SB了!给注解的数组属性赋值，我竟然...

项目中用到了mybatis-plus。springboot集成mybatis-plus项目，通常会使用内置mybatis工具包的org.mybatis.spring.annotation.MapperScan注解，来完成Mapper类的扫描。MapperScan注解源码见下。

public @interface MapperScan {
 
  /**
   * Alias for the {@link #basePackages()} attribute. Allows for more concise
   * annotation declarations e.g.:
   * {@code @MapperScan("org.my.pkg")} instead of {@code @MapperScan(basePackages = "org.my.pkg"})}.
   *
   * @return base package names
   */
  String[] value() default {};
 
  /**
   * Base packages to scan for MyBatis interfaces. 
   * Note that only interfaces with at least one method will be registered; concrete classes will be ignored.
   * 翻译：用于扫描MyBatis接口的基础package（可多个）。请注意，只有具有至少一个方法的接口才会被注册；具体类将被忽略。
   *
   * @return base package names for scanning mapper interface
   */
  String[] basePackages() default {};
}

项目使用这个MapperScan注解来决定扫描Mapper类所在的包。见下方MybatisPlusConfig配置类。

package springtrans;
 
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
 
@Configuration
@MapperScan(value={"springtrans.**.mapper"})
public class MybatisPlusConfig {
 
    /**
         *  分页插件
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        // 设置sql的limit为无限制，默认是500
        return new PaginationInterceptor().setLimit(-1);
    }
   
}

近期在对项目中的结算代码进行优化，这里，我们先设定结算表仓储类名称是SettlementMapper。这次重构涉及到需要屏蔽SettlementMapper的update操作。实现途径是将SettlementMapper从现有package移出去，并且让mybatis-plus追加扫描SettlementMapper所在的package。

于是，修改MybatisPlusConfig中MapperScan的value值。

@Configuration
@MapperScan(value={"springtrans.**.mapper, springtrans.transtest.manager"})
public class MybatisPlusConfig {
   ...
}

不料，运行testcase出现了下面的NoSuchBeanDefinitionException异常。

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'springtrans.transtest.entity.OrderMapper' available: 
expected at least 1 bean which qualifies as autowire candidate. 
Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1695)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1253)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207)
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:636)
	... 44 more

聪明的你，是不是看出了其中的端倪？

哈哈，我竟然犯了如此低级失误。
正确姿势是：

@Configuration
@MapperScan(value={"springtrans.**.mapper", "springtrans.transtest.manager"})
public class MybatisPlusConfig {
   ...
}

EOF，感谢阅读！