【Hbase】之 好友关系（20）

一、需求

需求:

例如：uid1 用户执行删除 uid2 这个好友，则 uid2 的好友列表中也必须删除 uid1

二、实现思路

# rowkey 为 用户Id
# friends 列族

rowkey      friends
uid1        uid2 uid3 uid4
uid2        uid1 uid3

1. 创建表 和 基本数据

# 版本为 1
$ create 'relations', {
   NAME => 'friends', VERSIONS => '1'}

# 插入记录 uid1 ：uid2 uid3 uid4
$ put 'relations', 'uid1', 'friends:uid2', 'uid2'
$ put 'relations', 'uid1', 'friends:uid3', 'uid3'
$ put 'relations', 'uid1', 'friends:uid4', 'uid4'

# 插入记录 uid2 ：uid1 uid3
$ put 'relations', 'uid2', 'friends:uid1', 'uid1'
$ put 'relations', 'uid2', 'friends:uid3', 'uid3'


hbase(main):015:0> scan 'relations'
ROW              COLUMN+CELL                                                                                                                             
 uid1            column=friends:uid2, timestamp=1598881670153, value=uid2
 uid1            column=friends:uid3, timestamp=1598881677381, value=uid3
 uid1            column=friends:uid4, timestamp=15988816835, value=uid4
 uid2            column=friends:uid1, timestamp=1598881698725, value=uid1
 uid2            column=friends:uid3, timestamp=1598881690459, value=uid3
 2 row(s) in 0.0520 seconds

2. 编写 Observer 协处理器

通过 Observer 协处理器捕捉到 relations 删除数据时, 对应的 rowkey也删除。

3. 上传 HDFS

$ scp -P 22 hadoop-practice-1.0-SNAPSHOT.jar root@172.16..121:/root

$ mv hadoop-practice-1.0-SNAPSHOT.jar processor4.jar

[root@linux121 ~]# hadoop fs -mkdir /processor
[root@linux121 ~]# hadoop fs -put processor4.jar /processor

4. 挂载协处理器

$ alter 'relations',METHOD =>'table_att','Coprocessor'=>'hdfs://linux121:9000/processor/processor5.jar|com.donaldy.hbase.homework.DeleteRelationsProcessor|1001|'

$ desc 'relations'

hbase(main):024:0> desc 'relations'
Table relations is ENABLED                                                                                                                                                             
relations, {
   TABLE_ATTRIBUTES => {
   coprocessor$1 => 'hdfs://linux121:9000/processor/processor5.jar|com.donaldy.hbase.homework.DeleteRelationsProcessor|1001|'}                           
COLUMN FAMILIES DESCRIPTION