HBASE-14638 Move Jython info from the Wiki to the Ref Guide

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Misty Stanley-Jones 2015-10-19 12:03:25 +10:00
parent 12a718d0ca
commit 9659f14020
1 changed files with 111 additions and 9 deletions

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@ -27,14 +27,10 @@
:icons: font
:experimental:
This chapter will cover access to Apache HBase either through non-Java languages, or through custom protocols.
For information on using the native HBase APIs, refer to link:http://hbase.apache.org/apidocs/index.html[User API Reference] and the new <<hbase_apis,HBase APIs>> chapter.
[[nonjava.jvm]]
== Non-Java Languages Talking to the JVM
Currently the documentation on this topic is in the link:http://wiki.apache.org/hadoop/Hbase[Apache HBase Wiki].
See also the link:http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/thrift/package-summary.html#package_description[Thrift API Javadoc].
This chapter will cover access to Apache HBase either through non-Java languages and
through custom protocols. For information on using the native HBase APIs, refer to
link:http://hbase.apache.org/apidocs/index.html[User API Reference] and the
<<hbase_apis,HBase APIs>> chapter.
== REST
@ -640,6 +636,17 @@ To use Scala with HBase, your CLASSPATH must include HBase's classpath as well a
the Scala JARs required by your code. First, use the following command on a server
running the HBase RegionServer process, to get HBase's classpath.
[[jython]]
== Jython
=== Setting the Classpath
To use Jython with HBase, your CLASSPATH must include HBase's classpath as well as
`jython.jar`. First, use the following command on a server running the HBase RegionServer
process, to get HBase's classpath.
>>>>>>> HBASE-14638 Move Jython info from the Wiki to the Ref Guide
[source, bash]
----
$ ps aux |grep regionserver| awk -F 'java.library.path=' {'print $2'} | awk {'print $1'}
@ -648,6 +655,7 @@ $ ps aux |grep regionserver| awk -F 'java.library.path=' {'print $2'} | awk {'pr
----
Set the `$CLASSPATH` environment variable to include the path you found in the previous
<<<<<<< 12a718d0ca507c911f589d2926cfc408e4155b0e
step, plus the path of `scala-library.jar` and each additional Scala-related JAR needed for
your project.
@ -703,4 +711,98 @@ val theget= new Get(Bytes.toBytes("rowkey1"))
val result=table.get(theget)
val value=result.value()
println(Bytes.toString(value))
----
----
=======
step, plus the path to `jython.jar`.
[source, bash]
----
$ export CLASSPATH=$CLASSPATH:/usr/lib/hadoop/lib/native:/usr/lib/hbase/lib/native/Linux-amd64-64:/path/to/jython.jar
----
Start a Jython shell with HBase and Hadoop JARs in the classpath:
$ bin/hbase org.python.util.jython
=== Jython Code Examples
.Table Creation, Population, Get, and Delete with Jython
====
The following Jython code example creates a table, populates it with data, fetches
the data, and deletes the table.
[source,jython]
----
import java.lang
from org.apache.hadoop.hbase import HBaseConfiguration, HTableDescriptor, HColumnDescriptor, HConstants
from org.apache.hadoop.hbase.client import HBaseAdmin, HTable, Get
from org.apache.hadoop.hbase.io import Cell, RowResult
# First get a conf object. This will read in the configuration
# that is out in your hbase-*.xml files such as location of the
# hbase master node.
conf = HBaseConfiguration()
# Create a table named 'test' that has two column families,
# one named 'content, and the other 'anchor'. The colons
# are required for column family names.
tablename = "test"
desc = HTableDescriptor(tablename)
desc.addFamily(HColumnDescriptor("content:"))
desc.addFamily(HColumnDescriptor("anchor:"))
admin = HBaseAdmin(conf)
# Drop and recreate if it exists
if admin.tableExists(tablename):
admin.disableTable(tablename)
admin.deleteTable(tablename)
admin.createTable(desc)
tables = admin.listTables()
table = HTable(conf, tablename)
# Add content to 'column:' on a row named 'row_x'
row = 'row_x'
update = Get(row)
update.put('content:', 'some content')
table.commit(update)
# Now fetch the content just added, returns a byte[]
data_row = table.get(row, "content:")
data = java.lang.String(data_row.value, "UTF8")
print "The fetched row contains the value '%s'" % data
# Delete the table.
admin.disableTable(desc.getName())
admin.deleteTable(desc.getName())
----
====
.Table Scan Using Jython
====
This example scans a table and returns the results that match a given family qualifier.
[source, jython]
----
# Print all rows that are members of a particular column family
# by passing a regex for family qualifier
import java.lang
from org.apache.hadoop.hbase import HBaseConfiguration
from org.apache.hadoop.hbase.client import HTable
conf = HBaseConfiguration()
table = HTable(conf, "wiki")
col = "title:.*$"
scanner = table.getScanner([col], "")
while 1:
result = scanner.next()
if not result:
break
print java.lang.String(result.row), java.lang.String(result.get('title:').value)
----
====