Spring Boot如果Redis宕机将无法启动。

Question

Redis在我的应用程序中是可选的，并且这是一个要求，即使Redis宕机，应用程序必须能够无问题地启动。
我能够使用“spring-data-redis”1.8.1版本来处理这个问题，但当我升级到2.0.1时，它会引起问题。
我能够捕获LettuceConnectionFactory抛出的异常，但现在它也会抛出异常并且控制不会返回到调用类。
请告诉我如何使Redis bean实例化是可选的，以便即使Redis宕机，应用服务器也可以无问题地启动。

SpringRedisConfig.java

   @Configuration
    public class SpringRedisConfig{
        private static final Logger logger = LoggerFactory.getLogger(SpringRedisConfig.class);

        @Value("${redis.config.file.path}")
        private String redisConfigFilePath;

        @Value("${redis.timeout}")
        private long redisTimeOut;

        public @Bean RedisTemplate redisTemplate(){
            RedisTemplate<String, Object> redisTemplate = null;
            try {
                redisTemplate = new RedisTemplate<>();
                redisTemplate.setKeySerializer(new StringRedisSerializer());
                redisTemplate.setHashKeySerializer(new StringRedisSerializer());
                redisTemplate.setHashValueSerializer(new GenericToStringSerializer<>(Long.class));
                redisTemplate.setConnectionFactory(connectionFactory());
            }catch(Exception e){
                logger.error("Error getting Redis Template connection ",e);
            }
            return redisTemplate;
        }

        @Bean
        public LettuceConnectionFactory connectionFactory() {
            LettuceConnectionFactory connectionFactory = null;
            try {
                ClientOptions clientOptions = ClientOptions.builder()
                        .cancelCommandsOnReconnectFailure(true)
                        .disconnectedBehavior(ClientOptions.DisconnectedBehavior.REJECT_COMMANDS)
                        .build();
                RedisStandaloneConfiguration standaloneConfig = new RedisStandaloneConfiguration("localhost",
                        6379);
                LettuceClientConfiguration lettuceClientConfiguration = LettuceClientConfiguration.builder().clientOptions(clientOptions).build();
                connectionFactory = new LettuceConnectionFactory(standaloneConfig, lettuceClientConfiguration);
            }catch(Exception e){
                logger.error("Error ",e);
            }
            return connectionFactory;
        }
    }

控制台输出：

main] o.s.boot.SpringApplication               : Application startup failed

    org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisCacheManagerController': Unsatisfied dependency expressed through field 'redisCacheManagerProvider'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisCacheManagerProvider': Unsatisfied dependency expressed through field 'redisTemplate'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'redisTemplate' defined in class path resource [com/kohls/jsl/cache/provider/config/SpringRedisConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: RedisConnectionFactory is required
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
        at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.8.RELEASE.jar:1.5.8.RELEASE]
        at com.kohls.browse.Application.main(Application.java:35) [classes/:na]
    Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'redisCacheManagerProvider': Unsatisfied dependency expressed through field 'redisTemplate'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'redisTemplate' defined in class path resource [com/kohls/jsl/cache/provider/config/SpringRedisConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: RedisConnectionFactory is required
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        ... 19 common frames omitted
    Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'redisTemplate' defined in class path resource [com/kohls/jsl/cache/provider/config/SpringRedisConfig.class]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: RedisConnectionFactory is required
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        ... 32 common frames omitted
    Caused by: java.lang.IllegalStateException: RedisConnectionFactory is required
        at org.springframework.util.Assert.state(Assert.java:70) ~[spring-core-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.data.redis.core.RedisAccessor.afterPropertiesSet(RedisAccessor.java:38) ~[spring-data-redis-2.0.1.RELEASE.jar:2.0.1.RELEASE]
        at org.springframework.data.redis.core.RedisTemplate.afterPropertiesSet(RedisTemplate.java:123) ~[spring-data-redis-2.0.1.RELEASE.jar:2.0.1.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) ~[spring-beans-4.3.12.RELEASE.jar:4.3.12.RELEASE]
        ... 42 common frames omitted

- Renu

Answer 1

快速解决方案： 在Spring初始化期间，只需捕获错误并返回null。如果由于任何原因Redis宕机，则它将返回null。虽然不建议捕获 Error，但你可以在技术上捕获它。如果你计划将null作为后备选项返回，则必须确保所有依赖服务都是null安全的。你也可以考虑返回一个模拟对象。

@Bean 
public RedisTemplate redisTemplate(){          
RedisTemplate<String, Object> redisTemplate = null;
try {
    redisTemplate = new RedisTemplate<>();
    redisTemplate.setKeySerializer(new StringRedisSerializer());
    redisTemplate.setHashKeySerializer(new StringRedisSerializer());
    redisTemplate.setHashValueSerializer(new GenericToStringSerializer<>(Long.class));
    redisTemplate.setConnectionFactory(connectionFactory());
}catch(**Error** e){
    logger.error("Error getting Redis Template connection ",e);
}
return redisTemplate;
}

首选解决方案： 根据应用程序配置使用不同的Spring Boot配置。您可以在此处了解有关spring boot配置文件的更多信息：此处。您可以为开发配置设置不同的bean配置，并仅模拟所需的服务，而无需实际连接到Redis实例。您还可以有条件地编写逻辑。如果Redis服务正常运行，则返回实际实例或返回模拟对象。

潜在地，您可以在不使用配置文件的情况下返回模拟对象，但这并不推荐。配置文件将提供逻辑隔离，以便您不会意外地在生产环境中启用此类逻辑。

以下是示例代码，只是为了提供一些思路。 ActualRedisService 和 MockedRedisService 将实现公共接口 RedisService。

MockedRedisService 服务将具有没有实现的简单方法，而 ActualRedisService 将连接到实际的 Redis 实例。

@Bean 
@Profile("dev")
public RedisService redisService(){
  if(isEveryThingOkWithRedis()){
    return new ActualRedisService();
  }
  return new MockedRedisService();
}
   

我希望你能帮到您。

- Lokesh