hive 解析 json 字符串

json_tuple (推荐用这个)

1. json_tuple udtf 功能是在 hive 0.7 版本之后加入的，具体使用方法：

select a.timestamp, b.*
from log a lateral view json_tuple(a.appevent, 'eventid', 'eventname') b as f1, f2;

get_json_object

1. 基本使用方法

select get_json_object(src_json.json,'[key]') from src_json;

2. 可以使用某些JSONPath

• $ : Root object
• . : Child operator
• [] : Subscript operator for array
• • : Wildcard for []

+----+
                               json
+----+
{"store":
  {"fruit":\[{"weight":8,"type":"apple"},{"weight":9,"type":"pear"}],
   "bicycle":{"price":19.95,"color":"red"}
  },
 "email":"amy@only_for_json_udf_test.net",
 "owner":"amy"
}
+----+

hive> SELECT get_json_object(src_json.json, '$.owner') FROM src_json;
amy
 
hive> SELECT get_json_object(src_json.json, '$.store.fruit\[0]') FROM src_json;
{"weight":8,"type":"apple"}
 
hive> SELECT get_json_object(src_json.json, '$.non_exist_key') FROM src_json;
NULL

参考文献： https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF#LanguageManualUDF-get_json_object