• The bean ‘xx.FeignClientSpecification’ could not be registered. A bean with that name has already been defined and overriding is disabled.

    image.png

    起因：springboot从1.5升级到2.2.4
    原因：在使用相同名称的FeigClient注解时，注入到Ioc的是相同Bean名。所以错误是由FeignClientSpecification类引起的
    解决：添加如下配置，在spring boot2.1之前该配置默认为true，2.1开始默认false，更好的解决方案是尽量取消相同命名

    1. spring:     
    2.     main:
    3.     allow-bean-definition-overriding: true
    • java.lang.ClassNotFoundException: org.springframework.boot.autoconfigure.jdbc.metadata.DataSourcePoolMetadataProvider

    起因：springboot 1.x升级到 2.x
    原因：druid数据源版本不兼容
    解决：升级版本到1.1.10

    1.         <dependency>
    2.             <groupId>com.alibaba</groupId>
    3.             <artifactId>druid-spring-boot-starter</artifactId>
    4.             <version>1.1.10</version>
    5.         </dependency>
    • java.sql.SQLException: The server time zone value ‘?й???׼ʱ?’ is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the ‘serverTimezone’ configuration property) to use a more specifc time zone value if you want to utilize time zone support.

    image.png

    起因：springboot1.x 升级到 2.x
    原因：版本不兼容，显示新版本的数据库连接程序需要指定UTC时区
    解决：改正方法将配置文件中的“url”后面加上指定的时区，&serverTimezone=GMT

    1. <!--改之前-->
    2. jdbc.driverClass   = com.mysql.cj.jdbc.Driver
    3. jdbc.url = jdbc:mysql://127.0.0.1:3306/db?useUnicode=true&characterEncoding=utf8
    4. jdbc.username = root
    5. jdbc.password = root123
    7. <!--改之后-->
    8. jdbc.driverClass   = com.mysql.cj.jdbc.Driver
    9. jdbc.url = jdbc:mysql://127.0.0.1:3306/db?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT
    10. jdbc.username = root
    11. jdbc.password = root123
    • Bean with name ‘xxx’ has been injected into other beans [xxx] in its raw version as part of a circular reference

    image.png

    Caused by: org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name ‘homeworkSubmitServiceImpl’: Bean with name ‘homeworkSubmitServiceImpl’ has been injected into other beans [homeworkEvaluateServiceImpl] in its raw version as part of a circular reference, but has eventually been wrapped. This means that said other beans do not use the final version of the bean. This is often the result of over-eager type matching - consider using ‘getBeanNamesOfType’ with the ‘allowEagerInit’ flag turned off, for example.

    起因：
    原因：springIoC异常，循环依赖，即A注入了B，B又注入了A，导致异常
    解决：使用@Lazy注解，取消注入预初始化，或使用setter方法注入

    • Configuration property name ‘sharding.jdbc.datasource.xiao_comment’ is not valid:

    Invalid characters: ‘_’
    Bean: servletEndpointRegistrar
    Reason: Canonical names should be kebab-case (‘-‘ separated), lowercase alpha-numeric characters and must start with a letter

    image.png

    起因：springboot 1.x升级到 2.x
    原因：springboot2.x造成，sharding jdbc建议使用-代替_，不支持下划线命名
    image.png
    解决：修改命名