数据权限dataScope的一种实现方式：mybatis拦截器改写SQL（springboot）

假设原始SQL如下：

SELECt  id,ip,port,host_addr,slave_addr,type,value,unit,create_time,update_time,del_flag,device_id,merchant_id,tenant_id  FROM xxx_value 
WHERe (del_flag = ?)

下面是改写的拦截器代码：

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.apache.ibatis.executor.statement.StatementHandler;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.reflection.DefaultReflectorFactory;
import org.apache.ibatis.reflection.metaObject;
import org.apache.ibatis.reflection.SystemmetaObject;
import org.springframework.stereotype.Component;

import java.lang.reflect.Field;
import java.sql.Connection;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;


@Intercepts({
     @Signature(
             type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class}
     )
})
@Slf4j
@Component
public class MyOwnBatisInterceptor implements Interceptor {

    @Override
    public Object intercept(Invocation invocation) throws Throwable {
            StatementHandler statementHandler = (StatementHandler) invocation.getTarget();
            metaObject metaObject = metaObject.forObject(statementHandler,
                    SystemmetaObject.DEFAULT_OBJECT_FACTORY,
                    SystemmetaObject.DEFAULT_OBJECT_WRAPPER_FACTORY,
                    new DefaultReflectorFactory());

            //先拦截到RoutingStatementHandler，里面有个StatementHandler类型的delegate变量，其实现类是baseStatementHandler，然后就到baseStatementHandler的成员变量mappedStatement
            MappedStatement mappedStatement = (MappedStatement) metaObject.getValue("delegate.mappedStatement");

            //sql语句类型 select、delete、insert、update
            String sqlCommandType = mappedStatement.getSqlCommandType().toString();
            if (!"SELECT".equals(sqlCommandType)){
                //只是拦截：SELECT
                return invocation.proceed();
            }

            //id为执行的mapper方法的全路径名，如com.uv.dao.UserMapper.insertUser
            String id = mappedStatement.getId();
            log.info("拦截到当前请求方法的全路径名为--->:  " + id);

            //获取到原始sql语句
            BoundSql boundSql = statementHandler.getBoundSql();
            String sql = boundSql.getSql();

            //获取参数
            Object parameter = statementHandler.getParameterHandler().getParameterObject();
            log.info("拦截到当前请求SQL为--->: "  + sql);
            log.info("拦截到当前请求类型为--->: "  + sqlCommandType);
            log.info("拦截到当前请求参数为--->: "  + parameter);

            //模拟dataScope的数据权限ids
            List ids = new ArrayList();
            ids.add(1442769582176501761L);
            //where条件
            String whereSql = " where scope.%s in (%s) ";
            //数据过滤
            sql  = String.format(" select %s from (%s) scope " + whereSql, new Object[]{"*", sql, "id", StringUtils.join(ids,",")});
            log.info("拦截到当前请求SQL改写之后为--->: "  + sql);
            //反射改写新的SQL
            Field field = boundSql.getClass().getDeclaredField("sql");
            field.setAccessible(true);
            field.set(boundSql, sql);

        // 执行完上面的任务后，不改变原有的sql执行过程
        return invocation.proceed();
    }

    @Override
    public Object plugin(Object target) {
        return Plugin.wrap(target, this);
    }

    @Override
    public void setProperties(Properties properties) {}
}

改写之后SQL：

select * from (SELECt  id,ip,port,host_addr,slave_addr,type,value,unit,create_time,update_time,del_flag,device_id,merchant_id,tenant_id  FROM xxx_value 
WHERe (del_flag = ?)) scope  where scope.id in (1442769582176501761)