本文背景：

1. RedisDesktopManager 能够连接正常，在 java 项目中报错

	at org.springframework.data.redis.connection.lettuce.StandaloneConnectionProvider.lambda$getConnection$1(StandaloneConnectionProvider.java:115) ~[spring-data-redis-2.6.1.jar:2.6.1]
	at java.util.Optional.orElseGet(Optional.java:267) ~[?:1.8.0_171]
	at org.springframework.data.redis.connection.lettuce.StandaloneConnectionProvider.getConnection(StandaloneConnectionProvider.java:115) ~[spring-data-redis-2.6.1.jar:2.6.1]
	at org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory$ExceptionTranslatingConnectionProvider.getConnection(LettuceConnectionFactory.java:1595) ~[spring-data-redis-2.6.1.jar:2.6.1]
	... 77 more
Caused by: io.lettuce.core.RedisCommandExecutionException: NOAUTH Authentication required.

分析处理：

  既然工具连接正常，那肯定是 java maven 项目中的依赖出了问题

  使用比较新的 springboot version = 2.6.3 ，经不断尝试降到 2.3.6.RELEASE 此问题消失

不降版本的处理方案：

1. 有部分场景不能降低版本，可参考文章  SpringBoot升级后连接不上Redis问题

import io.lettuce.core.ClientOptions;
import io.lettuce.core.protocol.ProtocolVersion;
import org.springframework.boot.autoconfigure.data.redis.LettuceClientConfigurationBuilderCustomizer;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.lettuce.LettuceClientConfiguration;


@Configuration
public class SpringRedisConfig implements LettuceClientConfigurationBuilderCustomizer {

    @Override
    public void customize(LettuceClientConfiguration.LettuceClientConfigurationBuilder clientConfigurationBuilder) {
        clientConfigurationBuilder.clientOptions(ClientOptions.builder()
                .protocolVersion(ProtocolVersion.RESP2)
                .build());
    }
}

2.使用 jedis ，排除 lettuce-core 的相关包