结论：如果自定义了一个名为redisTemplate的bean,则会替换掉自动装配的RedisTemplate Bean.如果名字不是redisTemplate,则会在容器中同时存在自定义的RedisTemplate实例和默认自动装配的RedisTemplate实例。所以在Autowired注解最好配合@Qualifier注解一起使用，以明确使用的是那个RedisTemplate的实例。
同时，Spring boot还会默认装配一个StringRedisTemplate类型的Bean.
RedisAutoConfiguration类的源码：
package org.springframework.boot.autoconfigure.data.redis;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnSingleCandidate;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisOperations;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
@Import({ LettuceConnectionConfiguration.class, JedisConnectionConfiguration.class })
public class RedisAutoConfiguration {
@Bean
@ConditionalOnMissingBean(name = "redisTemplate")
@ConditionalOnSingleCandidate(RedisConnectionFactory.class)
public RedisTemplate redisTemplate(RedisConnectionFactory redisConnectionFactory) {
RedisTemplate template = new RedisTemplate<>();
template.setConnectionFactory(redisConnectionFactory);
return template;
}
@Bean
@ConditionalOnMissingBean
@ConditionalOnSingleCandidate(RedisConnectionFactory.class)
public StringRedisTemplate stringRedisTemplate(RedisConnectionFactory redisConnectionFactory) {
return new StringRedisTemplate(redisConnectionFactory);
}
}
可以从第一个Bean中使用的注解@ConditionalOnMissingBean(name = “redisTemplate”)来证明上述结论。
Spring boot 官方文档里的一段：
If you add your own @Bean of any of the auto-configured types, it replaces the default (except in the case of RedisTemplate, when the exclusion is based on the bean name, redisTemplate, not its type).
通常情况下，你配置某个类型的Bean,它就会替代系统默认装配的那个类型的Bean,
但是，对RedisTemplate是例外，你只有配置了名字为redisTemplate的Bean,它才会替代系统自动装配的类型为RedisTemplate的Bean
