redis遇到 Unsatisfied dependency expressed through field ‘redisTemplate‘；

遇到这个问题的解决方式

Error creating bean with name 'cacheService': Unsatisfied dependency expressed through field 'redisTemplate'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisTemplate' defined in class path resource

解决方式：

从错误日志来看，你的应用程序在尝试创建 redisTemplate Bean 时遇到了问题，具体原因是缺少了 org.apache.commons.pool2.impl.GenericObjectPoolConfig 类。这个类是 Apache Commons Pool 库的一部分，通常用于管理对象池，而在 Redis 的情况下，它被用来管理连接池。

错误原因

java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig 表明在运行时找不到 GenericObjectPoolConfig 类。这通常是由于缺少必要的依赖库或者依赖版本不兼容导致的。

解决方案

要解决这个问题，你需要确保项目中包含了 commons-pool2 依赖，并且它的版本与你使用的其他依赖（如 Spring Data Redis 和 Lettuce）兼容。

1. 添加 `commons-pool2` 依赖

在 pom.xml 文件中添加 commons-pool2 依赖：

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
    <version>2.11.1</version> <!-- 请根据需要选择合适的版本 -->
</dependency>

如果你使用的是 Spring Boot 2.x 版本，通常不需要显式指定 commons-pool2 的版本，因为 Spring Boot 会自动为你管理依赖版本。你可以直接添加以下依赖：

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

2. 检查依赖冲突

有时候，依赖冲突也会导致类似的问题。你可以使用 Maven 或 Gradle 的依赖树命令来检查是否有冲突的依赖。

Maven:
```
mvn dependency:tree
```
Gradle:
```
./gradlew dependencies
```

确保 commons-pool2 没有被其他依赖覆盖或替换为不兼容的版本。

3. 清理和重新构建项目

有时候，IDE 或构建工具可能会缓存旧的依赖。你可以尝试清理项目并重新构建：

Maven:
```
mvn clean install
```
Gradle:
```
./gradlew clean build
```

4. 检查 Redis 连接配置

虽然 NoClassDefFoundError 通常是由依赖问题引起的，但也不排除 Redis 连接配置有问题的可能性。确保你在 application.yml 或 application.properties 中正确配置了 Redis 的连接信息，例如主机、端口、密码等。

5. 确保 Redis 服务器正常运行

最后，确保你的 Redis 服务器正在运行并且可以从应用程序所在的机器访问。你可以尝试使用 redis-cli 或其他工具连接到 Redis 服务器，以确认其状态。

总结

通过添加 commons-pool2 依赖并确保没有依赖冲突，你应该能够解决 NoClassDefFoundError 问题。如果问题仍然存在，请仔细检查项目的依赖配置和 Redis 连接设置。

以下为报错全文：

2025-01-04 18:36:05.560 ERROR 15784 --- [           main] o.s.boot.SpringApplication               : Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'cacheService': Unsatisfied dependency expressed through field 'redisTemplate'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisTemplate' defined in class path resource [com/digitalcollectibles/util/RedisConfig.class]: Unsatisfied dependency expressed through method 'redisTemplate' parameter 0; nested exception is 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
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:660) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1413) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:601) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:944) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-5.3.6.jar:5.3.6]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583) ~[spring-context-5.3.6.jar:5.3.6]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:144) ~[spring-boot-2.4.5.jar:2.4.5]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:782) [spring-boot-2.4.5.jar:2.4.5]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:774) [spring-boot-2.4.5.jar:2.4.5]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:439) [spring-boot-2.4.5.jar:2.4.5]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:339) [spring-boot-2.4.5.jar:2.4.5]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1340) [spring-boot-2.4.5.jar:2.4.5]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1329) [spring-boot-2.4.5.jar:2.4.5]
	at com.digitalcollectibles.Application.main(Application.java:14) [classes/:na]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisTemplate' defined in class path resource [com/digitalcollectibles/util/RedisConfig.class]: Unsatisfied dependency expressed through method 'redisTemplate' parameter 0; nested exception is 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
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:800) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:541) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1334) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:564) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1380) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1300) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:657) ~[spring-beans-5.3.6.jar:5.3.6]
	... 21 common frames omitted
Caused by: 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
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:658) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:638) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1334) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:564) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:524) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1380) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1300) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:887) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:791) ~[spring-beans-5.3.6.jar:5.3.6]
	... 34 common frames omitted
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
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.3.6.jar:5.3.6]
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:653) ~[spring-beans-5.3.6.jar:5.3.6]
	... 48 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
	at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration$LettucePoolingClientConfigurationBuilder.<init>(LettucePoolingClientConfiguration.java:94) ~[spring-data-redis-2.4.8.jar:2.4.8]
	at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration.builder(LettucePoolingClientConfiguration.java:51) ~[spring-data-redis-2.4.8.jar:2.4.8]
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$PoolBuilderFactory.createBuilder(LettuceConnectionConfiguration.java:172) ~[spring-boot-autoconfigure-2.4.5.jar:2.4.5]
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.createBuilder(LettuceConnectionConfiguration.java:110) ~[spring-boot-autoconfigure-2.4.5.jar:2.4.5]
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.getLettuceClientConfiguration(LettuceConnectionConfiguration.java:95) ~[spring-boot-autoconfigure-2.4.5.jar:2.4.5]
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.redisConnectionFactory(LettuceConnectionConfiguration.java:77) ~[spring-boot-autoconfigure-2.4.5.jar:2.4.5]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_381]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_381]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_381]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_381]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154) ~[spring-beans-5.3.6.jar:5.3.6]
	... 49 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.apache.commons.pool2.impl.GenericObjectPoolConfig
	at java.net.URLClassLoader.findClass(URLClassLoader.java:387) ~[na:1.8.0_381]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:418) ~[na:1.8.0_381]
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355) ~[na:1.8.0_381]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:351) ~[na:1.8.0_381]
	... 60 common frames omitted

与目标 VM 断开连接, 地址为: ''127.0.0.1:61438'，传输: '套接字''