Hive DDL 内部表外部表分区分桶行格式存储文件格式概述-白红宇

Hive DDL 内部表外部表分区分桶行格式存储文件格式概述

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发布时间：2019-06-27

本文共 26211 字，大约阅读时间需要 87 分钟。

创建数据库

CREATE DATABASE [IF NOT EXISTS] database_name  [COMMENT database_comment]  [LOCATION hdfs_path]

删除数据库

DROP DATABASE [IF EXISTS] database_name [RESTRICT|CASCADE];-- RESTRICT：默认选项只能删除空库-- CASCADE：可以删除库和库里的表

创建表

创建表CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name  [(col_name data_type [COMMENT col_comment], ...]  [COMMENT table_comment]  [PARTITIONED BY (col_name data_type [COMMENT col_comment], ...)]  [CLUSTERED BY (col_name, col_name, ...) [SORTED BY (col_name [ASC|DESC], ...)] INTO num_buckets BUCKETS]  [   [ROW FORMAT row_format]    [STORED AS file_format]  ]  [LOCATION hdfs_path]  [AS select_statement]; CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name  LIKE existing_table_or_view_name  [LOCATION hdfs_path];primitive_data_type  : TINYINT  | SMALLINT  | INT  | BIGINT  | BOOLEAN  | FLOAT  | DOUBLE  | DOUBLE PRECISION  | STRING  | BINARY  | TIMESTAMP  | DECIMAL  | DECIMAL(precision, scale)  | DATE  | VARCHAR  | CHAR row_format  : DELIMITED [FIELDS TERMINATED BY char [ESCAPED BY char]] [COLLECTION ITEMS TERMINATED BY char]        [MAP KEYS TERMINATED BY char] [LINES TERMINATED BY char]        [NULL DEFINED AS char]  | SERDE serde_name [WITH SERDEPROPERTIES (property_name=property_value, property_name=property_value, ...)] file_format:  : SEQUENCEFILE  | TEXTFILE    -- (Default, depending on hive.default.fileformat configuration)  | RCFILE  | ORC  | PARQUET  | AVRO  | JSONFILE  | INPUTFORMAT input_format_classname OUTPUTFORMAT output_format_classname

内部表，外部表

创建时指定external时为外部表，否则为内部表，或者通过desc formatted table_name;输出表的详细信息，其中Table Type:列会输出存储目录信息和数据表类型内部表（managed table），外部表（external table）

区别：

内部表数据由Hive自身管理，外部表数据由HDFS管理；

内部表数据存储的位置是hive.metastore.warehouse.dir（默认：/user/hive/warehouse），外部表数据的存储位置由自己制定；

删除内部表会直接删除元数据（metadata）及存储数据；删除外部表仅仅会删除元数据，HDFS上的文件并不会被删除；

对内部表的修改会将修改直接同步给元数据，而对外部表的表结构和分区进行修改，则需要修复（MSCK REPAIR TABLE table_name;）

外部表：hdfs上的共享数据，多个部门公用时采用

-- 创建内部表create table tb_managed(id      int,name    string,hobby   array
    
     ,add     map
     
      )row format delimitedfields terminated by ','collection items terminated by '-'map keys terminated by ':'lines terminated by '\n';-- 数据文件及内容complex_data_type.txt1,xiaoming,book-TV-code,beijing:chaoyang-shagnhai:pudong2,lilei,book-code,nanjing:jiangning-taiwan:taibei3,lihua,music-book,heilongjiang:haerbin-- load数据load data local inpath '/usr/local/hive-2.1.1/data_dir/complex_data_type.txt' overwrite into table tb_managed;-- 查询表模式信息0: jdbc:hive2://node225:10000/db01> desc formatted tb_managed;OK+-------------------------------+-------------------------------------------------------------+-----------------------+--+|           col_name            |                          data_type                          |        comment        |+-------------------------------+-------------------------------------------------------------+-----------------------+--+| # col_name                    | data_type                                                   | comment               ||                               | NULL                                                        | NULL                  || id                            | int                                                         |                       || name                          | string                                                      |                       || hobby                         | array
      
                                                      |                       || add                           | map
       
                                                  |                       ||                               | NULL                                                        | NULL                  || # Detailed Table Information  | NULL                                                        | NULL                  || Database:                     | db01                                                        | NULL                  || Owner:                        | root                                                        | NULL                  || CreateTime:                   | Wed Oct 10 15:21:31 CST 2018                                | NULL                  || LastAccessTime:               | UNKNOWN                                                     | NULL                  || Retention:                    | 0                                                           | NULL                  || Location:                     | hdfs://ns1/user/hive/warehouse/db01.db/tb_managed           | NULL                  || Table Type:                   | MANAGED_TABLE                                               | NULL                  || Table Parameters:             | NULL                                                        | NULL                  ||                               | numFiles                                                    | 1                     ||                               | numRows                                                     | 0                     ||                               | rawDataSize                                                 | 0                     ||                               | totalSize                                                   | 147                   ||                               | transient_lastDdlTime                                       | 1539156255            ||                               | NULL                                                        | NULL                  || # Storage Information         | NULL                                                        | NULL                  || SerDe Library:                | org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe          | NULL                  || InputFormat:                  | org.apache.hadoop.mapred.TextInputFormat                    | NULL                  || OutputFormat:                 | org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat  | NULL                  || Compressed:                   | No                                                          | NULL                  || Num Buckets:                  | -1                                                          | NULL                  || Bucket Columns:               | []                                                          | NULL                  || Sort Columns:                 | []                                                          | NULL                  || Storage Desc Params:          | NULL                                                        | NULL                  ||                               | colelction.delim                                            | -                     ||                               | field.delim                                                 | ,                     ||                               | mapkey.delim                                                | :                     ||                               | serialization.format                                        | ,                     |+-------------------------------+-------------------------------------------------------------+-----------------------+--+35 rows selected (0.346 seconds)-- 创建外部表create external table tb_external(id      int,name    string,hobby   array
        
         ,add     map
         
          )row format delimitedfields terminated by ','collection items terminated by '-'map keys terminated by ':'lines terminated by '\n'location '/tmp/hive/tb_external';-- load数据load data local inpath '/usr/local/hive-2.1.1/data_dir/complex_data_type.txt' overwrite into table tb_external;0: jdbc:hive2://node225:10000/db01> desc formatted tb_external;OK+-------------------------------+-------------------------------------------------------------+-----------------------+--+| col_name | data_type | comment |+-------------------------------+-------------------------------------------------------------+-----------------------+--+| # col_name | data_type | comment || | NULL | NULL || id | int | || name | string | || hobby | array
          
            | || add | map
           
             | || | NULL | NULL || # Detailed Table Information | NULL | NULL || Database: | db01 | NULL || Owner: | root | NULL || CreateTime: | Wed Oct 10 15:39:29 CST 2018 | NULL || LastAccessTime: | UNKNOWN | NULL || Retention: | 0 | NULL || Location: | hdfs://ns1/tmp/hive | NULL || Table Type: | MANAGED_TABLE | NULL || Table Parameters: | NULL | NULL || | numFiles | 1 || | totalSize | 147 || | transient_lastDdlTime | 1539157215 || | NULL | NULL || # Storage Information | NULL | NULL || SerDe Library: | org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe | NULL || InputFormat: | org.apache.hadoop.mapred.TextInputFormat | NULL || OutputFormat: | org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat | NULL || Compressed: | No | NULL || Num Buckets: | -1 | NULL || Bucket Columns: | [] | NULL || Sort Columns: | [] | NULL || Storage Desc Params: | NULL | NULL || | colelction.delim | - || | field.delim | , || | line.delim | \n || | mapkey.delim | : || | serialization.format | , |+-------------------------------+-------------------------------------------------------------+-----------------------+--+34 rows selected (0.22 seconds)

分区

是指按照数据的某列（值）或某些列（值）分为多个区，形式分区即数据表的子文件夹，查询时通过指定分区字段的值，直接从指定分区中查询避免执行权标扫描。

创建分区表的时候，通过关键字 partitioned by （partition_col data_type）声明该表是分区表，按partition_col进行分区，partition_col值一致的所有记录存放在一个分区中，可以依据多个列进行分区，即对某个分区的数据按照某些列继续分区。

向分区表导入数据的时候，要通过关键字partition（partition_col=value）显示声明数据要导入到表的哪个分区。

分区，是将满足某些条件的记录打包，做个记号，在查询时提高效率，在查询时分区字段会显示到客户端上，但并不真正在存储在数据表文件中，是所谓伪列。

分区表的分区会反映在文件系统中的存储路径，实际上是在表目录下创建了一个文件夹名为partition_col=value，并将该区导入的数据放置该在文件夹下面。

show partitions table_name;

静态分区

create table tb_partitions(id      int,name    string,hobby   array
    
     ,add     map
     
      )partitioned by (part_tag string)row format delimitedfields terminated by ','collection items terminated by '-'map keys terminated by ':'lines terminated by '\n';load data local inpath '/usr/local/hive-2.1.1/data_dir/complex_data_type.txt' into table tb_partitions partition(part_tag = 'first');load data local inpath '/usr/local/hive-2.1.1/data_dir/complex_data_type.txt' into table tb_partitions partition(part_tag = 'second');select * from tb_partitions where part_tag='first';insert overwrite table table_name partition(partition_col=value) select ...0: jdbc:hive2://node225:10000/db01> show partitions tb_partitions;OK+-----------------+--+|    partition    |+-----------------+--+| part_tag=first  |+-----------------+--+1 row selected (0.278 seconds)

动态分区

hive是批处理系统，为提高多分区插入数据的效率，hive提供了一个动态分区功能，其可以基于查询参数的位置去推断分区的名称，从而建立分区。

set hive.exec.dynamic.partition =true（默认false）,表示开启动态分区功能? ?

set hive.exec.dynamic.partition.mode = nonstrict(默认strict),表示允许所有分区都是动态的，否则必须有静态分区字段

系统默认以最后一个字段作为分区名，分区需要分区的字段只能放在后面，不能把顺序弄错。系统是根据查询字段的位置推断分区名的，而不是字段名称。

单字段分区

create table tb_part_dynamic_1(id      int,name    string,hobby   array
    
     ,add     map
     
      )partitioned by (tag string)row format delimitedfields terminated by ','collection items terminated by '-'map keys terminated by ':'lines terminated by '\n';insert overwrite table tb_part_dynamic_1 partition(tag) select id,name,hobby,add,part_tag from tb_partitions;

多字段同时静态和动态分区

create table tb_part_dynamic_2(id      int,name    string,hobby   array
    
     ,add     map
     
      )partitioned by (categ string,tag string)row format delimitedfields terminated by ','collection items terminated by '-'map keys terminated by ':'lines terminated by '\n';insert overwrite table tb_part_dynamic_2 partition(categ = 'big',tag) select id,name,hobby,add,part_tag from tb_partitions;

多字段全动态分区

create table tb_part_dynamic_3(id      int,name    string,hobby   array
    
     ,add     map
     
      )partitioned by (tag1 string,tag2 string)row format delimitedfields terminated by ','collection items terminated by '-'map keys terminated by ':'lines terminated by '\n';insert overwrite table tb_part_dynamic_3 partition(tag1,tag2) select id,name,hobby,add,categ,tag from tb_part_dynamic_2;

分桶

相对分区进行更细粒度的划分。分桶将整个数据内容安照某列属性值得hash值进行区分，如要安照clustered_col属性分为num_buckets个桶，就是对clustered_col属性值的hash值对num_buckets取摸，按照取模结果对数据分桶。如取模结果为0,1,2,..num_buckets-1的数据记录分别存放到数据表目录下的一个文件。

分桶之前要执行命令hive.enforce.bucketiong=true;

要使用关键字clustered by 指定分区依据的列名，还要指定分为多少桶num_buckets。

分桶的字段为数据表中已有的字段，所以不用指定数据类型。

查看分桶数据需要使用tablesample。

select * from table_name tablesample(bucket 1 out of 3 on id)

可以分桶又分区，但从文件目录信息看不到分桶的子文件信息，可以看到分区的目录信息

0: jdbc:hive2://node225:10000/db01> set hive.enforce.bucketing=true;No rows affected (0.008 seconds)0: jdbc:hive2://node225:10000/db01> set hive.enforce.bucketing;+------------------------------+--+|             set              |+------------------------------+--+| hive.enforce.bucketing=true  |+------------------------------+--+1 row selected (0.016 seconds)create table tb_clusters(id      int,name    string,hobby   array
    
     ,add     map
     
      )clustered by (id) sorted by (name asc) into 2 bucketsrow format delimitedfields terminated by ','collection items terminated by '-'map keys terminated by ':'lines terminated by '\n';insert overwrite table tb_clusters select id,name,hobby,add  from  tb_partitions;

The CLUSTERED BY and SORTED BY creation commands do not affect how data is inserted into a table – only how it is read.

row_format

默认记录和字段分隔符

\n 每行一条记录

^A 分隔列（八进制 \001）

^B 分隔ARRAY或者STRUCT中的元素，或者MAP中多个键值对之间分隔（八进制 \002）

^C 分隔MAP中键值对的“键”和“值”（八进制 \003）

只能使用单字符

此处通过测试有些问题，先记录测试情况

# 将正常的数据按所谓的默认分割符写入本地文件系统insert overwrite local directory '/usr/local/hive-2.1.1/data_dir/tb_insert_multi_02'row format delimitedfields terminated by '^A'collection items terminated by '^B'map keys terminated by '^C'lines terminated by '\n'stored as textfileselect * from  tb_insert_multi_02;# 本地文件情况[root@node225 ~]# cat /usr/local/hive-2.1.1/data_dir/tb_insert_multi_02/000000_01^xiaoming^book^TV^code^beijing^chaoyang^shagnhai^pudong^first^1002^lilei^book^code^nanjing^jiangning^taiwan^taibei^first^1003^lihua^music^book^heilongjiang^haerbin^first^1001^xiaoming^book^TV^code^beijing^chaoyang^shagnhai^pudong^first^1002^lilei^book^code^nanjing^jiangning^taiwan^taibei^first^1003^lihua^music^book^heilongjiang^haerbin^first^100# 按所谓默认分隔符创建表create table tb_data_format(id      int,name    string,hobby   array
    
     ,add     map
     
      ,tag1    string,tag2    int)row format delimitedfields terminated by '^A'collection items terminated by '^B'map keys terminated by '^C'lines terminated by '\n';0: jdbc:hive2://node225:10000/db01> desc formatted tb_data_format;OK+-------------------------------+-------------------------------------------------------------+-----------------------------+--+|           col_name            |                          data_type                          |           comment           |+-------------------------------+-------------------------------------------------------------+-----------------------------+--+| # col_name                    | data_type                                                   | comment                     ||                               | NULL                                                        | NULL                        || id                            | int                                                         |                             || name                          | string                                                      |                             || hobby                         | array
      
                                                      |                             || add                           | map
       
                                                  |                             || tag1                          | string                                                      |                             || tag2                          | int                                                         |                             ||                               | NULL                                                        | NULL                        || # Detailed Table Information  | NULL                                                        | NULL                        || Database:                     | db01                                                        | NULL                        || Owner:                        | root                                                        | NULL                        || CreateTime:                   | Thu Oct 11 16:42:25 CST 2018                                | NULL                        || LastAccessTime:               | UNKNOWN                                                     | NULL                        || Retention:                    | 0                                                           | NULL                        || Location:                     | hdfs://ns1/user/hive/warehouse/db01.db/tb_data_format       | NULL                        || Table Type:                   | MANAGED_TABLE                                               | NULL                        || Table Parameters:             | NULL                                                        | NULL                        ||                               | COLUMN_STATS_ACCURATE                                       | {\"BASIC_STATS\":\"true\"}  ||                               | numFiles                                                    | 0                           ||                               | numRows                                                     | 0                           ||                               | rawDataSize                                                 | 0                           ||                               | totalSize                                                   | 0                           ||                               | transient_lastDdlTime                                       | 1539247345                  ||                               | NULL                                                        | NULL                        || # Storage Information         | NULL                                                        | NULL                        || SerDe Library:                | org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe          | NULL                        || InputFormat:                  | org.apache.hadoop.mapred.TextInputFormat                    | NULL                        || OutputFormat:                 | org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat  | NULL                        || Compressed:                   | No                                                          | NULL                        || Num Buckets:                  | -1                                                          | NULL                        || Bucket Columns:               | []                                                          | NULL                        || Sort Columns:                 | []                                                          | NULL                        || Storage Desc Params:          | NULL                                                        | NULL                        ||                               | colelction.delim                                            | ^B                          ||                               | field.delim                                                 | ^A                          ||                               | line.delim                                                  | \n                          ||                               | mapkey.delim                                                | ^C                          ||                               | serialization.format                                        | ^A                          |+-------------------------------+-------------------------------------------------------------+-----------------------------+--+# load 数据load data local inpath '/usr/local/hive-2.1.1/data_dir/tb_insert_multi_02/000000_0' into table tb_data_format;# 查询确认表中数据，并未按期望的形式加载数据0: jdbc:hive2://node225:10000/db01> select * from tb_data_format;OK+--------------------+----------------------+-----------------------+---------------------+----------------------+----------------------+--+| tb_data_format.id  | tb_data_format.name  | tb_data_format.hobby  | tb_data_format.add  | tb_data_format.tag1  | tb_data_format.tag2  |+--------------------+----------------------+-----------------------+---------------------+----------------------+----------------------+--+| 1                  | xiaoming             | ["book"]              | {"TV":null}         | code                 | NULL                 || 2                  | lilei                | ["book"]              | {"code":null}       | nanjing              | NULL                 || 3                  | lihua                | ["music"]             | {"book":null}       | heilongjiang         | NULL                 || 1                  | xiaoming             | ["book"]              | {"TV":null}         | code                 | NULL                 || 2                  | lilei                | ["book"]              | {"code":null}       | nanjing              | NULL                 || 3                  | lihua                | ["music"]             | {"book":null}       | heilongjiang         | NULL                 |+--------------------+----------------------+-----------------------+---------------------+----------------------+----------------------+--+# 利用默认的分隔符创建数据表，查询表的结构信息，显示默认的分隔符并非所谓的“^A”等0: jdbc:hive2://node225:10000/db01> create table tb_data_delimit(. . . . . . . . . . . . . . . . . > id      int,. . . . . . . . . . . . . . . . . > name    string,. . . . . . . . . . . . . . . . . > hobby   array
        
         ,. . . . . . . . . . . . . . . . . > add     map
         
          ,. . . . . . . . . . . . . . . . . > tag1 string,. . . . . . . . . . . . . . . . . > tag2 int. . . . . . . . . . . . . . . . . > ). . . . . . . . . . . . . . . . . > ;OKNo rows affected (0.207 seconds)0: jdbc:hive2://node225:10000/db01> desc formatted tb_data_delimit;OK+-------------------------------+-------------------------------------------------------------+-----------------------------+--+| col_name | data_type | comment |+-------------------------------+-------------------------------------------------------------+-----------------------------+--+| # col_name | data_type | comment || | NULL | NULL || id | int | || name | string | || hobby | array
          
            | || add | map
           
             | || tag1 | string | || tag2 | int | || | NULL | NULL || # Detailed Table Information | NULL | NULL || Database: | db01 | NULL || Owner: | root | NULL || CreateTime: | Thu Oct 11 16:43:28 CST 2018 | NULL || LastAccessTime: | UNKNOWN | NULL || Retention: | 0 | NULL || Location: | hdfs://ns1/user/hive/warehouse/db01.db/tb_data_delimit | NULL || Table Type: | MANAGED_TABLE | NULL || Table Parameters: | NULL | NULL || | COLUMN_STATS_ACCURATE | {\"BASIC_STATS\":\"true\"} || | numFiles | 0 || | numRows | 0 || | rawDataSize | 0 || | totalSize | 0 || | transient_lastDdlTime | 1539247408 || | NULL | NULL || # Storage Information | NULL | NULL || SerDe Library: | org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe | NULL || InputFormat: | org.apache.hadoop.mapred.TextInputFormat | NULL || OutputFormat: | org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat | NULL || Compressed: | No | NULL || Num Buckets: | -1 | NULL || Bucket Columns: | [] | NULL || Sort Columns: | [] | NULL || Storage Desc Params: | NULL | NULL || | serialization.format | 1 |+-------------------------------+-------------------------------------------------------------+-----------------------------+--+# 同样将分隔符换成“\001”等也有问题0: jdbc:hive2://node225:10000/db01> create table tb_data_format(. . . . . . . . . . . . . . . . . > id int,. . . . . . . . . . . . . . . . . > name string,. . . . . . . . . . . . . . . . . > hobby array
            
             ,. . . . . . . . . . . . . . . . . > add map
             
              ,. . . . . . . . . . . . . . . . . > tag1 string,. . . . . . . . . . . . . . . . . > tag2 int. . . . . . . . . . . . . . . . . > ). . . . . . . . . . . . . . . . . > row format delimited. . . . . . . . . . . . . . . . . > fields terminated by '\001'. . . . . . . . . . . . . . . . . > collection items terminated by '\002'. . . . . . . . . . . . . . . . . > map keys terminated by '\003'. . . . . . . . . . . . . . . . . > lines terminated by '\n'. . . . . . . . . . . . . . . . . > ;

DELIMITED

每个字段之间

FIELDS TERMINATED BY char ','

集合内元素与元素之间，每组K-V对之间

COLLECTION ITEMS TERMINATED BY '-'

每组K-V对内部

MAP KEYS TERMINATED BY ':'

每条数据之间由换行符

LINES TERMINATED BY '\n'

SERDE

SerDe是Serialize/Deserilize的简称，目的是用于序列化和反序列化。

序列化是对象转换为字节序列的过程。

反序列化是字节序列恢复为对象的过程。

Serialize把hive使用的java object转换成能写入hdfs的字节序列，或者其他系统能识别的流文件。Deserilize把字符串或者二进制流转换成hive能识别的java object对象。比如：select语句会用到Serialize对象，把hdfs数据解析出来；insert语句会使用Deserilize，数据写入hdfs系统，需要把数据序列化。

hive创建表时，通过自定义的SerDe或使用Hive内置的SerDe类型指定数据的序列化和反序列化方式。

用row format 参数说明SerDe的类型

SerDe包括内置类型

Avro

ORC

RegEx

Thrift

Parquet

CSV

JsonSerDe

常用RegexSerde解析多字节分隔符

需要两个参数：

input.regex = "(.*)::(.*)::(.*)"

output.format.string = "%1$s %2$s %3$s"

create table t_user(userid      bigint  comment '用户id', gender      string  comment '性别', age         int     comment '年龄', occupation  string  comment '职业', zipcode     string  comment '邮政编码')comment '用户信息表'row format serde 'org.apache.hadoop.hive.serde2.RegexSerDe' with serdeproperties('input.regex'='(.*)::(.*)::(.*)::(.*)::(.*)','output.format.string'='%1$s %2$s %3$s %4$s %5$s')stored as textfile;

文件格式

TEXTFILE：为默认格式，导入数据时会直接把数据文件拷贝到hdfs上不进行处理，磁盘开销大，数据解析开销大。

SEQUENCEFILE，RCFILE，ORCFILE格式的表不能直接从本地文件导入数据，数据要先导入到textfile格式的表中，然后再从表中用insert导入SequenceFile,RCFile,ORCFile表中。

相比TEXTFILE和SEQUENCEFILE，RCFILE由于列式存储方式，数据加载时性能消耗较大，但是具有较好的压缩比和查询响应。数据仓库的特点是一次写入、多次读取，因此，整体来看，RCFILE相比其余两种格式具有较明显的优势。

SEQUENCEFILE

是Hadoop API提供的一种二进制文件支持，其具有使用方便、可分割、可压缩的特点。支持三种压缩选择：NONE，RECORD，BLOCK。Record压缩率低，一般建议使用BLOCK压缩。

RCFILE

是一种行列存储相结合的存储方式。首先，其将数据按行分块，保证同一个record在一个块上，避免读一个记录需要读取多个block。其次，块数据列式存储，有利于数据压缩和快速的列存取。

转载于:https://my.oschina.net/peakfang/blog/2240236

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