技術標籤：SpringCloudspring bootspring cloud

最近，使用Spring Cloud 2020.0.0-SNAPSHOT整合SpringBoot2.4.0、MyBatis Plus3.4.1搭建微服務，JDK版本是13.0.2。
啟動微服務應用時，出現一系列異常，重點羅列如下：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (
 
_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.0)

_ _   |_  _ _|_. ___ _ |    _ 
| | |\/|_)(_| | |_\  |_)||_|_\ 
     /               |         
                        3.4.1 

ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name '
 
xxxController': Unsatisfied dependency expressed through field 'xxxFeignService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.edee.xxx.xxx.feign.xxxFeignService': FactoryBean threw exception on object creation; nested exception is java.lang.IllegalStateException: No Feign Client for
 
 loadBalancing defined. Did you forget to include spring-cloud-starter-loadbalancer?

看到最後一句“Did you forget to include spring-cloud-starter-loadbalancer?”，立馬想到服務依賴是否缺少？於是，嘗試新增如下依賴：

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-loadbalancer</artifactId>
        </dependency>

重新啟動服務，上面的異常不見了。但又出現了新的：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-12-16 11:08:07.394 ERROR 32748 --- [           main] o.s.boot.SpringApplication               : Application run failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'growthChangeHistoryController': Unsatisfied dependency expressed through field 'growthChangeHistoryService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'growthChangeHistoryService': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.edee.xxx.xxx.dao.GrowthChangeHistoryDao' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

這個很讓人頭疼，百思不得其解！
懷著絕望的心情查閱網上各種資料，說法也是五花八門，一一嘗試，均不奏效。
但有些文章提到了版本相容問題，比如就有文章專門指出SpringBoot雖然已經發布了2.4.0版本，但是，不建議大家馬上升級，因為版本相容問題較多。
接下來嘗試把SpringBoot降級為2.1.13.RELEASE，重啟，又異常：

Caused by: org.springframework.core.NestedIOException: ASM ClassReader failed to parse class file - probably due to a new Java class file version that isn't supported yet: file ;
nested exception is java.lang.IllegalArgumentException: Unsupported class file major version 57

根據此異常，查到關鍵一篇部落格：https://www.cnblogs.com/INnoVationv2/p/12349571.html。裡面提到：jdk13暫時不被支援,降級至jdk11,可正常執行。
無奈，只能大換血，將JDK降為11.0.9。重啟，依然異常：

"C:\Program Files\Java\jdk-11.0.9\bin\java.exe" -XX:TieredStopAtLevel=1 -noverify -Dspring.output.ansi.enabled=always -Dcom.sun.management.jmxremote -Dspring.jmx.enabled=true -Dspring.liveBeansView.mbeanDomain -Dspring.application.admin.enabled=true "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA 2019.2.4\lib\idea_rt.jar=53833:C:\Program Files\JetBrains\IntelliJ IDEA 2019.2.4\bin" -Dfile.encoding=UTF-8 -classpath C:\Users\Administrator\AppData\Local\Temp\classpath336559354.jar com.edee.xxx.ware.xxxApplication
錯誤: 找不到或無法載入主類 com.edee.xxx.ware.xxxApplication
原因: java.lang.ClassNotFoundException: com.edee.xxx.ware.xxxApplication

幾近崩潰下，又嘗試降低Spring Cloud版本，由2020.0.0-SNAPSHOT降為Greenwich.SR6。這次，終於成功了！

最終版本組合：
Spring Cloud：Greenwich.SR6；
SpringBoot：2.1.13.RELEASE；
MyBatis Plus：3.4.1；
JDK：11.0.9。
但願該組合能夠穩如泰山啊！