SpringBoot缓存技术

一、SpringBoot整合Ehhcache

添加maven依赖

 <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-cache</artifactId>
 </dependency>
 <dependency>
     <groupId>net.sf.ehcache</groupId>
     <artifactId>ehcache</artifactId>
 </dependency>

创建Ehcache配置文件src/main/resources/ehcache.xml

 <ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">
     <diskStore path="java.io.tmpdir"/>
     <!--defaultCache:echcache 的默认缓存策略-->
     <defaultCache
         maxElementsInMemory="10000"
         eternal="false"
         timeToIdleSeconds="120"
         timeToLiveSeconds="120"
         maxElementsOnDisk="10000000"
         diskExpiryThreadIntervalSeconds="120"
         memoryStoreEvictionPolicy="LRU">
         <persistence strategy="localTempSwap"/>
     </defaultCache>
     <!-- 自定义缓存策略-->
     <cache name="user"
         maxElementsInMemory="10000"
         eternal="false"
         timeToIdleSeconds="120"
         timeToLiveSeconds="120"
         maxElementsOnDisk="10000000"
         diskExpiryThreadIntervalSeconds="120"
         memoryStoreEvictionPolicy="LRU">
         <persistence strategy="localTempSwap"/>
     </cache>
 </ehcache>

在application.properties中添加

spring.cache.ehcache.config=ehcache.xml

在启动类上加注解

@EnableCaching

在业务层可以使用注解缓存数据

 @Override
 @Cacheable(value="user")
 public User findUserById(Integer id) {
     return this.userMapper.findUserById(id);
 }

@Cacheable的作用就是把方法的返回值添加到ehcache缓存中，value属性为ehcache配置文件中的缓存策略，不设定使用默认。

要求实体类需要实现Serializable接口。

@CacheEvict为清除缓存

 @Override
 @CacheEvict(value="user", allEntries=true)
 public void saveUser(User user) {
     this.userMapper.save(user);
 }

二、SpringBoot整合Redis

SpringDataRedis是属于SpringData下的一个模块，作用是简化redis的操作。添加mvaen依赖：

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

编写SpringDataRedis配置类

 @Configuration
 public class RedisConfig {
     @Bean
     public JedisPoolConfig jedisPoolConfig() {
         JedisPoolConfig config = new JedisPoolConfig();
         config.setMaxIdle(10);
         config.setMinIdle(5);
         config.setMaxTotal(20);
         return config;
     }
     @Bean
     public JedisConnectionFactory jedisConnectionFactory(JedisPoolConfig config) {
         JedisConnectionFactory factory = new JedisConnectionFactory();
         factory.setPoolConfig(config);
         factory.setHostName("127.0.0.1");
         factory.setPort(6379);
         return factory;
     }
     @Bean
     public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
         RedisTemplate<String, Object> template = new RedisTemplate<>();
         template.setConnectionFactory(factory);
         template.setKeySerializer(new StringRedisSerializer());
         template.setValueSerializer(new StringRedisSerializer());
         return template;
     }
 }

也可以把参数独立出来

 spring.redis.pool.max-idle=10
 spring.redis.pool.min-idle=5
 spring.redis.pool.max-total=20
 spring.redis.hostname=127.0.0.1
 spring.redis.port=6379

 @Configuration
 public class RedisConfig {
     @Bean
     @ConfigurationPropeties(prefix="spring.redis.pool")
     public JedisPoolConfig jedisPoolConfig() {
         JedisPoolConfig config = new JedisPoolConfig();
         //其他参数已经自动注入
         return config;
     }
     @Bean
     @ConfigurationProperties(prefix="spring.redis")
     public JedisConnectionFactory jedisConnectionFactory(JedisPoolConfig config) {
         JedisConnectionFactory factory = new JedisConnectionFactory();
         factory.setPoolConfig(config);
         //其他参数已经自动注入
         return factory;
     }
     @Bean
     public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
         RedisTemplate<String, Object> template = new RedisTemplate<>();
         template.setConnectionFactory(factory);
         template.setKeySerializer(new StringRedisSerializer());
         template.setValueSerializer(new StringRedisSerializer());
         return template;
     }
 }

使用springboot中的redis非常简单

 this.redisTemplate.opsForValue().set("user", user);
 (User)this.redisTemplate.opsForValue().get("user");