动态mapper优先级问题
但是使用过程中发现一个问题，相关的issue链接：
https://gitee.com/VampireAchao/stream-query/issues/I6EJ27
在项目中已经定义了Mapper，如果在动态mapper已经注入的情况下，没法再通过Database.execute方法拿到，而是拿到的动态Mapper
进而导致大部分只要是基于execute方法的函数都是这样
于是为了解决这个问题，在DefaultSqlInjector处进行了处理
在io.github.vampireachao.stream.plugin.mybatisplus.engine.configuration.StreamPluginAutoConfiguration下，当前的代码如下：
package io.github.vampireachao.stream.plugin.mybatisplus.engine.configuration;
import com.baomidou.mybatisplus.core.injector.AbstractMethod;
import com.baomidou.mybatisplus.core.injector.DefaultSqlInjector;
import com.baomidou.mybatisplus.core.mapper.Mapper;
import com.baomidou.mybatisplus.core.metadata.TableInfo;
import com.baomidou.mybatisplus.core.metadata.TableInfoHelper;
import com.baomidou.mybatisplus.core.toolkit.ReflectionKit;
import io.github.vampireachao.stream.core.lambda.LambdaHelper;
import io.github.vampireachao.stream.core.reflect.ReflectHelper;
import io.github.vampireachao.stream.plugin.mybatisplus.Database;
import io.github.vampireachao.stream.plugin.mybatisplus.engine.enumration.SqlMethodEnum;
import io.github.vampireachao.stream.plugin.mybatisplus.engine.methods.SaveOneSql;
import io.github.vampireachao.stream.plugin.mybatisplus.engine.methods.UpdateOneSql;
import org.apache.ibatis.builder.MapperBuilderAssistant;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.core.annotation.Order;
import java.util.List;
/**
* MPSql注入
*
* @author VampireAchao Cizai_
*/
public class StreamPluginAutoConfiguration {
private static final String CURRENT_NAMESPACE = LambdaHelper.getPropertyName(TableInfo::getCurrentNamespace);
/**
* <p>defaultSqlInjector.</p>
*
* @return a {@link com.baomidou.mybatisplus.core.injector.DefaultSqlInjector} object
*/
@Bean
@Order
@ConditionalOnMissingBean(DefaultSqlInjector.class)
public DefaultSqlInjector defaultSqlInjector() {
return new DefaultSqlInjector() {
@Override
public List<AbstractMethod> getMethodList(Class<?> mapperClass, TableInfo tableInfo) {
List<AbstractMethod> methodList = super.getMethodList(mapperClass, tableInfo);
methodList.add(new SaveOneSql(SqlMethodEnum.SAVE_ONE_SQL.getMethod()));
methodList.add(new UpdateOneSql(SqlMethodEnum.UPDATE_ONE_SQL.getMethod()));
return methodList;
}
@Override
public void inspectInject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass) {
super.inspectInject(builderAssistant, mapperClass);
Class<?> modelClass = ReflectionKit.getSuperClassGenericType(mapperClass, Mapper.class, 0);
if (modelClass == null) {
return;
}
TableInfo tableInfo = TableInfoHelper.initTableInfo(builderAssistant, modelClass);
if (Database.isDynamicMapper(tableInfo.getCurrentNamespace()) &&
!mapperClass.getName().equals(tableInfo.getCurrentNamespace())) {
// 降低动态mapper优先级
ReflectHelper.setFieldValue(tableInfo, CURRENT_NAMESPACE, mapperClass.getName());
Database.getEntityMapperClassCache().put(modelClass, mapperClass);
}
}
};
}
}这里重写了inspectInject方法，判断了当前如果tableInfo内存入的是动态mapper，且两个mapper的类名不一致，则使用反射修改掉tableInfo的currentNamespace
进而使得优先获取到的是项目中的Mapper
相关的单元测试用例如下：
@Test
@SuppressWarnings("unchecked")
void testMapperPriority() {
try (SqlSession sqlSession = SqlHelper.sqlSession(UserInfo.class)) {
IMapper<UserInfo> userMapper = Database.getMapper(UserInfo.class, sqlSession);
MybatisMapperProxy<UserInfoMapper> userMapperProxy =
(MybatisMapperProxy<UserInfoMapper>) Proxy.getInvocationHandler(userMapper);
Class<UserInfoMapper> userMapperClass = ReflectHelper.getFieldValue(userMapperProxy, "mapperInterface");
Assertions.assertEquals(UserInfoMapper.class, userMapperClass);
Assertions.assertFalse(Database.isDynamicMapper(userMapperClass.getName()));
IMapper<RoleInfo> roleMapper = Database.getMapper(RoleInfo.class, sqlSession);
MybatisMapperProxy<? super IMapper<RoleInfo>> roleMapperProxy =
(MybatisMapperProxy<? super IMapper<RoleInfo>>) Proxy.getInvocationHandler(roleMapper);
Class<? super IMapper<RoleInfo>> roleMapperClass = ReflectHelper.getFieldValue(roleMapperProxy, "mapperInterface");
Assertions.assertTrue(Database.isDynamicMapper(roleMapperClass.getName()));
}
}此时的UserInfoMapper是项目中存在的
因为直接使用Database.getMapper获取到的是一个代理，所以使用了Proxy.getInvocationHandler(userMapper)以及反射获取mapperInterface属性来得到代理到的目标类型
两个mapper通过isDynamicMapper方法的对比：
不是动态Mapper
Assertions.assertFalse(Database.isDynamicMapper(userMapperClass.getName()));是动态Mapper
Assertions.assertTrue(Database.isDynamicMapper(roleMapperClass.getName()));本文参与 腾讯云自媒体分享计划，分享自作者个人站点/博客。
原始发表：2023-03-18，如有侵权请联系 cloudcommunity@tencent.com 删除
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