• 2CacheSpringRedisAutoConfiguration配置文件在RedisAutoConfiguration之后，J2CacheAutoConfiguration之前加载。
  • 通过j2cache.redis-client可以配置redis客户端：Jedis或则Lettuce,本次学习使用Lettuce。
  • 使用RedisStandaloneConfiguration构建LettuceConnectionFactory对象。
  • 最后将RedisTemplate的对象交给Spring管理。
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@Bean("j2CacheRedisTemplate")
public RedisTemplate<String, Serializable> j2CacheRedisTemplate(
  @Qualifier("j2CahceRedisConnectionFactory") RedisConnectionFactory j2CahceRedisConnectionFactory,
  @Qualifier("j2CacheValueSerializer") RedisSerializer<Object> j2CacheSerializer) {
  RedisTemplate<String, Serializable> template = new RedisTemplate<String, Serializable>();
  template.setKeySerializer(new StringRedisSerializer());
  template.setHashKeySerializer(new StringRedisSerializer());
  template.setDefaultSerializer(j2CacheSerializer);
  template.setConnectionFactory(j2CahceRedisConnectionFactory);
  return template;
}
//j2CahceRedisConnectionFactory为：LettuceConnectionFactory
//j2CacheSerializer为：J2CacheSerializer，底层使用net.oschina.j2cache.util.SerializationUtils#g_serializer
@Primary
@Bean("j2CahceRedisConnectionFactory")
public LettuceConnectionFactory lettuceConnectionFactory(net.oschina.j2cache.J2CacheConfig j2CacheConfig) {
  //简化了一下
  LettucePoolingClientConfiguration.LettucePoolingClientConfigurationBuilder config = LettucePoolingClientConfiguration.builder();
  config.commandTimeout(Duration.ofMillis(5000));
  config.poolConfig(getGenericRedisPool());
  RedisStandaloneConfiguration single = new RedisStandaloneConfiguration("xxxx", 6379);
  single.setDatabase(10);
  single.setPassword("****");
  LettuceConnectionFactory connectionFactory = new LettuceConnectionFactory(single, config.build());
  return connectionFactory;
}

再看RedisTemplate类：
img

RedisTemplate继承了RedisAccessor类，实现RedisOperations和BeanClassLoaderAware接口，其中RedisAccessor维护了redis连接工厂，RedisOperations定义redis相关操作。

这里的connectionFactory为LettuceConnectionFactory：操作Redis的准备工作

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private @Nullable AbstractRedisClient client;
private @Nullable LettuceConnectionProvider connectionProvider;
private @Nullable LettuceConnectionProvider reactiveConnectionProvider;

public void afterPropertiesSet() {
  //获取RedisClient客户端
  this.client = createClient();
  //org.springframework.data.redis.connection.lettuce.LettuceConnection#CODEC
  //ByteArrayCodec
  this.connectionProvider = new ExceptionTranslatingConnectionProvider(createConnectionProvider(client, CODEC));
  
  //org.springframework.data.redis.connection.lettuce.LettuceReactiveRedisConnection#CODEC
  //ByteBufferCodec
  this.reactiveConnectionProvider = new ExceptionTranslatingConnectionProvider(
    createConnectionProvider(client, LettuceReactiveRedisConnection.CODEC));
  
  //略
}
protected AbstractRedisClient createClient() {
  //略
  RedisURI uri = isDomainSocketAware()
    ? createRedisSocketURIAndApplySettings(((DomainSocketConfiguration) configuration).getSocket())
    : createRedisURIAndApplySettings(getHostName(), getPort());
  
  //clientConfiguration为：DefaultLettucePoolingClientConfiguration
  RedisClient redisClient = clientConfiguration.getClientResources() //
    .map(clientResources -> RedisClient.create(clientResources, uri)) //
    .orElseGet(() -> RedisClient.create(uri));
  clientConfiguration.getClientOptions().ifPresent(redisClient::setOptions);
  
  return redisClient;
}

  • 首先创建RedisClient客户端

  • 之后创建LettuceConnectionProvider，这里使用了装饰器模式：StandaloneConnectionProvider->LettucePoolingConnectionProvider->ExceptionTranslatingConnectionProvider，从名称上也能大概看出装-

    • StandaloneConnectionProvider：独立的获取redis连接，底层使用Netty框架。

  • LettucePoolingConnectionProvider：redis连接池化技术，使用org.apache.commons.pool2.impl.GenericObjectPool

  • ExceptionTranslatingConnectionProvider：Redis连接异常转换。