3月
05
Redis安装
Redis的安装网上文档很多，官方也有非常详细的安装文档，这里就不再赘述，如果是个人开发，建议使用Docker进行安装，只需以下一行命令即可完成完整docker run -itd --name redis -p 6379:6379 redis
执行以下命令查看是否运行成功
➜ docker exec -it redis redis-cli 127.0.0.1:6379> ping PONG
Spring boot集成Redis
- 引入依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-pool2</artifactId>
</dependency>
- 配置
spring.redis.host=127.0.0.1 spring.redis.port=6379 #客户端超时 spring.redis.timeout=10000 #最大连接数 spring.redis.lettuce.pool.max-active=20 #最小空闲 spring.redis.lettuce.pool.min-idle=5 #连接超时 spring.redis.lettuce.pool.max-wait=5000ms #最大空闲 spring.redis.lettuce.pool.max-idle=20
- 启动类添加注解
@EnableCaching
@SpringBootApplication
@EnableCaching
public class RedisApplication {
public static void main(String[] args) {
SpringApplication.run(RedisApplication.class, args);
}
}
- 编写配置类，可以参考以下代码
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheWriter;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.*;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;
/**
* @Description:
* @author: jianfeng.zheng
* @since: 2021/3/3 10:53 下午
* @history: 1.2021/3/3 created by jianfeng.zheng
*/
@Configuration
public class RedisConfig {
@Bean
RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
redisTemplate.setConnectionFactory(redisConnectionFactory);
redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());
redisTemplate.setKeySerializer(new StringRedisSerializer());
redisTemplate.setHashKeySerializer(new StringRedisSerializer());
redisTemplate.afterPropertiesSet();
return redisTemplate;
}
@Bean
public RedisCacheManager redisCacheManager(RedisConnectionFactory redisConnectionFactory) {
RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()));
redisCacheConfiguration.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()));
Map<String, RedisCacheConfiguration> redisExpireConfig = new HashMap<>();
//这里设置了一个一分钟的超时配置，如果需要增加更多超时配置参考这个新增即可
redisExpireConfig.put("1min", RedisCacheConfiguration.defaultCacheConfig()
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()))
.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()))
.entryTtl(Duration.ofMinutes(1)).disableCachingNullValues());
RedisCacheManager redisCacheManager = RedisCacheManager.builder(RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory))
.cacheDefaults(redisCacheConfiguration)
.withInitialCacheConfigurations(redisExpireConfig)
.transactionAware()
.build();
return redisCacheManager;
}
}
Spring boot 1.x的redis配置和Spring boot 2.x的redis配置有很大差别，主要是2.x使用了lettuce客户端，所以网上看到的一些1.x的参考代码在2.x无法使用
- 一个简单的示例
@RestController
@RequestMapping(value = "/user")
public class UserController {
@GetMapping(value = "/info")
@Cacheable(value = "user", key = "#uid")
public User getUser(@RequestParam(value = "uid") String uid) {
System.out.println("getUser====>" + uid);
User user = new User();
user.setUid(uid);
user.setEmail(uid + "@definesys.com");
user.setName(uid + ":" + System.currentTimeMillis());
return user;
}
}
@Cacheable(value = "user", key = "#uid")注解将开启缓存，接口返回的数据将会被缓存，value是缓存的名称，key是缓存的健，可以使用SpEL表达式。
用curl调用接口
➜ curl http://localhost:8089/user/info\?uid\=jianfeng
{"uid":"jianfeng","name":"jianfeng:1614870102913","email":"jianfeng@definesys.com"}%
用redis-cli登录redis查看
➜ skywalking git:(master) ✗ docker exec -it redis redis-cli
127.0.0.1:6379> keys *
1) "user::jianfeng"
127.0.0.1:6379> get user::jianfeng
{
"@class": "com.poc.redis.User",
"uid": "jianfeng",
"name": "jianfeng:1614870102913",
"email": "jianfeng@definesys.com"
}
127.0.0.1:6379> ttl user::jianfeng
(integer) -1
可以看到，redis创建了一个名称为user::jianfeng的键，值为java对象的JSON字符串，并且增加了一个@class的字段表示序列化的类，该缓存过期时间为-1也就是永不过期。这时候再用curl测试会发现结果还是一样的
➜ curl http://localhost:8089/user/info\?uid\=jianfeng
{"uid":"jianfeng","name":"jianfeng:1614870102913","email":"jianfeng@definesys.com"}%
如果没有缓存，因为我们name字段的代码是 user.setName(uid + ":" + System.currentTimeMillis());所以理论上每次调用都应该不一样，因为有了缓存所以方法逻辑不会被执行，直接从缓存中取出数据。
缓存过期时间
我们在缓存配置类里面设置了一个1min的配置
redisExpireConfig.put("1min", RedisCacheConfiguration.defaultCacheConfig()
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()))
我们修改下代码
@Cacheable(value = "1min", key = "#uid")
public User getUser(@RequestParam(value = "uid") String uid) {...}
调用接口后查看redis缓存数据
➜ docker exec -it redis redis-cli 127.0.0.1:6379> keys * 1) "1min::jianfeng" 127.0.0.1:6379> ttl 1min::jianfeng (integer) 45
这时候你不断的执行ttl 1min::jianfeng命令会发现时间在减少，当减少到0时，redis就会清除掉缓存
Cacheable可以指定多个名称 @Cacheable(value = {"1min", "2min"}, key = "#uid")这样只要其中任何一个缓存有效都能得到数据
缓存相关注解
除了Cacheable还有其他跟缓存相关的注解
- CachePut
CachePut可以将数据放入缓存，一般insert操作和update操作可以使用该注解，如果指定的key数据存在就更新数据
- CacheEvict
CacheEvict可以删除缓存数据，一般delete操作的接口可以使用该注解
- Caching
Caching是三个的集合，定义如下
public @interface Caching {
Cacheable[] cacheable() default {};
CachePut[] put() default {};
CacheEvict[] evict() default {};
}
一个完整的增删改查缓存例子
@RestController
@RequestMapping("user")
public class RedisController {
@Autowired
private UserMapper userMapper;
@PostMapping("/add")
@CachePut(value = "neverExpire", key = "#user.uid")
public User add(@RequestBody User user) {
userMapper.insert(user);
return user;
}
@PostMapping("/update")
@CachePut(value = "neverExpire", key = "#user.uid")
public User update(@RequestBody User user) {
return user;
}
@GetMapping("/delete")
@CacheEvict(value = "neverExpire", key = "#uid")
public String delete(@RequestParam(value = "uid") String uid) {
return uid;
}
@GetMapping("/detail")
@Cacheable(value = "neverExpire", key = "#result")
public User deteail(@RequestParam(value = "uid") String uid) {
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.eq("uid", uid);
return userMapper.selectOne(queryWrapper);
}
}
Address: https://zhengjianfeng.cn/?p=520
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