MyBatis的mapper.xml文件热加载功能实现方案

<!-- 在 mybatis-config.xml 中启用自动重载 -->
<configuration>
    <settings>
        <!-- 开发环境启用，生产环境慎用 -->
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>
</settings>

@Intercepts({
    @Signature(type = Executor.class, method = "query", 
               args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
})
public class MybatisHotReloadPlugin implements Interceptor {
    // 监控文件变化并重新加载
}

# 1. 查找类加载器
sc -d com.example.mapper.*Mapper

# 2. 修改对应的Mapper接口类（需要重新编译）
jad --source-only com.example.mapper.UserMapper > /tmp/UserMapper.java
# 修改后重新编译
mc -c <classloaderHash> /tmp/UserMapper.java -d /tmp

# 3. 重新加载类
redefine -c <classloaderHash> /tmp/UserMapper.class

public class MybatisHotReloadUtil {
    public static void reloadMapper(SqlSessionFactory sqlSessionFactory, 
                                   String mapperLocation) throws Exception {
        Configuration configuration = sqlSessionFactory.getConfiguration();
        
        // 1. 清除原有缓存
        configuration.getMappedStatements().forEach(ms -> {
            if (ms.getId().contains(mapperLocation)) {
                // 清除相关缓存
            }
        });
        
        // 2. 重新解析XML
        XMLMapperBuilder xmlMapperBuilder = new XMLMapperBuilder(
            new FileInputStream(mapperLocation),
            configuration,
            mapperLocation,
            configuration.getSqlFragments()
        );
        xmlMapperBuilder.parse();
    }
}

# 调用热加载方法
ognl '@com.example.MybatisHotReloadUtil@reloadMapper(
      @org.apache.ibatis.session.SqlSessionFactory@getObject(), 
      "mapper/UserMapper.xml")'

# 开发环境配置热加载
mybatis.configuration.local-cache-scope=statement
mybatis.mapper-locations-refresh-interval=5s

# 生产环境关闭所有热加载功能
# 通过CI/CD流程进行版本更新