NoClassDefFoundError：GenericObjectPoolConfig 问题

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记录一个redis的异常，今天更新测试环境的服务，该服务中使用了 spring-boot-starter-data-redis 的依赖，在发布测试的时候报错了，很尴尬。为啥呢，我本地运行的好好的呀。。。（是不是你的日常？😂）。

这个错的具体信息如下：

     6    2021-06-22 09:23:17,291 [application-name] [main] WARN  o.s.b.w.s.c.AnnotationConfigServletWebServerApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'redisConnectionFactory' defined in class path resource [org/springframework/boot/autoconfigure/data/redis/LettuceConnectionConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory]: Factory method 'redisConnectionFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
     7    2021-06-22 09:23:17,343 [application-name] [main] ERROR o.s.b.SpringApplication - Application run failed
     8    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'redisConnectionFactory' defined in class path resource [org/springframework/boot/autoconfigure/data/redis/LettuceConnectionConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory]: Factory method 'redisConnectionFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
     9        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:657)
    10        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:637)
    11        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1341)
    12        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1181)
    13        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:556)
    14        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:516)
    15        at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:324)
    16        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)
    17        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:322)
    18        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    19        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:897)
    20        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:879)
    21        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:551)
    22        at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:143)
    23        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758)
    24        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750)
    25        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:405)
    26        at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
    27        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237)
    28        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
    29        at com.ichinae.imis.MgrApplication.main(MgrApplication.java:20)
    30        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    31        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    32        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    33        at java.lang.reflect.Method.invoke(Method.java:498)
    34        at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49)
    35        at org.springframework.boot.loader.Launcher.launch(Launcher.java:107)
    36        at org.springframework.boot.loader.Launcher.launch(Launcher.java:58)
    37        at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88)
    38    Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory]: Factory method 'redisConnectionFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
    39        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
    40        at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:652)
    41        ... 28 common frames omitted
    42    Caused by: java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
    43        at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration$LettucePoolingClientConfigurationBuilder.<init>(LettucePoolingClientConfiguration.java:94)
    44        at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration.builder(LettucePoolingClientConfiguration.java:51)
    45        at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$PoolBuilderFactory.createBuilder(LettuceConnectionConfiguration.java:159)
    46        at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.createBuilder(LettuceConnectionConfiguration.java:107)
    47        at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.getLettuceClientConfiguration(LettuceConnectionConfiguration.java:92)
    48        at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.redisConnectionFactory(LettuceConnectionConfiguration.java:74)
    49        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    50        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    51        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    52        at java.lang.reflect.Method.invoke(Method.java:498)
    53        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
    54        ... 29 common frames omitted
    55    Caused by: java.lang.ClassNotFoundException: org.apache.commons.pool2.impl.GenericObjectPoolConfig
    56        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    57        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    58        at org.springframework.boot.loader.LaunchedURLClassLoader.loadClass(LaunchedURLClassLoader.java:151)
    59        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    60        ... 40 common frames omitted

像往常一样，copy 异常信息，粘贴的google搜一下，然后介绍的都是价格以apache common pool2 的依赖，然后还有竟然说重建一个项目到。。。（兄弟你搞笑的吧🙄）。

来说下这个异常的原因，报这个错的去看下你的配置文件中是不是配置了 lettuce.pool 的配置信息，
如果有那就对了，解决的方法有两个：

1. 因为启动时来加载器找不到common-pool2的相关类，那么就给它把相关类引入，添加依赖：

   <dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
   </dependency>

2. 移除lettuce.pool的配置，如果你都用不到，或者都是复制过来的配置，就用默认的就可以，删除这个相关配置。