hive中导入json格式的数据（hive分区表）

hive中建立外部分区表，外部数据格式是json的如何导入呢？

json格式的数据表不必含有分区字段，只需要在hdfs目录结构中体现出分区就可以了

This is all according to this guide: http://blog.cloudera.com/blog/2012/12/how-to-use-a-serde-in-apache-hive/

 hive> ADD JAR /home/hadoop/hive-serdes-1.0-SNAPSHOT.jar;
 Added /home/hadoop/hive-serdes-1.0-SNAPSHOT.jar to class path
 Added resource: /home/hadoop/hive-serdes-1.0-SNAPSHOT.jar

In /tmp/new I have a file abc.json

The CREATE EXTERNAL TABLE command runs properly, but it doesn't take in any data:

 hive>
     > CREATE EXTERNAL TABLE tweets (
     >   id BIGINT,
     >   created_at STRING,
     >   source STRING,
     >   favorited BOOLEAN,
     >   retweeted_status STRUCT<
     >     text:STRING,
     >     user:STRUCT<screen_name:STRING,name:STRING>,
     >     retweet_count:INT>,
     >   entities STRUCT<
     >     urls:ARRAY<STRUCT<expanded_url:STRING>>,
     >     user_mentions:ARRAY<STRUCT<screen_name:STRING,name:STRING>>,
     >     hashtags:ARRAY<STRUCT<text:STRING>>>,
     >   text STRING,
     >   user STRUCT<
     >     screen_name:STRING,
     >     name:STRING,
     >     friends_count:INT,
     >     followers_count:INT,
     >     statuses_count:INT,
     >     verified:BOOLEAN,
     >     utc_offset:INT,
     >     time_zone:STRING>,
     >   in_reply_to_screen_name STRING
     > )
     > PARTITIONED BY (datehour INT)
     > ROW FORMAT SERDE 'com.cloudera.hive.serde.JSONSerDe'
     > LOCATION '/tmp/new';
 OK
 Time taken: 0.142 seconds

注意外部分区表需要手工添加分区

具体步骤

.) Run the create table statement.
.) In the directory /tmp/new/ create a sub directory datehour=<some int value>, and then put your .json file inside this.这里就是说只需要在hdfs上建立目录，目录体现分区信息，将数据放到对应目录，然后直接add partiton就好了
.) Run alter table statement adding this partition to metadata:
    alter table tweets add partition(datehour=<some int value>);
.) Now run the select statement.