLock = lock.tryLock(0,5,TimeUnit.SECONDS)

通过 tryLock() 的参数可以看出，在获取该锁时如果被其他线程先拿到锁就会进入等待，等待 waitTime 时间，如果还没用机会获取到锁就放弃，返回 false；若获得了锁，除非是调用 unlock 释放，那么会一直持有锁，直到超过 leaseTime 指定的时间。

以上就是 Redisson 实现分布式锁的核心方法，有人可能要问，那怎么确定拿的是同一把锁，分布式锁在哪？

这就是 Redisson 的强大之处，其底层还是使用的 Redis 来作分布式锁，在我们的RedissonManager中已经指定了 Redis 实例，Redisson 会进行托管，其原理与我们手动实现 Redis 分布式锁类似。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。