102. Jython

102.1. 设置类路径

要将 Jython 与 HBase 一起使用，您的 CLASSPATH 必须包含 HBase 的类路径以及代码所需的 Jython JAR。

将路径设置为包含Jython.jar的目录，以及每个项目需要的附加的 Jython 相关 JAR。然后将的 HBASE_CLASSPATH 指向$JYTHON_HOME 。

$ export HBASE_CLASSPATH=/directory/jython.jar

在类路径中使用 HBase 和 Hadoop JAR 启动 Jython shell: $ bin/hbase org.python.util.jython

102.2. Jython 示例

Example 27. 使用 Jython 创建表，填充，获取和删除表

以下 Jython 代码示例检查表，如果存在，则删除它然后创建它。然后，它使用数据填充表并获取数据。

import java.lang
from org.apache.hadoop.hbase import HBaseConfiguration, HTableDescriptor, HColumnDescriptor, TableName
from org.apache.hadoop.hbase.client import Admin, Connection, ConnectionFactory, Get, Put, Result, Table
from org.apache.hadoop.conf import Configuration

# 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()
connection = ConnectionFactory.createConnection(conf)
admin = connection.getAdmin()

# Create a table named 'test' that has a column family
# named 'content'.
tableName = TableName.valueOf("test")
table = connection.getTable(tableName)

desc = HTableDescriptor(tableName)
desc.addFamily(HColumnDescriptor("content"))

# Drop and recreate if it exists
if admin.tableExists(tableName):
    admin.disableTable(tableName)
    admin.deleteTable(tableName)

admin.createTable(desc)

# Add content to 'column:' on a row named 'row_x'
row = 'row_x'
put = Put(row)
put.addColumn("content", "qual", "some content")
table.put(put)

# Now fetch the content just added, returns a byte[]
get = Get(row)

result = table.get(get)
data = java.lang.String(result.getValue("content", "qual"), "UTF8")

print "The fetched row contains the value '%s'" % data

Example 28. 使用 Jython 进行表扫描

此示例扫描表并返回与给定族限定符匹配的结果。

import java.lang
from org.apache.hadoop.hbase import TableName, HBaseConfiguration
from org.apache.hadoop.hbase.client import Connection, ConnectionFactory, Result, ResultScanner, Table, Admin
from org.apache.hadoop.conf import Configuration
conf = HBaseConfiguration.create()
connection = ConnectionFactory.createConnection(conf)
admin = connection.getAdmin()
tableName = TableName.valueOf('wiki')
table = connection.getTable(tableName)

cf = "title"
attr = "attr"
scanner = table.getScanner(cf)
while 1:
    result = scanner.next()
    if not result:
       break
    print java.lang.String(result.row), java.lang.String(result.getValue(cf, attr))