[Java知识库]利用Mybatis拦截器实现数据权限

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利用Mybatis拦截器实现数据权限

在我们日常开发过程中，通常会涉及到数据权限问题，下面以我们常见的一种场景举例：

一个公司有很多部门，每个人所处的部门和角色也不同，所以数据权限也可能不同，比如超级管理员可以查看某张

表的素有信息，部门领导可以查看该部门下的相关信息，部门普通人员只可以查看个人相关信息，而且由于角色的

不同，各个角色所能查看到的数据库字段也可能不相同，那么此处就涉及到了数据权限相关的问题。那么我们该如

何处理数据权限相关的问题呢？我们提供一种通过Mybatis拦截器实现的方式，下面我们来具体实现一下

pom.xml依赖

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.13.RELEASE</version>
</parent>

<properties>
    <java.version>1.8</java.version>
    <mybatis-plus.version>3.2.0</mybatis-plus.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>${mybatis-plus.version}</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
</dependencies>

application.yml文件

server:
  port: 80

spring:
  application:
    name: data-scope
  datasource:
    url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=UTC
    username: root
    password: 123456
    druid:
      # 验证连接是否有效。此参数必须设置为非空字符串，下面三项设置成true才能生效
      validation-query: SELECT 1
      # 连接是否被空闲连接回收器(如果有)进行检验. 如果检测失败, 则连接将被从池中去除
      test-while-idle: true
      # 是否在从池中取出连接前进行检验, 如果检验失败, 则从池中去除连接并尝试取出另一个
      test-on-borrow: true
      # 是否在归还到池中前进行检验
      test-on-return: false
      # 连接在池中最小生存的时间，单位是毫秒
      min-evictable-idle-time-millis: 30000

#mybatis配置
mybatis-plus:
  type-aliases-package: com.mk.entity
  mapper-locations: classpath:mapper/**/*.xml
  global-config:
    db-config:
      id-type: auto
      field-strategy: not_empty
      logic-delete-value: 1
      logic-not-delete-value: 0
  configuration:
    map-underscore-to-camel-case: true
    cache-enabled: false
    call-setters-on-nulls: true
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

代码实现

DataScode.java

@Data
public class DataScope {

    // sql过滤条件
    String sqlCondition;

    // 需要过滤的结果字段
    String[] filterFields;

}

MybatisPlusConfig.java

@Configuration
public class MybatisPlusConfig {

    @Bean
    @ConditionalOnMissingBean
    public DataScopeInterceptor dataScopeInterceptor() {
        return new DataScopeInterceptor();
    }

    @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor page = new PaginationInterceptor();
        page.setDialectType(DbType.MYSQL.getDb());
        return page;
    }

    @Bean
    public ConfigurationCustomizer mybatisConfigurationCustomizer(){
        return new ConfigurationCustomizer() {
            @Override
            public void customize(MybatisConfiguration configuration) {
                configuration.setObjectWrapperFactory(new MybatisMapWrapperFactory());
            }
        };
    }
}

DataScopeInterceptor.java

@Slf4j
@Intercepts({@Signature(type = Executor.class, method = "query",
        args = {MappedStatement.class, Object.class, RowBounds.class,ResultHandler.class})})
public class DataScopeInterceptor implements Interceptor {

    @Override
    public Object intercept(Invocation invocation) throws Throwable {

        log.info("执行intercept方法：{}", invocation.toString());

        Object[] args = invocation.getArgs();
        MappedStatement ms = (MappedStatement) args[0];
        Object parameterObject = args[1];

        // 查找参数中包含DataScope类型的参数
        DataScope dataScope = findDataScopeObject(parameterObject);
        if (dataScope == null) {
            return invocation.proceed();
        }


        if (!ObjectUtils.isEmpty(dataScope.getSqlCondition())) {
            // id为执行的mapper方法的全路径名，如com.mapper.UserMapper
            String id = ms.getId();

            // sql语句类型 select、delete、insert、update
            String sqlCommandType = ms.getSqlCommandType().toString();

            // 仅拦截 select 查询
            if (!sqlCommandType.equals(SqlCommandType.SELECT.toString())) {
                return invocation.proceed();
            }

            BoundSql boundSql = ms.getBoundSql(parameterObject);
            String origSql = boundSql.getSql();
            log.info("原始SQL: {}", origSql);

            // 组装新的 sql
            String newSql = String.format("%s%s%s%s", "select * from (", origSql, ") ", dataScope.getSqlCondition());

            // 重新new一个查询语句对象
            BoundSql newBoundSql = new BoundSql(ms.getConfiguration(), newSql,
                    boundSql.getParameterMappings(), boundSql.getParameterObject());

            // 把新的查询放到statement里
            MappedStatement newMs = newMappedStatement(ms, new BoundSqlSqlSource(newBoundSql));
            for (ParameterMapping mapping : boundSql.getParameterMappings()) {
                String prop = mapping.getProperty();
                if (boundSql.hasAdditionalParameter(prop)) {
                    newBoundSql.setAdditionalParameter(prop, boundSql.getAdditionalParameter(prop));
                }
            }

            Object[] queryArgs = invocation.getArgs();
            queryArgs[0] = newMs;

            log.info("改写的SQL: {}", newSql);
        }

        Object result = invocation.proceed();

        return handleReslut(result, Arrays.asList(dataScope.getFilterFields()));
    }

    /**
     * 定义一个内部辅助类，作用是包装 SQL
     */
    class BoundSqlSqlSource implements SqlSource {
        private BoundSql boundSql;
        public BoundSqlSqlSource(BoundSql boundSql) {
            this.boundSql = boundSql;
        }
        public BoundSql getBoundSql(Object parameterObject) {
            return boundSql;
        }

    }

    private MappedStatement newMappedStatement (MappedStatement ms, SqlSource newSqlSource) {
        MappedStatement.Builder builder = new
                MappedStatement.Builder(ms.getConfiguration(), ms.getId(), newSqlSource, ms.getSqlCommandType());
        builder.resource(ms.getResource());
        builder.fetchSize(ms.getFetchSize());
        builder.statementType(ms.getStatementType());
        builder.keyGenerator(ms.getKeyGenerator());
        if (ms.getKeyProperties() != null && ms.getKeyProperties().length > 0) {
            builder.keyProperty(ms.getKeyProperties()[0]);
        }
        builder.timeout(ms.getTimeout());
        builder.parameterMap(ms.getParameterMap());
        builder.resultMaps(ms.getResultMaps());
        builder.resultSetType(ms.getResultSetType());
        builder.cache(ms.getCache());
        builder.flushCacheRequired(ms.isFlushCacheRequired());
        builder.useCache(ms.isUseCache());
        return builder.build();
    }

    @Override
    public Object plugin(Object target) {
        log.info("plugin方法：{}", target);

        if (target instanceof Executor) {
            return Plugin.wrap(target, this);
        }
        return target;

    }

    @Override
    public void setProperties(Properties properties) {
        // 获取属性
        // String value1 = properties.getProperty("prop1");
        log.info("properties方法：{}", properties.toString());
    }



    /**
     * 查找参数是否包括DataScope对象
     *
     * @param parameterObj 参数列表
     * @return DataScope
     */
    private DataScope findDataScopeObject(Object parameterObj) {
        if (parameterObj instanceof DataScope) {
            return (DataScope) parameterObj;
        } else if (parameterObj instanceof Map) {
            for (Object val : ((Map<?, ?>) parameterObj).values()) {
                if (val instanceof DataScope) {
                    return (DataScope) val;
                }
            }
        }
        return null;
    }


    public Object handleReslut(Object returnValue, List<String> filterFields){
        if(returnValue != null && !ObjectUtils.isEmpty(filterFields)){
            if (returnValue instanceof ArrayList<?>){
                List<?> list = (ArrayList<?>) returnValue;
                List<Object> newList  = new ArrayList<Object>();
                if (1 <= list.size()) {
                    for(Object object:list){
                        if (object instanceof Map) {
                            Map map = (Map) object;
                            for (String key : filterFields) {
                                map.remove(key);
                            }
                            newList.add(map);
                        } else {
                            newList.add(decrypt(filterFields, object));
                        }
                    }
                    returnValue = newList;
                }
            } else {
                if (returnValue instanceof Map) {
                    Map map = (Map) returnValue;
                    for (String key : filterFields) {
                        map.remove(key);
                    }
                } else {
                    returnValue = decrypt(filterFields, returnValue);
                }
            }
        }
        return returnValue;
    }


    public static <T> T decrypt(List<String> filterFields, T t) {
        Field[] declaredFields = t.getClass().getDeclaredFields();
        try {
            if (declaredFields != null && declaredFields.length > 0) {
                for (Field field : declaredFields) {
                    if (filterFields.contains(field.getName())) {
                        field.setAccessible(true);
                        field.set(t, null);
                        field.setAccessible(false);
                    }
                }
            }
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }

        return t;
    }
}

SalariesMapper.xml

<mapper namespace="com.mk.mapper.SalariesMapper">
    <select id="pageList" resultType="com.mk.entity.Salaries">
        SELECT * from salaries where salary between #{start} and #{end}
    </select>

    <select id="getByEmpNo" resultType="java.util.Map">
        select * from salaries where emp_no = #{empNo} limit 0,1
    </select>
</mapper>

SalariesMapper.java

@Mapper
public interface SalariesMapper extends BaseMapper<Salaries> {

    List<Salaries> pageList(DataScope dataScope, @Param("start") int start,  @Param("end") int end, Page<Salaries> page);

    Map<String, Object> getByEmpNo(DataScope dataScope, @Param("empNo") int empNo);
}

SalariesService.java

@Service
public class SalariesService extends ServiceImpl<SalariesMapper, Salaries> {

    @Autowired
    private SalariesMapper salariesMapper;

    public List<Salaries> getList(){
        Page<Salaries> page = new Page<>(1, 10);
        DataScope dataScope = new DataScope();
        // 设置查询条件
        dataScope.setSqlCondition("s where 1=1 and s.emp_no = '10001'");
        // 将结果集过滤掉salary和toDate字段
        dataScope.setFilterFields(new String[]{"salary", "toDate"});
        return salariesMapper.pageList(dataScope, 60000, 70000, page);

    }

    public Map<String, Object> getByEmpNo() {
        DataScope dataScope = new DataScope();
        // 将结果集过滤掉salary和toDate字段
        dataScope.setFilterFields(new String[]{"salary", "toDate"});
        return salariesMapper.getByEmpNo(dataScope, 10001);
    }
}

启动服务，执行相关操作，sql在执行之前会执行DataScopeInterceptor拦截器中的逻辑，从而改变sql，具体的

相关操作就是将原来的sql语句origSql在外层包装一层过滤条件，如：select * from (origSql)?过滤条件，

此处的过滤条件要封装到DataScope对象中，例如：dataScope.setSqlCondition("s where 1=1 and

s.emp_no = '10001'")?， 那么在经过拦截器处理以后要执行的sql语句为

select * from (origSql) s where 1=1 and s.emp_no = '10001', 从而实现数据权限相操作，当然此处的过滤条件只是为了演示效果举的一个例子

而已，在实际开发过程中要根据用户角色等等设置具体的过滤条件。