73、缓存---分布式锁---Redisson读写锁测试

保证一定读到最新数据，修改期间，写锁是一个排他锁/互斥锁。读锁是一个共享锁。（相当于操作系统中的读写者问题）
写锁没释放读必须等待

测试如下：

@Autowired
    RedissonClient redissonClient;

    @Autowired
    StringRedisTemplate redisTemplate;

    @GetMapping("/write")
    @ResponseBody
    public String writeValue(){
        RReadWriteLock readWriteLock = redissonClient.getReadWriteLock("rw-lock");
        RLock rLock = readWriteLock.writeLock();//获取写锁
        String s = null;
        try {
            //1、该数据加写锁，读数据加读锁
            rLock.lock();
            s = UUID.randomUUID().toString();
            Thread.sleep(30000);
            redisTemplate.opsForValue().set("writeValue", s);
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            rLock.unlock();//解锁
        }

        return s;
    }

    @GetMapping("/read")
    @ResponseBody
    public String readValue(){
        RReadWriteLock readWriteLock = redissonClient.getReadWriteLock("rw-lock");
        RLock rLock = readWriteLock.readLock();//获取读锁
        String s = null;
        try {
            rLock.lock();
            s = redisTemplate.opsForValue().get("writeValue");
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            rLock.unlock();
        }

        return s;
    }