摘要
Spring Data Redis 是Spring 框架提供的用于操作Redis的方式,最近整理了下它的用法,解决了使用过程中遇到的一些难点与坑点,希望对大家有所帮助。本文涵盖了Redis的安装、Spring Cache结合Redis的使用、Redis连接池的使用和RedisTemplate的使用等内容。
Redis安装
这里提供Linux和Windows两种安装方式,由于Windows下的版本最高只有3.2版本,所以推荐使用Linux下的版本,目前最新稳定版本为5.0,也是本文中使用的版本。
Linux
这里我们使用Docker环境下的安装方式。
docker pull redis:5.0
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docker run -p 6379:6379 --name redis \
-v /mydata/redis/data:/data \
-d redis:5.0 redis-server --appendonly yes
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Windows
想使用Windows版本的朋友可以使用以下安装方式。
在当前地址栏输入cmd后,执行redis的启动命令:redis-server.exe redis.windows.conf
Spring Cache 操作Redis
Spring Cache 简介
当Spring Boot 结合Redis来作为缓存使用时,最简单的方式就是使用Spring Cache了,使用它我们无需知道Spring中对Redis的各种操作,仅仅通过它提供的@Cacheable 、@CachePut 、@CacheEvict 、@EnableCaching等注解就可以实现缓存功能。
常用注解
@EnableCaching
开启缓存功能,一般放在启动类上。
@Cacheable
使用该注解的方法当缓存存在时,会从缓存中获取数据而不执行方法,当缓存不存在时,会执行方法并把返回结果存入缓存中。一般使用在查询方法上
,可以设置如下属性:
value:缓存名称(必填),指定缓存的命名空间;
key:用于设置在命名空间中的缓存key值,可以使用SpEL表达式定义;
unless:条件符合则不缓存;
condition:条件符合则缓存。
@CachePut
使用该注解的方法每次执行时都会把返回结果存入缓存中。一般使用在新增方法上
,可以设置如下属性:
value:缓存名称(必填),指定缓存的命名空间;
key:用于设置在命名空间中的缓存key值,可以使用SpEL表达式定义;
unless:条件符合则不缓存;
condition:条件符合则缓存。
@CacheEvict
使用该注解的方法执行时会清空指定的缓存。一般使用在更新或删除方法上
,可以设置如下属性:
value:缓存名称(必填),指定缓存的命名空间;
key:用于设置在命名空间中的缓存key值,可以使用SpEL表达式定义;
condition:条件符合则缓存。
使用步骤
<dependency >
<groupId > org.springframework.boot</groupId >
<artifactId > spring-boot-starter-data-redis</artifactId >
</dependency >
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修改配置文件application.yml,添加Redis的连接配置;
spring:
redis:
host: 192.168 .6 .139
database: 0
port: 6379
password:
timeout: 1000 ms
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在启动类上添加@EnableCaching注解启动缓存功能;
@EnableCaching
@SpringBootApplication
public class MallTinyApplication {
public static void main (String[] args) {
SpringApplication.run(MallTinyApplication.class, args);
}
}
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接下来在PmsBrandServiceImpl类中使用相关注解来实现缓存功能,可以发现我们获取品牌详情的方法中使用了@Cacheable注解,在修改和删除品牌的方法上使用了@CacheEvict注解;
@Service
public class PmsBrandServiceImpl implements PmsBrandService {
@Autowired
private PmsBrandMapper brandMapper;
@CacheEvict (value = RedisConfig.REDIS_KEY_DATABASE, key = "'pms:brand:'+#id" )
@Override
public int update (Long id, PmsBrand brand) {
brand.setId(id);
return brandMapper.updateByPrimaryKeySelective(brand);
}
@CacheEvict (value = RedisConfig.REDIS_KEY_DATABASE, key = "'pms:brand:'+#id" )
@Override
public int delete (Long id) {
return brandMapper.deleteByPrimaryKey(id);
}
@Cacheable (value = RedisConfig.REDIS_KEY_DATABASE, key = "'pms:brand:'+#id" , unless = "#result==null" )
@Override
public PmsBrand getItem (Long id) {
return brandMapper.selectByPrimaryKey(id);
}
}
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我们可以调用获取品牌详情的接口测试下效果,此时发现Redis中存储的数据有点像乱码,并且没有设置过期时间;
存储JSON格式数据
此时我们就会想到有没有什么办法让Redis中存储的数据变成标准的JSON格式,然后可以设置一定的过期时间,不设置过期时间容易产生很多不必要的缓存数据。
我们可以通过给RedisTemplate设置JSON格式的序列化器,并通过配置RedisCacheConfiguration设置超时时间来实现以上需求,此时别忘了去除启动类上的@EnableCaching注解,具体配置类RedisConfig代码如下;
@EnableCaching
@Configuration
public class RedisConfig extends CachingConfigurerSupport {
public static final String REDIS_KEY_DATABASE="mall" ;
@Bean
public RedisTemplate<String, Object> redisTemplate (RedisConnectionFactory redisConnectionFactory) {
RedisSerializer<Object> serializer = redisSerializer();
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(redisConnectionFactory);
redisTemplate.setKeySerializer(new StringRedisSerializer());
redisTemplate.setValueSerializer(serializer);
redisTemplate.setHashKeySerializer(new StringRedisSerializer());
redisTemplate.setHashValueSerializer(serializer);
redisTemplate.afterPropertiesSet();
return redisTemplate;
}
@Bean
public RedisSerializer<Object> redisSerializer () {
Jackson2JsonRedisSerializer<Object> serializer = new Jackson2JsonRedisSerializer<>(Object.class);
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
serializer.setObjectMapper(objectMapper);
return serializer;
}
@Bean
public RedisCacheManager redisCacheManager (RedisConnectionFactory redisConnectionFactory) {
RedisCacheWriter redisCacheWriter = RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory);
RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer())).entryTtl(Duration.ofDays(1 ));
return new RedisCacheManager(redisCacheWriter, redisCacheConfiguration);
}
}
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此时我们再次调用获取商品详情的接口进行测试,会发现Redis中已经缓存了标准的JSON格式数据,并且超时时间被设置为了1天。
使用Redis连接池
SpringBoot 1.5.x版本Redis客户端默认是Jedis实现的,SpringBoot 2.x版本中默认客户端是用Lettuce实现的,我们先来了解下Jedis和Lettuce客户端。
Jedis vs Lettuce
Jedis在实现上是直连Redis服务,多线程环境下非线程安全,除非使用连接池,为每个 RedisConnection 实例增加物理连接。
Lettuce是一种可伸缩,线程安全,完全非阻塞的Redis客户端,多个线程可以共享一个RedisConnection,它利用Netty NIO框架来高效地管理多个连接,从而提供了异步和同步数据访问方式,用于构建非阻塞的反应性应用程序。
使用步骤
修改application.yml添加Lettuce连接池配置,用于配置线程数量和阻塞等待时间;
spring:
redis:
lettuce:
pool:
max-active: 8
max-idle: 8
min-idle: 0
max-wait: -1 ms
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由于SpringBoot 2.x中默认并没有使用Redis连接池,所以需要在pom.xml中添加commons-pool2的依赖;
<dependency >
<groupId > org.apache.commons</groupId >
<artifactId > commons-pool2</artifactId >
</dependency >
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如果你没添加以上依赖的话,启动应用的时候就会产生如下错误;
Caused by: java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration$LettucePoolingClientConfigurationBuilder .<init>(LettucePoolingClientConfiguration.java:84) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration.builder(LettucePoolingClientConfiguration.java:48) ~[spring-data-redis-2.1.5.RELEASE.jar:2.1.5.RELEASE]
at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$PoolBuilderFactory .createBuilder(LettuceConnectionConfiguration.java:149) ~[spring-boot-autoconfigure-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.createBuilder(LettuceConnectionConfiguration.java:107) ~[spring-boot-autoconfigure-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.getLettuceClientConfiguration(LettuceConnectionConfiguration.java:93) ~[spring-boot-autoconfigure-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.redisConnectionFactory(LettuceConnectionConfiguration.java:74) ~[spring-boot-autoconfigure-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$$EnhancerBySpringCGLIB $$5caa7e47 .CGLIB$redisConnectionFactory $0 (<generated>) ~[spring-boot-autoconfigure-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$$EnhancerBySpringCGLIB $$5caa7e47 $$FastClassBySpringCGLIB $$b8ae2813 .invoke(<generated>) ~[spring-boot-autoconfigure-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244) ~[spring-core-5.1.5.RELEASE.jar:5.1.5.RELEASE]
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor .intercept(ConfigurationClassEnhancer.java:363) ~[spring-context-5.1.5.RELEASE.jar:5.1.5.RELEASE]
at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$$EnhancerBySpringCGLIB $$5caa7e47 .redisConnectionFactory(<generated>) ~[spring-boot-autoconfigure-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.1.5.RELEASE.jar:5.1.5.RELEASE]
... 111 common frames omitted
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自由操作Redis
Spring Cache 给我们提供了操作Redis缓存的便捷方法,但是也有很多局限性。比如说我们想单独设置一个缓存值的有效期怎么办?我们并不想缓存方法的返回值,我们想缓存方法中产生的中间值怎么办?此时我们就需要用到RedisTemplate这个类了,接下来我们来讲下如何通过RedisTemplate来自由操作Redis中的缓存。
RedisService
定义Redis操作业务类,在Redis中有几种数据结构,比如普通结构(对象),Hash结构、Set结构、List结构,该接口中定义了大多数常用操作方法。
public interface RedisService {
void set (String key, Object value, long time) ;
void set (String key, Object value) ;
Object get (String key) ;
Boolean del (String key) ;
Long del (List<String> keys) ;
Boolean expire (String key, long time) ;
Long getExpire (String key) ;
Boolean hasKey (String key) ;
Long incr (String key, long delta) ;
Long decr (String key, long delta) ;
Object hGet (String key, String hashKey) ;
Boolean hSet (String key, String hashKey, Object value, long time) ;
void hSet (String key, String hashKey, Object value) ;
Map<Object, Object> hGetAll (String key) ;
Boolean hSetAll (String key, Map<String, Object> map, long time) ;
void hSetAll (String key, Map<String, Object> map) ;
void hDel (String key, Object... hashKey) ;
Boolean hHasKey (String key, String hashKey) ;
Long hIncr (String key, String hashKey, Long delta) ;
Long hDecr (String key, String hashKey, Long delta) ;
Set<Object> sMembers (String key) ;
Long sAdd (String key, Object... values) ;
Long sAdd (String key, long time, Object... values) ;
Boolean sIsMember (String key, Object value) ;
Long sSize (String key) ;
Long sRemove (String key, Object... values) ;
List<Object> lRange (String key, long start, long end) ;
Long lSize (String key) ;
Object lIndex (String key, long index) ;
Long lPush (String key, Object value) ;
Long lPush (String key, Object value, long time) ;
Long lPushAll (String key, Object... values) ;
Long lPushAll (String key, Long time, Object... values) ;
Long lRemove (String key, long count, Object value) ;
}
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RedisServiceImpl
RedisService的实现类,使用RedisTemplate来自由操作Redis中的缓存数据。
@Service
public class RedisServiceImpl implements RedisService {
@Autowired
private RedisTemplate<String, Object> redisTemplate;
@Override
public void set (String key, Object value, long time) {
redisTemplate.opsForValue().set(key, value, time, TimeUnit.SECONDS);
}
@Override
public void set (String key, Object value) {
redisTemplate.opsForValue().set(key, value);
}
@Override
public Object get (String key) {
return redisTemplate.opsForValue().get(key);
}
@Override
public Boolean del (String key) {
return redisTemplate.delete(key);
}
@Override
public Long del (List<String> keys) {
return redisTemplate.delete(keys);
}
@Override
public Boolean expire (String key, long time) {
return redisTemplate.expire(key, time, TimeUnit.SECONDS);
}
@Override
public Long getExpire (String key) {
return redisTemplate.getExpire(key, TimeUnit.SECONDS);
}
@Override
public Boolean hasKey (String key) {
return redisTemplate.hasKey(key);
}
@Override
public Long incr (String key, long delta) {
return redisTemplate.opsForValue().increment(key, delta);
}
@Override
public Long decr (String key, long delta) {
return redisTemplate.opsForValue().increment(key, -delta);
}
@Override
public Object hGet (String key, String hashKey) {
return redisTemplate.opsForHash().get(key, hashKey);
}
@Override
public Boolean hSet (String key, String hashKey, Object value, long time) {
redisTemplate.opsForHash().put(key, hashKey, value);
return expire(key, time);
}
@Override
public void hSet (String key, String hashKey, Object value) {
redisTemplate.opsForHash().put(key, hashKey, value);
}
@Override
public Map<Object, Object> hGetAll (String key) {
return redisTemplate.opsForHash().entries(key);
}
@Override
public Boolean hSetAll (String key, Map<String, Object> map, long time) {
redisTemplate.opsForHash().putAll(key, map);
return expire(key, time);
}
@Override
public void hSetAll (String key, Map<String, Object> map) {
redisTemplate.opsForHash().putAll(key, map);
}
@Override
public void hDel (String key, Object... hashKey) {
redisTemplate.opsForHash().delete(key, hashKey);
}
@Override
public Boolean hHasKey (String key, String hashKey) {
return redisTemplate.opsForHash().hasKey(key, hashKey);
}
@Override
public Long hIncr (String key, String hashKey, Long delta) {
return redisTemplate.opsForHash().increment(key, hashKey, delta);
}
@Override
public Long hDecr (String key, String hashKey, Long delta) {
return redisTemplate.opsForHash().increment(key, hashKey, -delta);
}
@Override
public Set<Object> sMembers (String key) {
return redisTemplate.opsForSet().members(key);
}
@Override
public Long sAdd (String key, Object... values) {
return redisTemplate.opsForSet().add(key, values);
}
@Override
public Long sAdd (String key, long time, Object... values) {
Long count = redisTemplate.opsForSet().add(key, values);
expire(key, time);
return count;
}
@Override
public Boolean sIsMember (String key, Object value) {
return redisTemplate.opsForSet().isMember(key, value);
}
@Override
public Long sSize (String key) {
return redisTemplate.opsForSet().size(key);
}
@Override
public Long sRemove (String key, Object... values) {
return redisTemplate.opsForSet().remove(key, values);
}
@Override
public List<Object> lRange (String key, long start, long end) {
return redisTemplate.opsForList().range(key, start, end);
}
@Override
public Long lSize (String key) {
return redisTemplate.opsForList().size(key);
}
@Override
public Object lIndex (String key, long index) {
return redisTemplate.opsForList().index(key, index);
}
@Override
public Long lPush (String key, Object value) {
return redisTemplate.opsForList().rightPush(key, value);
}
@Override
public Long lPush (String key, Object value, long time) {
Long index = redisTemplate.opsForList().rightPush(key, value);
expire(key, time);
return index;
}
@Override
public Long lPushAll (String key, Object... values) {
return redisTemplate.opsForList().rightPushAll(key, values);
}
@Override
public Long lPushAll (String key, Long time, Object... values) {
Long count = redisTemplate.opsForList().rightPushAll(key, values);
expire(key, time);
return count;
}
@Override
public Long lRemove (String key, long count, Object value) {
return redisTemplate.opsForList().remove(key, count, value);
}
}
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RedisController
测试RedisService中缓存操作的Controller,大家可以调用测试下。
@Api (tags = "RedisController" , description = "Redis测试" )
@Controller
@RequestMapping ("/redis" )
public class RedisController {
@Autowired
private RedisService redisService;
@Autowired
private PmsBrandService brandService;
@ApiOperation ("测试简单缓存" )
@RequestMapping (value = "/simpleTest" , method = RequestMethod.GET)
@ResponseBody
public CommonResult<PmsBrand> simpleTest () {
List<PmsBrand> brandList = brandService.list(1 , 5 );
PmsBrand brand = brandList.get(0 );
String key = "redis:simple:" + brand.getId();
redisService.set(key, brand);
PmsBrand cacheBrand = (PmsBrand) redisService.get(key);
return CommonResult.success(cacheBrand);
}
@ApiOperation ("测试Hash结构的缓存" )
@RequestMapping (value = "/hashTest" , method = RequestMethod.GET)
@ResponseBody
public CommonResult<PmsBrand> hashTest () {
List<PmsBrand> brandList = brandService.list(1 , 5 );
PmsBrand brand = brandList.get(0 );
String key = "redis:hash:" + brand.getId();
Map<String, Object> value = BeanUtil.beanToMap(brand);
redisService.hSetAll(key, value);
Map<Object, Object> cacheValue = redisService.hGetAll(key);
PmsBrand cacheBrand = BeanUtil.mapToBean(cacheValue, PmsBrand.class, true );
return CommonResult.success(cacheBrand);
}
@ApiOperation ("测试Set结构的缓存" )
@RequestMapping (value = "/setTest" , method = RequestMethod.GET)
@ResponseBody
public CommonResult<Set<Object>> setTest() {
List<PmsBrand> brandList = brandService.list(1 , 5 );
String key = "redis:set:all" ;
redisService.sAdd(key, (Object[]) ArrayUtil.toArray(brandList, PmsBrand.class));
redisService.sRemove(key, brandList.get(0 ));
Set<Object> cachedBrandList = redisService.sMembers(key);
return CommonResult.success(cachedBrandList);
}
@ApiOperation ("测试List结构的缓存" )
@RequestMapping (value = "/listTest" , method = RequestMethod.GET)
@ResponseBody
public CommonResult<List<Object>> listTest() {
List<PmsBrand> brandList = brandService.list(1 , 5 );
String key = "redis:list:all" ;
redisService.lPushAll(key, (Object[]) ArrayUtil.toArray(brandList, PmsBrand.class));
redisService.lRemove(key, 1 , brandList.get(0 ));
List<Object> cachedBrandList = redisService.lRange(key, 0 , 3 );
return CommonResult.success(cachedBrandList);
}
}