太疯狂了（java缓存设计模式）java缓存技术，面试官要求我研究一个Java缓存框架，哪个比较好呢？，java缓存框架 学哪个先，

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency>

@Configurationpublic class RedisConfig {@Autowiredprivate RedisTemplate redisTemplate;//序列化设置一下@PostConstructpublic void setRedisTemplate() {redisTemplate.setKeySerializer(new StringRedisSerializer());redisTemplate.setValueSerializer(new JdkSerializationRedisSerializer());}}

@Overridepublic DsAprovinces selectById(Integer id) {String key = String.valueOf(id);DsAprovinces dsAprovinces= null;//1.从redis查dsAprovinces = (DsAprovinces)redisTemplate.opsForValue().get(key);//2.如果不空if(null!= dsAprovinces) {System.out.println("redis中查到了");return dsAprovinces;}//3.查询数据库dsAprovinces = dsAprovincesMapper.selectById(id);//3.放入缓存if(null!= dsAprovinces) {System.out.println("从数据库中查,放入缓存....");redisTemplate.opsForValue().set(key,dsAprovinces);redisTemplate.expire(key,60, TimeUnit.SECONDS); //60秒有效期}return dsAprovinces;}

//更新:确保机制：实行双删public int update(DsAprovinces dsAprovinces) {redisTemplate.delete(String.valueOf(dsAprovinces.getId()));int i = dsAprovincesMapper.updateById(dsAprovinces);redisTemplate.delete(String.valueOf(dsAprovinces.getId()));return i;}

@Configuration@EnableCaching //开启spring缓存public class MyCacheConfig extends CachingConfigurerSupport {//使用redis做为缓存@Beanpublic CacheManager cacheManager(RedisConnectionFactory connectionFactory) {//1.redis缓存管理器RedisCacheManager.RedisCacheManagerBuilder builder = RedisCacheManager.builder(connectionFactory);//2.设置一些参数 //统一设置20s有效期builder.cacheDefaults(RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ofSeconds(2000)));builder.transactionAware();RedisCacheManager build = builder.build();return build;}//可以自定义key的生成策略@Overridepublic KeyGenerator keyGenerator() {return new KeyGenerator() {@Overridepublic Object generate(Object target, Method method, Object... objects) {//1.缓冲StringBuilder sb = new StringBuilder();//2.类名sb.append(target.getClass().getSimpleName());//3.方法名sb.append(method.getName());//4.参数值for (Object obj : objects) {sb.append(obj.toString());}return sb.toString();}};}}

@Service@Primary@CacheConfig(cacheNames = "provinces") //key键会添加provinces::public class AprovincesServiceImpl2 implements IAprovincesService {@Autowiredprivate DsAprovincesMapper dsAprovincesMapper;@Autowiredprivate RedisTemplate redisTemplate;@Override@Cacheable(key = "#id")//@Cacheablepublic DsAprovinces selectById(Integer id) {//3.查询数据库DsAprovinces dsAprovinces = dsAprovincesMapper.selectById(id);return dsAprovinces;}//更新:确保机制：实行双删@CachePut(key = "#dsAprovinces.id")public DsAprovinces update(DsAprovinces dsAprovinces) {dsAprovincesMapper.updateById(dsAprovinces);return dsAprovinces;}//添加@CachePut(key = "#dsAprovinces.id")public DsAprovinces save(DsAprovinces dsAprovinces) {dsAprovincesMapper.insert(dsAprovinces);return dsAprovinces;}//删除@CacheEvictpublic int delete(Integer id) {int i = dsAprovincesMapper.deleteById(id);return i;}}

@Servicepublic class AprovincesServiceImpl3 implements IAprovincesService {@Autowiredprivate DsAprovincesMapper dsAprovincesMapper;@Autowiredprivate RedisTemplate redisTemplate;@Autowiredpublic CacheManager cacheManager;@Overridepublic DsAprovinces selectById(Integer id) {System.out.println("=======================开始");//1.从缓存中取数据Cache provinces1 = cacheManager.getCache("provinces");Cache.ValueWrapper provinces = cacheManager.getCache("provinces").get(id);//2. 如果缓存中有数据，则返回if(null != provinces) {System.out.println("====从缓从中拿数据=======");return (DsAprovinces)provinces.get();}//3.如果缓存中没有，先加把锁doLock(id+"");//DsAprovinces dsAprovinces = null;try {//4.0从第二个线程进来后，查一下provinces = cacheManager.getCache("provinces").get(id);if(null != provinces) {System.out.println("====从缓从中拿数据=======");return (DsAprovinces)provinces.get();}//4.查询数据库dsAprovinces = dsAprovincesMapper.selectById(id);//5.把数据放入缓存if(null != dsAprovinces) {System.out.println("查询数据库，并放入缓存....");cacheManager.getCache("provinces").put(id,dsAprovinces);}} catch (Exception e) {e.printStackTrace();} finally {releaseLock(id+"");}return dsAprovinces;}//=====================================分布式加锁和释放锁封装start=========================//分布式存放锁,这个map是线程安全的private ConcurrentHashMap<String,Lock> locks = new ConcurrentHashMap<>();//依据主键进行加锁private void doLock(String id) {//1.创建一个可重入锁ReentrantLock newlock = new ReentrantLock();//2.如 果存在id,则返回旧值，如果不存在, 放入，返回nullLock old = locks.putIfAbsent(id,newlock);//3.如果已存在idif(null != old) {old.lock();}else {newlock.lock();}}//释放 一下private void releaseLock(String id) {//获取到锁ReentrantLock lock = (ReentrantLock)locks.get(id);//判断if(null != lock && lock.isHeldByCurrentThread() ) {lock.unlock();}}//=====================================分布式加锁和释放锁封装end=========================

CountDownLatch cw = new CountDownLatch(8);@GetMapping("/selectById1/{id}")public DsAprovinces selectById1(@PathVariable Integer id) {for (int i = 0; i < 8; i++) {new Thread(new Runnable() {@Overridepublic void run() {try {cw.await();aprovincesService.selectById(id);} catch (InterruptedException e) {e.printStackTrace();} finally {}}}).start();cw.countDown();}return aprovincesService.selectById(id);}