mybatis-plus数据权限实现代码

// @DataScope
@Documented
@Inherited
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
public @interface DataScope {
    DataColumn[] value() default {};
}

//@DataColumn
@Documented
@Inherited
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD, ElementType.TYPE})
@Repeatable(DataScope.class)
public @interface DataColumn {
    String alias() default "";
    String name();
    ColumnType type() default ColumnType.USER;
}

public enum ColumnType {
    USER(UserDataColumnStrategy.class),
    DEPT(DeptDataColumnStrategy.class);
    private Class<? extends AbstractDataColumnStrategy> clazz;
    ColumnType(Class<? extends AbstractDataColumnStrategy> userDataColumnStrategyClass) {
    }
    public Class<? extends AbstractDataColumnStrategy> getClazz() {
        return clazz;
    }
}

public class DataPermissionInterceptor extends JsqlParserSupport implements InnerInterceptor {
    private static final String COUNT_PRE = "_COUNT";
    private MappedStatement ms;
    private DataScope dataScope;
	//重写查询之前方法
    @Override
    public void beforeQuery(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) throws SQLException {
        this.ms = ms;
        if (InterceptorIgnoreHelper.willIgnoreDataPermission(ms.getId())) {
            PluginUtils.MPBoundSql mpBs = PluginUtils.mpBoundSql(boundSql);
            mpBs.sql(this.parserSingle(mpBs.sql(), ms.getId()));
            return;
        }
        //获取权限注解 如果没有加注解 则忽略数据权限
        DataScope dataScope = this.getPermissionAnnotation(ms);
        if (dataScope == null) {
            return;
        }
        this.dataScope = dataScope;
        PluginUtils.MPBoundSql mpBs = PluginUtils.mpBoundSql(boundSql);
        mpBs.sql(this.parserSingle(mpBs.sql(), ms.getId()));
    }
		//重写处理Select方法
    @Override
    protected void processSelect(Select select, int index, String sql, Object obj) {
        SelectBody selectBody = select.getSelectBody();
        //如果是_COUNT结尾的SQL 则是PageHelper的统计SQL 包裹了原SQL 则需要获取到子句 进行条件添加
        try {
            if (obj.toString().endsWith(COUNT_PRE)) {
                PlainSelect plainSelect = (PlainSelect) selectBody;
                FromItem fromItem = plainSelect.getFromItem();
                if (fromItem instanceof SubSelect) {
                    SubSelect subSelect = (SubSelect) fromItem;
                    SelectBody selectBody1 = subSelect.getSelectBody();
                    this.setWhere((PlainSelect) selectBody1, (String) obj);
                }
            } else {
                this.setWhere((PlainSelect) selectBody, (String) obj);
            }
        } catch (IllegalAccessException | InstantiationException e) {
            e.printStackTrace();
            logger.error("处理数据权限SQL异常 error:{}", e);
            throw new RuntimeException(e.getMessage());
        }
    }
		//设置条件的方法
    private void setWhere(PlainSelect plainSelect, String whereSegment) throws IllegalAccessException, InstantiationException {
        DataColumn[] columns = this.getDataScope().value();
        //如果没有添加数据权限列 返回
        if (columns.length < 1) {
            return;
        }
        //获取所有需要处理的数据权限列，根据枚举获取SQL处理的策略
        for (DataColumn column : columns) {
            Class<? extends AbstractDataColumnStrategy> clazz = column.type().getClazz();
            AbstractDataColumnStrategy strategy = clazz.newInstance();
            strategy.setAlias(column.alias());
            strategy.setName(column.name());
            strategy.setPlainSelect(plainSelect);
            PlainSelect strategyPlainSelect = strategy.getPlainSelect();
            plainSelect = strategyPlainSelect;
        }
    }
    /**
     * 获得权限注释
     *
     * @param ms
     * @return {@link DataScope}
     */
    private DataScope getPermissionAnnotation(MappedStatement ms) {
        DataScope data = null;
        try {
            // id为执行的mapper方法的全路径名，如com.mapper.UserMapper
            String id = ms.getId();
            log.info("解析得到全类型名称 ID:{}", id);
            //统计SQL取得注解也是实际查询id上得注解，所以需要去掉_COUNT
            if (id.contains(COUNT_PRE)) {
                id = id.replace(COUNT_PRE, "");
            }
            //获取类名和方法名
            String className = id.substring(0, id.lastIndexOf("."));
            String methodName = id.substring(id.lastIndexOf(".") + 1);
            final Class<?> cls = Class.forName(className);
            final Method[] method = cls.getMethods();
            //反射 获取注解
            for (Method me : method) {
                if (me.getName().equals(methodName) && me.isAnnotationPresent(DataScope.class)) {
                    data = me.getAnnotation(DataScope.class);
                }
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return data;
     }
   }

@Data
public class DataPermissionDto {
    private List<Long> userIds;
    private List<Long> deptIds;
    private Long myUserId;
    private Long myDeptId;
    private Long tenantId;
}
//线程池
public class DataPermissionTenantHolder {
    /**
     * 支持父子线程之间的数据传递
     */
    private static final ThreadLocal<DataPermissionDto> CONTEXT_HOLDER = new TransmittableThreadLocal<>();
    public static <T extends DataPermissionDto> void setTenant(T tenant) {
        CONTEXT_HOLDER.set(tenant);
    }
    public static <T extends DataPermissionDto> T getTenant() {
        return (T) CONTEXT_HOLDER.get();
    }
    public static void clear() {
        CONTEXT_HOLDER.remove();
    }
}
```java
public class UserDataColumnStrategy extends AbstractDataColumnStrategy {
    @Override
    public PlainSelect handleColumn() {
        String alias = getAlias();
        String name = getName();
        String column = name;
        if (StringUtils.isNotBlank(alias)) {
            column = alias.trim() + "." + name.trim();
        }
        PlainSelect plainSelect = getPlainSelect();
        DataPermissionDto tenant = DataPermissionTenantHolder.getTenant();
        List<Long> userIds = tenant.getUserIds();
        //如果线程中没有 数据权限中的用户集合
        if (CollectionUtils.isEmpty(userIds)) {
            Long myUserId = tenant.getMyUserId();
            EqualsTo equalsTo = new EqualsTo();
            equalsTo.setLeftExpression(new Column(column));
            equalsTo.setRightExpression(new LongValue(myUserId));
            if (null == plainSelect.getWhere()) {
                // 不存在 where 条件
                plainSelect.setWhere(new Parenthesis(equalsTo));
            } else {
                // 存在 where 条件 and 处理
                plainSelect.setWhere(new AndExpression(plainSelect.getWhere(), equalsTo));
            }
            return plainSelect;
        }
        // 有数据权限中的用户集合
        ItemsList itemsList = new ExpressionList(userIds.stream().map(LongValue::new).collect(Collectors.toList()));
        InExpression inExpression = new InExpression(new Column(column), itemsList);
        if (null == plainSelect.getWhere()) {
            // 不存在 where 条件
            plainSelect.setWhere(new Parenthesis(inExpression));
        } else {
            // 存在 where 条件 and 处理
            plainSelect.setWhere(new AndExpression(plainSelect.getWhere(), inExpression));
        }
        return plainSelect;
    }
}

 @Bean
    @ConditionalOnMissingBean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        //是否开启多租户（这里是多租户插件部分,下次再提）
        if (tenantProperties.isEnabled()) {
            TenantLineInnerInterceptor tenantLineInnerInterceptor = new TenantLineInnerInterceptor(new TenantLineHandlerInterceptor(tenantProperties));
            interceptor.addInnerInterceptor(tenantLineInnerInterceptor);
        }
		//数据权限的插件
        interceptor.addInnerInterceptor(new DataPermissionInterceptor());
        return interceptor;
    }