mybatis-plus在使用多個mapper時報錯

報錯內容如下

Field baseMapper in com.baomidou.mybatisplus.extension.service.impl.ServiceImpl required a single bean, but xxx were found:
- xxxAMapper: defined in file [D:\xxx\AMapper.class]
- xxxBMapper: defined in file [D:\xxx\BMapper.class]
- xxxCMapper: defined in file [D:\xxx\CMapper.class]

Action:

Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed

Process finished with exit code 1

報錯原因分析

1.很多service繼承了com.baomidou.mybatisplus.extension.service.impl.ServiceImpl
2.很多mapper繼承了com.baomidou.mybatisplus.core.mapper.BaseMapper

service中使用getBaseMapper().insert(entity)等內置方法時候，會跳轉到ServiceImpl中的getBaseMapper()方法（如下圖所示）
報錯點：
baseMapper不知道到底要獲取哪一個繼承他的mapper，到底要查哪個實體類的表，因爲沒有明確指明，就會報這個錯。
修改思路：
繼承IService和ServiceImpl的時候要能明確的指向對應的mapper類纔行，就是要繼承的時候一定要指定泛型

報錯前我的Application,Service和Mapper文件如下

@SpringBootApplication
@MapperScan(value={"cn.com.test.mapper"})
public class MyApplication {

	public static void main(String[] args) {
		SpringApplication.run(MyApplication.class, args);
	}

}


//AService文件
public class AServiceImpl extends BaseServiceImpl {

}

public interface IAService extends IBaseService {

}
//Amapper文件
@Mapper
public interface AMapper extends BaseMapper<A> {

}
--------------------------------------------------------------
//BService文件
public class BServiceImpl extends BaseServiceImpl {

}

public interface IBService extends IBaseService {

}
//Bmapper文件
@Mapper
public interface BMapper extends BaseMapper<B> {

}
----------------------------------------------------------
//公共類
public class BaseServiceImpl<T extends Object> extends ServiceImpl implements IBaseService<T> { 
 }
public interface IBaseService<T extends Object> {
}

修改成功後我的Application,Service和Mapper文件如下

@SpringBootApplication
@MapperScan(value={"cn.com.test.mapper","com.baomidou.mybatisplus.core.mapper"})
public class MyApplication {

	public static void main(String[] args) {
		SpringApplication.run(MyApplication.class, args);
	}

}


//AService文件
public class AServiceImpl extends BaseServiceImpl<A> {

}

public interface IAService extends IBaseService<A> {

}
//Amapper文件
@Mapper
public interface AMapper extends BaseMapper<A> {

}
--------------------------------------------------------------
//BService文件
public class BServiceImpl extends BaseServiceImpl<B> {

}

public interface IBService extends IBaseService<B> {

}
//Bmapper文件
@Mapper
public interface BMapper extends BaseMapper<B> {

}
----------------------------------------------------------
//公共類
public class BaseServiceImpl<T extends Object> extends ServiceImpl implements IBaseService<T> { 
 }
public interface IBaseService<T extends Object> {
}

修改的點

1.MyApplication的MapperScan添加了com.baomidou.mybatisplus.core.mapper這個掃描範圍，這是mybatis-plus的BaseMapper所在的包位置
2.service繼承的時候指定對應的泛型，這樣是爲了能讓BaseMapper找到該映射的mapper，從而執行對應的mapper下的內置sql

你們沒有像我這樣公共類BaseServiceImpl這些，可以這樣寫

//AService文件
public class AServiceImpl extends ServiceImpl<AMapper ,A> {

}

public interface IAService extends IService<A>  {

}
//Amapper文件
@Mapper
public interface AMapper extends BaseMapper<A> {

}
---------------------------------------------------------------------------------------------------------

//BService文件
public class BServiceImpl extends ServiceImpl<BMapper ,B> {

}

public interface IBService extends IService<B> {

}
//Bmapper文件
@Mapper
public interface BMapper extends BaseMapper<B> {

}