Add setter for mybatisMapperRegistry to support @DataPermission extensions

[192902649]

About the Bug...

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of MyBatis.

• I have confirmed this bug reproduces without 3rd party extensions (e.g. mybatis-plus).

Database Version

mysql

JDBC Driver Version

mysql

Issue Description

We plan to add an extension to MyBatis to handle the @DataPermission annotation on each Mapper's mappedStatement. Currently, mybatisMapperRegistry in MybatisConfiguration does not provide a set method, so it is not possible to directly customize the registry to store annotation information. At present, the only feasible approach is to modify this property via reflection, which is not very elegant. Could a setMybatisMapperRegistry method be provided in a future version to allow more flexible extensions?

public class DataPermissionConfigurationCustomizer implements ConfigurationCustomizer {

/**
 * Customize the given a {@link MybatisConfiguration} object.
 *
 * @param configuration the configuration object to customize
 */
@Override
public void customize(MybatisConfiguration configuration) {

    try {
        Field field = MybatisConfiguration.class.getDeclaredField("mybatisMapperRegistry");
        field.setAccessible(true);
        MapperRegistry original = (MapperRegistry) field.get(configuration);

        // 替换为我们自己的
        DataPermissionMybatisMapperRegistry custom = new DataPermissionMybatisMapperRegistry(configuration);
        field.set(configuration, custom);

        System.out.println("✅ MybatisMapperRegistry 已替换为 DataPermissionMapperRegistry");
    } catch (Exception e) {
        throw new RuntimeException("替换 MapperRegistry 失败", e);
    }
}

}

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[harawata]

Hello, @192902649 .

There is no MybatisConfiguration in this project (or other subproject of this organization), it seems.
Wrong project maybe?

[192902649]

Since the native Configuration class in MyBatis does not expose a public modification entry for mapperRegistry (i.e., no setter method is provided), MyBatis Plus replaces the original mapperRegistry with a custom implementation (MybatisMapperRegistry) when extending Configuration (MybatisConfiguration), in order to enhance Mapper registration and management capabilities.

Building on this mechanism, our system introduces additional business-driven requirements for further customization of the Mapper registration logic while using MyBatis Plus. Specifically, our current business scenario requires enforcing SQL data access scopes based on a custom annotation (@DataPermission). As this data permission logic must take effect during the Mapper parsing and registration phase, it is necessary to extend or replace the underlying MapperRegistry.

From an architectural evolution perspective, this approach represents consecutive modifications to a core component that MyBatis was not originally designed to be extensible—first by MyBatis Plus, and then by our business logic. While this solution satisfies the business requirements, it also requires careful consideration of compatibility, stability, and long-term maintenance risks across MyBatis and MyBatis Plus version upgrades.

`package com.yansen.framework.datapermission.registry.mybatis;

import com.baomidou.mybatisplus.core.MybatisMapperRegistry;
import com.yansen.framework.datapermission.annotation.DataPermission;
import com.yansen.framework.datapermission.rule.DataPermissionRule;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.ibatis.session.Configuration;
import org.springframework.core.annotation.AnnotationUtils;

import java.lang.reflect.Method;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;

public class DataPermissionMybatisMapperRegistry extends MybatisMapperRegistry {

/**
 * key: mappedStatementId
 *
 */
private static final Map<String, DataPermission> MAPPED_STATEMENT_PERMISSION_MAP = new ConcurrentHashMap<>();

/**
 * 数据权限规则数组
 */
private List<DataPermissionRule> rules;


public DataPermissionMybatisMapperRegistry(Configuration config, List<DataPermissionRule> rules) {
    super(config);
    this.rules = rules;
}

/**
 * @param type
 * @param <T>
 */
@Override
public <T> void addMapper(Class<T> type) {
    super.addMapper(type);
    DataPermission classAnnotation = AnnotationUtils.findAnnotation(type, DataPermission.class);
    for (Method method : type.getMethods()) {
        // 操作是否有这个注解
        DataPermission methodAnnotation = AnnotationUtils.findAnnotation(method, DataPermission.class);

        if (methodAnnotation == null) {
            methodAnnotation = classAnnotation;
        }
        if (methodAnnotation != null) {
            // 添加进去
            final String mappedStatementId = type.getName() + "." + method.getName();
            MAPPED_STATEMENT_PERMISSION_MAP.put(mappedStatementId, methodAnnotation);
        }

    }
}


public DataPermission getDataPermission(String mappedStatementId) {

    return MAPPED_STATEMENT_PERMISSION_MAP.get(mappedStatementId);
}

public List<DataPermissionRule> getDataPermissionRule(String mappedStatementId) {
    // 1. 无数据权限
    if (CollectionUtils.isEmpty(rules)) {
        return Collections.emptyList();
    }
    // 2. 未配置，则默认开启
    DataPermission dataPermission = getDataPermission(mappedStatementId);
    if (dataPermission == null) {
        return rules;
    }
    // 3. 已配置，但禁用
    if (!dataPermission.enable()) {
        return Collections.emptyList();
    }

    // 4. 已配置，只选择部分规则
    if (ArrayUtils.isNotEmpty(dataPermission.includeRules())) {
        return rules.stream().filter(rule -> ArrayUtils.contains(dataPermission.includeRules(), rule.getClass()))
                .collect(Collectors.toList()); // 一般规则不会太多，所以不采用 HashSet 查询
    }
    // 5. 已配置，只排除部分规则
    if (ArrayUtils.isNotEmpty(dataPermission.excludeRules())) {
        return rules.stream().filter(rule -> !ArrayUtils.contains(dataPermission.excludeRules(), rule.getClass()))
                .collect(Collectors.toList()); // 一般规则不会太多，所以不采用 HashSet 查询
    }
    // 6. 已配置，全部规则
    return rules;
}

}
`

[harawata]

When there is no setter for a property, it almost always means that the developer does not allow users to modify the value for a reason.

If a user modifies registered mappers after the initialization process, we cannot guarantee MyBatis works properly anymore, so we won't do it.
If we were to support what you want to achieve, it will be done by providing some kind of extension point rather than by adding a setter.