springboot2整合redis使用lettuce连接池的方法(解决lettuce连接池无效问题)

lettuce客户端

Lettuce 和 Jedis 的都是连接Redis Server的客户端程序。Jedis在实现上是直连redis server，多线程环境下非线程安全（即多个线程对一个连接实例操作，是线程不安全的），除非使用连接池，为每个Jedis实例增加物理连接。Lettuce基于Netty的连接实例（StatefulRedisConnection），可以在多个线程间并发访问，且线程安全，满足多线程环境下的并发访问（即多个线程公用一个连接实例，线程安全），同时它是可伸缩的设计，一个连接实例不够的情况也可以按需增加连接实例。

添加依赖

dependencies {
 implementation 'org.springframework.boot:spring-boot-starter-jdbc'
 implementation 'org.springframework.boot:spring-boot-starter-data-redis'
 implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
 implementation 'org.springframework.boot:spring-boot-starter-web'
 implementation 'org.mybatis.spring.boot:mybatis-spring-boot-starter:2.1.3'
 //lettuce依赖commons-pool2
 compile group: 'org.apache.commons', name: 'commons-pool2', version: '2.6.2'
 runtimeOnly 'mysql:mysql-connector-java'
 compileOnly 'org.projectlombok:lombok'
 annotationProcessor 'org.projectlombok:lombok'
 testImplementation('org.springframework.boot:spring-boot-starter-test') {
  exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
 }
 compile('org.springframework.boot:spring-boot-starter-cache')
}

application.properties 添加redis连接信息

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mytest?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=123456

server.port=8945

#redis数据库默认使用db0
spring.redis.database=2
spring.redis.password=
spring.redis.port=6379
spring.redis.host=127.0.0.1
# 连接超时时间
spring.redis.timeout=5000
# 连接池最大连接数（使用负值表示没有限制）
spring.redis.lettuce.pool.max-active=3
# 连接池中的最小空闲连接
spring.redis.lettuce.pool.min-idle=2
# 连接池中的最大空闲连接
spring.redis.lettuce.pool.max-idle=3
# 连接池最大阻塞等待时间（使用负值表示没有限制）
spring.redis.lettuce.pool.max-wait=-1
#在关闭客户端连接之前等待任务处理完成的最长时间，在这之后，无论任务是否执行完成，都会被执行器关闭，默认100ms
spring.redis.lettuce.shutdown-timeout=100
#是否缓存空值
spring.cache.redis.cache-null-values=false

编写配置类

package org.example.base.config;

import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.jsontype.impl.LaissezFaireSubTypeValidator;
import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.RedisPassword;
import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
import org.springframework.data.redis.connection.lettuce.LettuceClientConfiguration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;

import java.time.Duration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * @author l
 * @date Created in 2020/11/3 10:51
 */
@Configuration
@EnableCaching
public class RedisConfig {
 @Value("${spring.redis.database}")
 private int database;

 @Value("${spring.redis.host}")
 private String host;

 @Value("${spring.redis.password}")
 private String password;

 @Value("${spring.redis.port}")
 private int port;

 @Value("${spring.redis.timeout}")
 private long timeout;

 @Value("${spring.redis.lettuce.shutdown-timeout}")
 private long shutDownTimeout;

 @Value("${spring.redis.lettuce.pool.max-idle}")
 private int maxIdle;

 @Value("${spring.redis.lettuce.pool.min-idle}")
 private int minIdle;

 @Value("${spring.redis.lettuce.pool.max-active}")
 private int maxActive;

 @Value("${spring.redis.lettuce.pool.max-wait}")
 private long maxWait;

 Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);

 @Bean
 public LettuceConnectionFactory lettuceConnectionFactory() {
  GenericObjectPoolConfig genericObjectPoolConfig = new GenericObjectPoolConfig();
  genericObjectPoolConfig.setMaxIdle(maxIdle);
  genericObjectPoolConfig.setMinIdle(minIdle);
  genericObjectPoolConfig.setMaxTotal(maxActive);
  genericObjectPoolConfig.setMaxWaitMillis(maxWait);
  genericObjectPoolConfig.setTimeBetweenEvictionRunsMillis(100);
  RedisStandaloneConfiguration redisStandaloneConfiguration = new RedisStandaloneConfiguration();
  redisStandaloneConfiguration.setDatabase(database);
  redisStandaloneConfiguration.setHostName(host);
  redisStandaloneConfiguration.setPort(port);
  redisStandaloneConfiguration.setPassword(RedisPassword.of(password));
  LettuceClientConfiguration clientConfig = LettucePoolingClientConfiguration.builder()
    .commandTimeout(Duration.ofMillis(timeout))
    .shutdownTimeout(Duration.ofMillis(shutDownTimeout))
    .poolConfig(genericObjectPoolConfig)
    .build();

  LettuceConnectionFactory factory = new LettuceConnectionFactory(redisStandaloneConfiguration, clientConfig);
//  factory.setShareNativeConnection(true);
//  factory.setValidateConnection(false);
  return factory;
 }

 @Bean
 public RedisTemplate<String, Object> redisTemplate(LettuceConnectionFactory lettuceConnectionFactory) {
  RedisTemplate<String, Object> template = new RedisTemplate<>();
  template.setConnectionFactory(lettuceConnectionFactory);
  //使用Jackson2JsonRedisSerializer替换默认的JdkSerializationRedisSerializer来序列化和反序列化redis的value值
  ObjectMapper mapper = new ObjectMapper();
  mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
  mapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance,
    ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
  jackson2JsonRedisSerializer.setObjectMapper(mapper);
  StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
  //key采用String的序列化方式
  template.setKeySerializer(stringRedisSerializer);
  // hash的key也采用String的序列化方式
  template.setHashKeySerializer(stringRedisSerializer);
  // value序列化方式采用jackson
  template.setValueSerializer(jackson2JsonRedisSerializer);
  // hash的value序列化方式采用jackson
  template.setHashValueSerializer(jackson2JsonRedisSerializer);
  template.afterPropertiesSet();
  return template;
 }

 @Bean("redisCacheManager")
 @Primary
 public CacheManager cacheManager( LettuceConnectionFactory lettuceConnectionFactory) {
  RedisSerializer<String> redisSerializer = new StringRedisSerializer();

  //解决查询缓存转换异常的问题
  ObjectMapper mapper = new ObjectMapper();
  mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
  mapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance,
    ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);
  jackson2JsonRedisSerializer.setObjectMapper(mapper);

  // 配置1 ,
  RedisCacheConfiguration config1 = RedisCacheConfiguration.defaultCacheConfig()
    //缓存失效时间
    .entryTtl(Duration.ofSeconds(30))
    //key序列化方式
    .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
    //value序列化方式
    .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
    //不允许缓存null值
    .disableCachingNullValues();
  //配置2 ,
  RedisCacheConfiguration config2 = RedisCacheConfiguration.defaultCacheConfig()
    .entryTtl(Duration.ofMinutes(1000))
    .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
    .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
    .disableCachingNullValues();

  //设置一个初始化的缓存空间set集合
  Set<String> cacheNames = new HashSet<>();
  cacheNames.add("my-redis-cache1");
  cacheNames.add("my-redis-cache2");

  //对每个缓存空间应用不同的配置
  Map<String, RedisCacheConfiguration> configurationMap = new HashMap<>(3);
  configurationMap.put("my-redis-cache1", config1);
  configurationMap.put("my-redis-cache2", config2);

  return RedisCacheManager.builder(lettuceConnectionFactory)
    //默认缓存配置
    .cacheDefaults(config1)
    //初始化缓存空间
    .initialCacheNames(cacheNames)
    //初始化缓存配置
    .withInitialCacheConfigurations(configurationMap).build();

 }
}

编写service层

package org.example.base.service.impl;

import org.example.base.bean.Animal;
import org.example.base.service.AnimalService;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;

/**
 * @author l
 * @date Created in 2020/11/4 17:33
 */
@Service
@CacheConfig(cacheNames = "my-redis-cache1", cacheManager = "redisCacheManager")
public class AnimalServiceImpl implements AnimalService {

 @Override
 @Cacheable(key = "#id",sync = true)
 public Animal getAnimal(Integer id) {
  System.out.println("操作数据库，返回Animal");
  return new Animal(110, "cat", "fish");
 }

 /**
  * 使用@CachePut注解的方法，一定要有返回值，该注解声明的方法缓存的是方法的返回结果。
  * it always causes the
  * method to be invoked and its result to be stored in the associated cache
  **/
 @Override
 @CachePut(key = "#animal.getId()")
 public Animal setAnimal(Animal animal) {
  System.out.println("存入数据库");
  return animal;
 }

 @Override
 @CacheEvict(key = "#id")
 public void deleteAnimal(Integer id) {
  System.out.println("删除数据库中animal");
 }

 @Override
 @CachePut(key = "#animal.getId()")
 public Animal updateAnimal(Animal animal) {
  System.out.println("修改animal,并存入数据库");
  return animal;
 }

}

编写controller层

package org.example.base.controller;

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import lombok.extern.slf4j.Slf4j;
import org.example.base.bean.Animal;
import org.example.base.bean.User;
import org.example.base.service.AnimalService;
import org.example.base.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.cache.Cache;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * @author l
 * @date Created in 2020/10/23 15:46
 */
@Controller
@RequestMapping("/user")
@Slf4j
public class UserController {

 private AnimalService animalService;

 @Autowired
 public UserController(AnimalService animalService) {
  this.animalService = animalService;
 }

 @GetMapping("/queryAnimal")
 @ResponseBody
 public Animal queryAnimal(@RequestParam(value = "ID") Integer ID) {
  Animal animal = animalService.getAnimal(ID);
  log.info("animal " + animal.toString());
  return animal;
 }
}

配置jemeter

启动jemeter ,查看当前redis的客户端连接数

当前springboot lettuce连接池中有三个连接 加上当前查询窗口的连接，共计4个socket连接。

jemeter 运行2分钟后显示，平均响应时间为239，吞吐量为4158.2/sec

注释掉 RedisConfig 类中
genericObjectPoolConfig.setTimeBetweenEvictionRunsMillis(100);
这行代码，重新启动项目，用jemeter进行压测接口。
查看当前redis的客户端连接数

可以看出连接池没有生效，经过两分钟压测后显示平均响应时间为241，吞吐量为4139.2/sec

，接口性能相比于使用lettuce连接池中多个连接，略有下降。 总结 要想使lettuce连接池生效，即使用多个redis物理连接。这行设置不能缺少
genericObjectPoolConfig.setTimeBetweenEvictionRunsMillis(100); 这个设置是，每隔多少毫秒，空闲线程驱逐器关闭多余的空闲连接，且保持最少空闲连接可用，这个值最好设置大一点，否者影响性能。同时 genericObjectPoolConfig.setMinIdle(minIdle); 中minldle值要大于0。
lettuce连接池属性timeBetweenEvictionRunsMillis如果不设置 默认是 -1，当该属性值为负值时，lettuce连接池要维护的最小空闲连接数的目标minIdle就不会生效 。源码中的解释如下：

	/**
		 * Target for the minimum number of idle connections to maintain in the pool. This
		 * setting only has an effect if both it and time between eviction runs are
		 * positive.
		 */
		private int minIdle = 0;

factory.setShareNativeConnection(true)，shareNativeConnection 这个属性默认是true,允许多个连接公用一个物理连接。如果设置false ,每一个连接的操作都会开启和关闭socket连接。如果设置为false,会导致性能下降，本人测试过了。源码中解释如下：

/**
	 * Enables multiple {@link LettuceConnection}s to share a single native connection. If set to {@literal false}, every
	 * operation on {@link LettuceConnection} will open and close a socket.
	 *
	 * @param shareNativeConnection enable connection sharing.
	 */
	public void setShareNativeConnection(boolean shareNativeConnection) {
		this.shareNativeConnection = shareNativeConnection;
	}

-factory.setValidateConnection(false)， validateConnection这个属性是每次获取连接时，校验连接是否可用。默认false,不去校验。默认情况下，lettuce开启一个共享的物理连接，是一个长连接，所以默认情况下是不会校验连接是否可用的。如果设置true,会导致性能下降。

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