hive表字段里有换行符，导致一行变多行或者字段错乱

- 日理万妓 2022-12-10 07:24 3阅读 0赞

### 文章目录 ###

*  1，问题
 *  2，产生原因
 *  3，解决办法

# 1，问题 #

*  制作测试数据：hue里面添加hbase表数据，在编辑器里面换行保存即可
 *  问题分析-- 字段内容有换行符，导致内容多一行：[ https://issues.apache.org/jira/browse/HIVE-1898 ][https_issues.apache.org_jira_browse_HIVE-1898]  
    ( LazySimpleSerDe.SerDeParameters --> which eliminates the newline chars during deserialization )

#################### hbase数据：字段有换行符号
    hbase(main):001:0> get 'test','r2'
    COLUMN                                   CELL
     f:age                                   timestamp=1599799051999, value=23
     f:name                                  timestamp=1600840740995, value=test2\x0Atest1\x0Aa\x0Aa\x0Aa\x0Aa
    2 row(s) in 0.1930 seconds
    
    hbase(main):003:0> get 'test','r4'
    COLUMN                                   CELL
     f:id                                    timestamp=1600842800999, value=2
     f:name                                  timestamp=1600842800999, value=tom1\x0Dtom2\x0Dtom3
    2 row(s) in 0.0050 seconds
    
    
    #################### hbase数据外表：hive查询换行
    hive> show create table test_hbase_ext;
    CREATE EXTERNAL TABLE `test_hbase_ext`(
      `rowkey` string COMMENT 'from deserializer',
      `name` string COMMENT 'from deserializer',
      `age` string COMMENT 'from deserializer')
    ROW FORMAT SERDE
      'org.apache.hadoop.hive.hbase.HBaseSerDe'
    STORED BY
      'org.apache.hadoop.hive.hbase.HBaseStorageHandler'
    WITH SERDEPROPERTIES (
      'hbase.columns.mapping'=':key,f:name,f:age',
      'serialization.format'='1')
    TBLPROPERTIES (
      'hbase.table.name'='test',
      'transient_lastDdlTime'='1600840936')
    Time taken: 0.095 seconds, Fetched: 14 row(s)
    
    
    hive> select * from test_hbase_ext where rowkey ='r2';
    Stage-Stage-1: Map: 1   Cumulative CPU: 5.51 sec   HDFS Read: 11818 HDFS Write: 26 SUCCESS
    Total MapReduce CPU Time Spent: 5 seconds 510 msec
    OK
    test_hbase_ext.rowkey   test_hbase_ext.name     test_hbase_ext.age
    r2      test2   NULL
    test1   NULL    NULL
    a       NULL    NULL
    a       NULL    NULL
    a       NULL    NULL
    a       23      NULL
    Time taken: 22.267 seconds, Fetched: 6 row(s)
    
    hive> select * from test_hbase_ext where rowkey ='r4';
    Stage-Stage-1: Map: 1   Cumulative CPU: 5.37 sec   HDFS Read: 4368 HDFS Write: 21 SUCCESS
    Total MapReduce CPU Time Spent: 5 seconds 370 msec
    OK
    test_hbase_ext.rowkey   test_hbase_ext.name     test_hbase_ext.age
    r4      tom1    NULL
    tom2    NULL    NULL
    tom3    NULL    NULL
    Time taken: 16.522 seconds, Fetched: 3 row(s)
    hive>

# 2，产生原因 #

#-- 问题原因： (hbaes:\x0A|D --> hive: data1换行data2换行data3--> 多一行 )
    #-- 考虑： hive读取数据时，把数据里的换行转换为MYEOF这种自定义的换行符号
    \x0A: 10  ASCII是\n
    \x0D: 13  ASCII是\r

# 3，解决办法 #

hive(data1MYEOFdata2MYEOFdata3) --> java中间处理环节：string.replaceAll(MYEOF,"\\n") —> 数据显示正常

hive> SELECT rowkey,regexp_replace(name,'\r|\n|\r\n','MYEOF') from test_hbase_ext2;
    Stage-Stage-1: Map: 1   Cumulative CPU: 5.46 sec   HDFS Read: 4206 HDFS Write: 139 SUCCESS
    rowkey  _c1
    r1      test
    r2      test2MYEOFtest1MYEOFaMYEOFaMYEOFaMYEOFa
    r3      tom1MYEOFtom2MYEOFtom3
    r4      tom1MYEOFtom2MYEOFtom3
    Time taken: 15.117 seconds, Fetched: 4 row(s)

[https_issues.apache.org_jira_browse_HIVE-1898]: https://issues.apache.org/jira/browse/HIVE-1898