redisTemplate注入失败

 在springboot项目中配置redis的时候，找了一个配置的工具类，连接如下：

https://www.cnblogs.com/zeng1994/p/03303c805731afc9aa9c60dbbd32a323.html

我复制了里面的config类和util类，但是是运行项目的时候出现了redisTemplate注入失败的问题，看评论也说到了这个问题，但是作者说“姿势有问题”，我也下载运行了作者提供的代码，居然运行成功了。(。>︿<)_θ

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-10-10 10:22:56.922 [restartedMain] ERROR org.springframework.boot.SpringApplication - Application run failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'testController': Unsatisfied dependency expressed through field 'redisUtil'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisUtil': 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/jack/big2watermelon/utils/redis/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$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596)
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1411)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:845)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:877)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:549)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:744)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:391)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:312)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1204)
	at com.jack.big2watermelon.Big2watermelonApplication.main(Big2watermelonApplication.java:10)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisUtil': 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/jack/big2watermelon/utils/redis/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.inject(AutowiredAnnotationBeanPostProcessor.java:596)
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1411)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:592)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1251)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1171)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593)
	... 24 common frames omitted
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisTemplate' defined in class path resource [com/jack/big2watermelon/utils/redis/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:769)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1321)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1160)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1251)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1171)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593)
	... 37 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:627)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:607)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1321)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1160)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1251)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1171)
	at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857)
	at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760)
	... 50 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory]: Factory method 'redisConnectionFactory' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:622)
	... 64 common frames omitted
Caused by: java.lang.NoClassDefFoundError: org/apache/commons/pool2/impl/GenericObjectPoolConfig
	at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration$LettucePoolingClientConfigurationBuilder.(LettucePoolingClientConfiguration.java:91)
	at org.springframework.data.redis.connection.lettuce.LettucePoolingClientConfiguration.builder(LettucePoolingClientConfiguration.java:50)
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$PoolBuilderFactory.createBuilder(LettuceConnectionConfiguration.java:141)
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.createBuilder(LettuceConnectionConfiguration.java:104)
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.getLettuceClientConfiguration(LettuceConnectionConfiguration.java:90)
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration.redisConnectionFactory(LettuceConnectionConfiguration.java:74)
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$$EnhancerBySpringCGLIB$$ad69a576.CGLIB$redisConnectionFactory$0()
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$$EnhancerBySpringCGLIB$$ad69a576$$FastClassBySpringCGLIB$$7cc66e8d.invoke()
	at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
	at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:363)
	at org.springframework.boot.autoconfigure.data.redis.LettuceConnectionConfiguration$$EnhancerBySpringCGLIB$$ad69a576.redisConnectionFactory()
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
	... 65 common frames omitted
Caused by: java.lang.ClassNotFoundException: org.apache.commons.pool2.impl.GenericObjectPoolConfig
	at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 81 common frames omitted

思考：

1.文章的评论里也说用@Resources这个注解来代替@Auotwired注解，但是作者表示这种做法虽然解决了问题，但是是不正确

2.根据可以成功运行作者给的代码来看，他本身的代码是没有问题的，但是我明明都把作者的代码复制，就是运行失败，为了发现问题究竟出现在哪里，我重新创建了新的springboot项目，发现了问题所在：

2.1这是作者提供的application.properties的文件配置

# Redis数据库索引（默认为0）
spring.redis.database=0
# Redis服务器地址
spring.redis.host=localhost
# Redis服务器连接端口
spring.redis.port=6379
# Redis服务器连接密码（默认为空）
spring.redis.password=
# 连接池最大连接数（使用负值表示没有限制）
spring.redis.pool.max-active=200
# 连接池最大阻塞等待时间（使用负值表示没有限制）
spring.redis.pool.max-wait=-1
# 连接池中的最大空闲连接
spring.redis.pool.max-idle=10
# 连接池中的最小空闲连接
spring.redis.pool.min-idle=0
# 连接超时时间（毫秒）
spring.redis.timeout=1000

下面是我自己的yml文件里配置

spring:
  redis:
    database: 1
    host: localhost
    port: 6379
    password: 
    lettuce:
      pool:
        max-active: 200
        max-wait: 10
        min-idle: 0
    timeout: 1000
      

在写我自己的配置文件的时候，我发现，现在如果直接写“spring.pool.max-active”的时候，就会提示报错，建议使用jedis的连接池，然后我又发现有用lettuce来连接的，比较了一下，lettuce是基于netty的，是多线程安全，由于传统的jedis，那好，就用lettuce，最后是形成我上面的这一段配置。

运行的时候出现了redisTemplate注入失败的问题，所以我尝试将lettuce修改到jedis，运行竟然成功了。其实在项目启动的时候，我们也可以看到一些蛛丝马迹：

2019-10-10 13:49:49.099  INFO 7748 --- [           main] c.j.myredisdemo.MyRedisDemoApplication   : Starting MyRedisDemoApplication on SJ-PC with PID 7748 (D:\programe\workSpace\MyRedisDemo\target\classes started by SJ-PC in D:\programe\workSpace\MyRedisDemo)
2019-10-10 13:49:49.102  INFO 7748 --- [           main] c.j.myredisdemo.MyRedisDemoApplication   : No active profile set, falling back to default profiles: default
2019-10-10 13:49:49.745  INFO 7748 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Multiple Spring Data modules found, entering strict repository configuration mode!
2019-10-10 13:49:49.747  INFO 7748 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data repositories in DEFAULT mode.
2019-10-10 13:49:49.772  INFO 7748 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 13ms. Found 0 repository interfaces.
2019-10-10 13:49:50.250  INFO 7748 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2019-10-10 13:49:50.274  INFO 7748 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-10-10 13:49:50.274  INFO 7748 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.26]
2019-10-10 13:49:50.395  INFO 7748 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-10-10 13:49:50.395  INFO 7748 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1248 ms
。。。。。。。。。。。。如果我输出了，说明自定义的redisTemplate实例化了。。。。。。。。。。。。。。。。
2019-10-10 13:49:50.827  INFO 7748 --- [           main] io.lettuce.core.EpollProvider            : Starting without optional epoll library
2019-10-10 13:49:50.829  INFO 7748 --- [           main] io.lettuce.core.KqueueProvider           : Starting without optional kqueue library
2019-10-10 13:49:52.756  INFO 7748 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2019-10-10 13:49:53.020  INFO 7748 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-10-10 13:49:53.023  INFO 7748 --- [           main] c.j.myredisdemo.MyRedisDemoApplication   : Started MyRedisDemoApplication in 4.332 seconds (JVM running for 5.797)
2019-10-10 13:50:05.623  INFO 7748 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-10-10 13:50:05.624  INFO 7748 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2019-10-10 13:50:05.631  INFO 7748 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 7 ms

在log的第12、13行也输出了lettuce相关的日志，简单一句话就是：在 Spring Boot 1.x 版本默认使用的是 jedis ，而在 Spring Boot 2.x 版本默认使用的就是Lettuce。所以这里会更加偏向于使用lettuce。

在我查找为什么redisTemplate会注入失败的时候，查到了一篇文章：

https://www.jianshu.com/p/feef1421ab0b

在这篇文章里面，作者也使用了一毛一样的config类（主要出现注入失败的地方就是在这个类中），而且看他的yml配置，也是使用了lettuce，那何不试一试呢？

然后我复制了他的config类（其实是一样的，但是他多了@AutoConfigureAfter这个注解），运行还是无法注入。然后我再去找不同，发现他多了一个依赖：

    org.apache.commons
    commons-pool2

（上面还注明了一定要添加orz）

添加以后，项目开始正常运行了。

 

总结

说了这么多，总结一下几种解决方案：

1.将RedisTemplate对象上的注解从@Autowired改到@Resource

2.在注入RedisTemplate的时候，将后面的带的“<>”里的参数去掉

以上的两种方案来自于

https://blog.csdn.net/zhaoheng314/article/details/81564166

我本人没有试过，不做评价

3.在yml或在properties文件中，把lettuce配置redis的相关代码改到jedis下（简单来说就是把lettuce这个单词改成jedis），或者直接去掉lettuce相关的配置，使用lettuce自动配置，一般情况下也够用了

4.添加依赖：

    org.apache.commons
    commons-pool2

在创建Springboot项目的时候，我们会添加spring-boot-starter-data-redis这个依赖，很可能会忽略上面这个，所以很多教程也会忽略掉，不仔细看就会报错。