Redis
redis:把一些常用的、访问量高的、不怎么改的数据放入缓存,减少数据库压力和提高访问速度
在Spring Boot项目中中,默认集成Spring Data Redis,Spring Data Redis针对Redis提供了非常方便的操作模版RedisTemplate,并且可以进行连接池自动管理。
maven依赖
<!-- spring boot redis缓存引入 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<!-- 缓存连接池-->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-pool2</artifactId>
</dependency>
<!-- redis 存储 json序列化 -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-jsr310</artifactId>
</dependency>
Redis连接配置
#spring:
redis:
host: ip
port: 6379
database: 0
password: 123456 #默认为空
timeout: 3000ms #最大等待时间,超时则抛出异常,否则请求一直等待
lettuce:
pool:
max-active: 20 #最大连接数,负值表示没有限制,默认8
max-wait: -1 #最大阻塞等待时间,负值表示没限制,默认-1
max-idle: 8 #最大空闲连接,默认8
min-idle: 0 #最小空闲连接,默认0
启动Redis服务
#启动服务
cd /usr/local/redis-5.0.7
bin/redis-server redis.conf
测试类
@SpringBootTest
@RunWith(SpringRunner.class)
public class RedisTemplateTests {
@Resource
private RedisTemplate redisTemplate;
@Resource
private DictMapper dictMapper;
@Test
public void saveDict(){
Dict dict = dictMapper.selectById(1);
//向数据库中存储string类型的键值对, 过期时间5分钟
redisTemplate.opsForValue().set("dict", dict, 5, TimeUnit.MINUTES);
}
}
RedisTemplate默认使用了JDK的序列化方式存储了key和value
Redis配置类
@Configuration
public class RedisConfig {
@Bean
public RedisTemplate<String, Object> redisTemplate(LettuceConnectionFactory redisConnectionFactory) {
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(redisConnectionFactory);
//首先解决key的序列化方式
StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
redisTemplate.setKeySerializer(stringRedisSerializer);
//解决value的序列化方式
Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);
//序列化时将类的数据类型存入json,以便反序列化的时候转换成正确的类型
ObjectMapper objectMapper = new ObjectMapper();
//objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
objectMapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance, ObjectMapper.DefaultTyping.NON_FINAL);
// 解决jackson2无法反序列化LocalDateTime的问题
objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
objectMapper.registerModule(new JavaTimeModule());
jackson2JsonRedisSerializer.setObjectMapper(objectMapper);
redisTemplate.setValueSerializer(jackson2JsonRedisSerializer);
return redisTemplate;
}
}
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