转自：http://blog.csdn.net/wind520/article/details/39344805
在HBase中 一个row对应的相同的列只会有一行。使用scan 或get 得到都是最新的数据，如果我们对这某一row所对应的列进行了更改操作后，并不会多生成一条数据，不会像数据库一样，插入时多生成一条记录，在HBase中对同一条数据的修改或插入都只是put操作，最终看到的都是最新的数据，其它的数据在不同的version中保存，默认是隐藏的，通过时间戳区分，Hbase默认保存最近的三个版本，如何才能看到这些旧版本的数据了？
插入测试数据：
hbase(main):026:0> put 'testtable1','row-1','colfam1:qual1','你好，中国'
0 row(s) in 0.0200 seconds
hbase(main):027:0> put 'testtable1','row-1','colfam1:qual1','你好，广州'
0 row(s) in 0.0130 seconds
hbase(main):027:0> put 'testtable1','row-1','colfam1:qual1','welcome，hbase'
0 row(s) in 0.0130 seconds
下面3个命令，只显示最近的三个版本
hbase(main):015:0> get 'testtable1','row-1',{COLUMN=>'colfam1:qual1',VERSIONS=>10}
COLUMN CELL
colfam1:qual1 timestamp=1410943676361, value=welcome\xEF\xBC\x8Chbase
colfam1:qual1 timestamp=1410942935244, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE5\xB9\xBF\xE5\xB7\x9E
colfam1:qual1 timestamp=1410942917285, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE4\xB8\xAD\xE5\x9B\xBD
3 row(s) in 0.0270 seconds
hbase(main):016:0> scan 'testtable1', {COLUMN=>'colfam1:qual1',VERSIONS=>10}
ROW COLUMN+CELL
row-1 column=colfam1:qual1, timestamp=1410943676361, value=welcome\xEF\xBC\x8Chbase
row-1 column=colfam1:qual1, timestamp=1410942935244, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE5\xB9
\xBF\xE5\xB7\x9E
row-1 column=colfam1:qual1, timestamp=1410942917285, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE4\xB8
\xAD\xE5\x9B\xBD
1 row(s) in 0.0300 seconds
hbase(main):017:0> scan 'testtable1', {FILTER => "PrefixFilter ('row-1')",COLUMN=>'colfam1:qual1',VERSIONS=>10}
ROW COLUMN+CELL
row-1 column=colfam1:qual1, timestamp=1410943676361, value=welcome\xEF\xBC\x8Chbase
row-1 column=colfam1:qual1, timestamp=1410942935244, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE5\xB9
\xBF\xE5\xB7\x9E
row-1 column=colfam1:qual1, timestamp=1410942917285, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE4\xB8
\xAD\xE5\x9B\xBD
1 row(s) in 0.0220 seconds
下面2个命令，可以显示所有的版本
hbase(main):018:0> scan 'testtable1',{FILTER => "(QualifierFilter (>=, 'binary:qual1')))",RAW => true, VERSIONS => 10}
ROW COLUMN+CELL
row-1 column=colfam1:qual1, timestamp=1410943676361, value=welcome\xEF\xBC\x8Chbase
row-1 column=colfam1:qual1, timestamp=1410942935244, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE5\xB9
\xBF\xE5\xB7\x9E
row-1 column=colfam1:qual1, timestamp=1410942917285, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE4\xB8
\xAD\xE5\x9B\xBD
row-1 column=colfam1:qual1, timestamp=1410936055137, value=\xE4\xB8\xAD\xE5\x9B\xBD\xE7\xAC\xAC\xE4\xB8
\x89\xE6\x96\xB9\xE7\x9A\x84\xE4\xBA\x8C\xE6\x96\xB9\xE7\x9A\x84
row-1 column=colfam1:qual1, timestamp=1410936031157, value=\xE4\xB8\xAD\xE5\x9B\xBD\xE7\xAC\xAC\xE4\xB8
\x89\xE6\x96\xB9\xE7\x9A\x84
1 row(s) in 0.0290 seconds
hbase(main):019:0> scan 'testtable1',{FILTER => "PrefixFilter ('row-1')",RAW => true, VERSIONS => 10}
ROW COLUMN+CELL
row-1 column=colfam1:qual1, timestamp=1410943676361, value=welcome\xEF\xBC\x8Chbase
row-1 column=colfam1:qual1, timestamp=1410942935244, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE5\xB9
\xBF\xE5\xB7\x9E
row-1 column=colfam1:qual1, timestamp=1410942917285, value=\xE4\xBD\xA0\xE5\xA5\xBD\xEF\xBC\x8C\xE4\xB8
\xAD\xE5\x9B\xBD
row-1 column=colfam1:qual1, timestamp=1410936055137, value=\xE4\xB8\xAD\xE5\x9B\xBD\xE7\xAC\xAC\xE4\xB8
\x89\xE6\x96\xB9\xE7\x9A\x84\xE4\xBA\x8C\xE6\x96\xB9\xE7\x9A\x84
row-1 column=colfam1:qual1, timestamp=1410936031157, value=\xE4\xB8\xAD\xE5\x9B\xBD\xE7\xAC\xAC\xE4\xB8
\x89\xE6\x96\xB9\xE7\x9A\x84
row-1 column=colfam2:col-0, timestamp=1410935938913, value=val-1.0
row-1 column=colfam2:col-1, timestamp=1410935938921, value=val-1.1
row-1 column=colfam2:col-2, timestamp=1410935938927, value=val-1.2
row-1 column=colfam2:col-3, timestamp=1410935938929, value=val-1.3
row-1 column=colfam2:col-4, timestamp=1410935938932, value=val-1.4
row-1 column=colfam2:col-5, timestamp=1410935938935, value=val-1.5
row-1 column=colfam2:col-6, timestamp=1410935938937, value=val-1.6
row-1 column=colfam2:col-7, timestamp=1410935938939, value=val-1.7
row-1 column=colfam2:col-8, timestamp=1410935938941, value=val-1.8
row-1 column=colfam2:col-9, timestamp=1410935938944, value=val-1.9
1 row(s) in 0.0690 seconds
用java代码测试：
package client;
// cc GetExample Example application retrieving data from HBase
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.util.Bytes;
import util.HBaseHelper;
import java.io.IOException;
import org.apache.hadoop.hbase.KeyValue;
import java.util.List;
public class GetExample {
public static void main(String[] args) throws IOException {
// vv GetExample
Configuration conf = HBaseConfiguration.create(); // co GetExample-1-CreateConf Create the configuration.
conf.set("hbase.zookeeper.property.clientPort", "2181");
conf.set("hbase.zookeeper.quorum", "jifeng01");
conf.set("zookeeper.znode.parent", "/hbase");
/*/ ^^ GetExample
HBaseHelper helper = HBaseHelper.getHelper(conf);
if (!helper.existsTable("testtable1")) {
helper.createTable("testtable1", "colfam1");
}
*/
//vv GetExample
HTable table = new HTable(conf, "testtable1"); // co GetExample-2-NewTable Instantiate a new table reference.
Get get = new Get(Bytes.toBytes("row-1")); // co GetExample-3-NewGet Create get with specific row.
get.setMaxVersions();
get.addColumn(Bytes.toBytes("colfam1"), Bytes.toBytes("qual1"));
Result result = table.get(get);
List<KeyValue> list = result.list();
for(final KeyValue kv:list){
// System.out.println("value: "+ kv+ " str: "+Bytes.toString(kv.getValue()));
System.out.println(String.format("row:%s, family:%s, qualifier:%s, qualifiervalue:%s, timestamp:%s.",
Bytes.toString(kv.getRow()),
Bytes.toString(kv.getFamily()),
Bytes.toString(kv.getQualifier()),
Bytes.toString(kv.getValue()),
kv.getTimestamp()));
}
/*
get.addColumn(Bytes.toBytes("colfam1"), Bytes.toBytes("qual1")); // co GetExample-4-AddCol Add a column to the get.
Result result = table.get(get); // co GetExample-5-DoGet Retrieve row with selected columns from HBase.
byte[] val = result.getValue(Bytes.toBytes("colfam1"),
Bytes.toBytes("qual1")); // co GetExample-6-GetValue Get a specific value for the given column.
System.out.println("Value: " + Bytes.toString(val)); // co GetExample-7-Print Print out the value while converting it back.
*/
// ^^ GetExample
}
}
输出结果：
row:row-1, family:colfam1, qualifier:qual1, qualifiervalue:welcome，hbase, timestamp:1410943676361.
row:row-1, family:colfam1, qualifier:qual1, qualifiervalue:你好，广州, timestamp:1410942935244.
row:row-1, family:colfam1, qualifier:qual1, qualifiervalue:你好，中国, timestamp:1410942917285.
