HBASE-14638 Move Jython info from the Wiki to the Ref Guide
Project: http://git-wip-us.apache.org/repos/asf/hbase/repo Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/9659f140 Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/9659f140 Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/9659f140 Branch: refs/heads/hbase-12439 Commit: 9659f14020b13db010aac1a069b5c2aa7962c867 Parents: 12a718d Author: Misty Stanley-Jones <mstanleyjo...@cloudera.com> Authored: Mon Oct 19 12:03:25 2015 +1000 Committer: Misty Stanley-Jones <mstanleyjo...@cloudera.com> Committed: Mon Nov 2 14:18:13 2015 +1000 ---------------------------------------------------------------------- src/main/asciidoc/_chapters/external_apis.adoc | 120 ++++++++++++++++++-- 1 file changed, 111 insertions(+), 9 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hbase/blob/9659f140/src/main/asciidoc/_chapters/external_apis.adoc ---------------------------------------------------------------------- diff --git a/src/main/asciidoc/_chapters/external_apis.adoc b/src/main/asciidoc/_chapters/external_apis.adoc index 3a08329..3b91c9c 100644 --- a/src/main/asciidoc/_chapters/external_apis.adoc +++ b/src/main/asciidoc/_chapters/external_apis.adoc @@ -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)) ----- \ No newline at end of file +---- +======= +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) +---- +==== \ No newline at end of file
