SpringBoot项目接入Redisson分布式锁

概述

可参考以下网站 Redisson Github WIKI

Redisson是一个在Redis的基础上实现的Java驻内存数据网格（In-Memory Data Grid）。提供了使用Redis的最简单和最便捷的方法。促进使用者对Redis的关注分离。并且底层采用的是Netty框架。

我的理解：基于Netty封装了一些利用了Redis特性的工具，让我们可以更高效、更简便的使用Redis。

本文主要介绍，如果在一个springboot项目中接入并使用Redisson网络提供的可重入锁（Reentrant Lock），特别注意：这只是Redisson整个框架中的一小部分。

如何使用

说明：该项目是Springboot（1.5.10.RELEASE），其中已经集成了Redis（如何集成这个就不多介绍这个了= =），以下仅演示接入并使用Redisson的一种方式，更多接入方式

引入maven依赖

        <dependency>
            <groupId>org.redisson</groupId>
            <artifactId>redisson</artifactId>
            <version>3.5.0</version>
        </dependency>

配置文件

redisson:
  address: redis://${spring.redis.host}:${spring.redis.port}        # redis地址
  timeout: 3000                                                     # 超时时间
  connectionPoolSize: 64                                            # 连接池大小 默认64
  connectionMinimumIdleSize: 32                                     # 最小空闲连接数 默认32

使用单机模式Redis

配置类（Redis集成配置已省略）

package com.distributedlock.config;

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 RedissonConfig {

    /**
     * redis连接地址
     */
    @Value("${redisson.address}")
    private String redissonAddress;

    /**
     * redis连接密码
     */
    @Value("${spring.redis.password}")
    private String password;

    /**
     * redis连接时间
     */
    @Value("${redisson.timeout}")
    private Integer timeout;

    /**
     * redis连接池大小
     */
    @Value("${redisson.connectionPoolSize}")
    private Integer connectionPoolSize;

    /**
     * redis最小连接空闲数
     */
    @Value("${redisson.connectionMinimumIdleSize}")
    private Integer connectionMinimumIdleSize;

    /**
     * 获取单机模式配置
     * @return
     */
    @Bean
    public RedissonClient getRedissonClient() {
        Config config = new Config();
        config.useSingleServer()
                .setAddress(redissonAddress)
                .setPassword(password)
                .setTimeout(timeout)
                .setConnectionPoolSize(connectionPoolSize)
                .setConnectionMinimumIdleSize(connectionMinimumIdleSize);
        return Redisson.create(config);
    }

封装接口和实现类（方便使用）

接口：定义一些要用到的方法，可通过实现类来根据需求重写方法

package com.distributedlock.lock.redisson;

import java.util.concurrent.TimeUnit;

/**
 * redisson分布式锁
 * 注意：
 * 1. 可自定义锁过期时间、获取锁间隔时间、获取锁超时时间、获取锁重试次数
 * 2. 如未设置以上参数，则使用默认值
 */
public interface IRedissionLock {

    boolean tryLock(String key);

    boolean tryLock(String key, long waitTime);

    boolean tryLock(String key, long waitTime, long sleepTime);

    boolean tryLock(String key, long waitTime, long sleepTime, TimeUnit timeUnit);

    void unLock(String key);
}

接口实现类：

package com.distributedlock.lock.redisson;

import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.TimeUnit;

@Component
public class RedssionLockImpl implements IRedissionLock{

    @Autowired
    private RedissonClient redissonClient;

    /**
     * 获取锁超时时间
     */
    private static final long waitTime = 50000L;

    /**
     * 锁过期时间
     * 单个线程拥有锁的最长时间（有自动续期的逻辑）
     */
    private static final long leaseTime = 20000L;

    private static TimeUnit timeUnit = TimeUnit.MILLISECONDS;

    private static final ConcurrentMap<String, RLock> rLockConcurrentMap = new ConcurrentHashMap<>();

    @Value("${redisson.lockKeyPre}")
    private String lockKeyPre;

    @Override
    public boolean tryLock(String key) {
        return this.tryLock(key, waitTime, leaseTime, timeUnit);
    }

    @Override
    public boolean tryLock(String key, long leaseTime) {
        return this.tryLock(key, waitTime, leaseTime, timeUnit);
    }

    @Override
    public boolean tryLock(String key, long leaseTime, long sleepTime) {
        return this.tryLock(key, waitTime, sleepTime, timeUnit);
    }

    @Override
    public boolean tryLock(String key, long waitTime, long leaseTime, TimeUnit timeUnit) {
        RLock rLock = this.getRLock(lockKeyPre + key);
        try {
            return rLock.tryLock(waitTime, leaseTime, timeUnit);
        } catch (Exception e) {
            return false;
        }
    }

    @Override
    public void unLock(String key) {
        this.getRLock(lockKeyPre + key).unlock();
    }

    private RLock getRLock(String objectName) {
        String saveKey = Thread.currentThread().getId() + ":" + objectName;
        RLock rLock = rLockConcurrentMap.get(saveKey);

        if (rLock == null) {
            rLock = this.newRLock(objectName);
            rLockConcurrentMap.put(saveKey, rLock);
        }

        return rLock;
    }

    private RLock newRLock(String key) {
        return redissonClient.getLock(key);
    }

}

使用示例

package com.distributedlock;

import com.distributedlock.lock.redisson.IRedissionLock;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

@RunWith(SpringRunner.class)
@SpringBootTest
public class RedissonLockTest {

    @Autowired
    private IRedissionLock redssionLock;

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    private Integer sum = 0;


    /**
     * redisLock demo
     *
     * @throws InterruptedException
     */
    @Test
    public void test() throws InterruptedException {
        logger.info("redis-lock-test:    client start! ");
        ExecutorService executorService = Executors.newCachedThreadPool();
        //同步工具类
        CountDownLatch latch = new CountDownLatch(100);
        for (int i = 0; i < 100; i++) {
            //从线程池中获取100个线程，并执行
            executorService.submit(new MyLock("client-" + i, latch));
            logger.info("client-" + i + " init completed !");
        }
        //关闭线程池
        executorService.shutdown();
        latch.await();
        logger.info("redis-lock-test: all client completed -> sum: {} ", sum);
    }


    class MyLock implements Runnable {

        private String name;
        private CountDownLatch latch;

        public MyLock(String name, CountDownLatch latch) {
            this.name = name;
            this.latch = latch;
        }

        @Override
        public void run() {
            String key = "root";
            try {
                if (redssionLock.tryLock(key)) {
                    sum += 1;
                    logger.info(this.name + " get lock success key: " + key + "  work -> sum = " + sum);
                } else {
                    logger.error(this.name + " get lock key: " + key + " timeout!");
                }
                latch.countDown();

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    redssionLock.unLock(key);
                    logger.info(this.name + "    release    " + key);
                } catch (Exception e) {
                    logger.error(this.name + " release " + key + " error");
                }
            }
        }
    }
}