hadoop - HIVE - 逃避双引号问题

Question

我正在尝试将带有管道分隔符的 csv 加载到配置单元外部表中。数据字段中出现的管道用引号括起来。数据中出现的双引号用\转义。当我配置外部表时，我看到带有双引号的数据没有被正确解释。

test.csv

id|name
105|"Test | pipe delim in field"
107|\" Test Escaped single double quote in HIVE
108|\" Test Escaped enclosed double quote in HIVE \"
109|\\" Test Escaped enclosed double quote in HIVE \"
110|\\" Test Escaped enclosed double quote in HIVE \\"

External table create statement

drop table test_schema.hive_test;
CREATE EXTERNAL TABLE test_schema.hive_test (id string, name string) 
ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.OpenCSVSerde' WITH SERDEPROPERTIES
(
"separatorChar" = "|",
"quoteChar" = "\"",
"escapeChar" = "\\"
)
LOCATION '/staging/test/hive'
tblproperties ("skip.header.line.count"="1");

Output

+---------------+-------------------------------------------------+
| hive_test.id  |                 hive_test.name                  |
+---------------+-------------------------------------------------+
| 105           | Test | pipe delim in field                      |
| 107           | NULL                                            |
| 108           | NULL                                            |
| 109           | NULL                                            |
| 110           | " Test Escaped enclosed double quote in HIVE \  |
+---------------+-------------------------------------------------+

Expected Output

+---------------+-------------------------------------------------+
| hive_test.id  |       hive_test.name                            |
+---------------+-------------------------------------------------+
| 105           | Test | pipe delim in field                      |
| 107           | " Test Escaped single double quote in HIVE      |
| 108           | " Test Escaped enclosed double quote in HIVE "  |
| 109           | NULL                                            |
| 110           | NULL                                            |
+---------------+-------------------------------------------------+

打开 CSV 版本 2.3

Answer 1

遗憾的是，这是不可能实现的，因为 OpenCSV 使用单个字符作为转义符，而实际上您正在尝试使用双反斜杠作为转义符(这将是 string )。在 OpenCSVSerde 类中，您可以发现无论您作为转义字符传递什么，OpenCSVSerde获取字符串值的第一个字符 https://github.com/apache/hive/blob/master/serde/src/java/org/apache/hadoop/hive/serde2/OpenCSVSerde.java#L98
这是当前代码作为引用

  private char getProperty(final Properties tbl, final String property, final char def) {
final String val = tbl.getProperty(property);

if (val != null) {
  return val.charAt(0);
}

return def;

}
我认为缺少一个警告，让用户在创建表时知道只支持单个字符。