Shulou(Shulou.com)06/01 Report--

Hbase itself is not paged query, I found a lot of information on the Internet to achieve a paging function, here to make a record, share with you, if there are any deficiencies, please feel free to point out. Don't talk much nonsense, look at the code.

Import java.io.IOException

Import java.util.LinkedHashMap

Import java.util.LinkedList

Import java.util.List

Import java.util.Map

Import org.apache.commons.lang.StringUtils

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.HTableInterface

Import org.apache.hadoop.hbase.client.HTablePool

Import org.apache.hadoop.hbase.client.Result

Import org.apache.hadoop.hbase.client.ResultScanner

Import org.apache.hadoop.hbase.client.Scan

Import org.apache.hadoop.hbase.filter.CompareFilter.CompareOp

Import org.apache.hadoop.hbase.filter.Filter

Import org.apache.hadoop.hbase.filter.FilterList

Import org.apache.hadoop.hbase.filter.FirstKeyOnlyFilter

Import org.apache.hadoop.hbase.filter.SingleColumnValueFilter

Import org.apache.hadoop.hbase.util.Bytes

Publicclass HBaseUtils {

Privatestatic Configuration config = null

Privatestatic HTablePool tp = null

Static {

/ / load cluster configuration

Config = HBaseConfiguration.create ()

Config.set ("hbase.zookeeper.quorum", "xx.xx.xx")

Config.set ("hbase.zookeeper.property.clientPort", "2181")

/ / create a table pool (can slightly improve query performance, please ask Baidu or official API for details)

Tp = new HTablePool (config, 10)

}

/ *

* get the table of hbase

, /

Publicstatic HTableInterface getTable (StringtableName) {

If (StringUtils.isEmpty (tableName))

Returnnull

Returntp.getTable (getBytes (tableName))

}

/ * convert byte array * /

Publicstaticbyte [] getBytes (String str) {

If (str = = null)

Str= ""

Return Bytes.toBytes (str)

}

/ * *

* query data

* @ param tableKey table identification

* @ param queryKey query identity

* @ param startRow start line

* @ param paramsMap parameter collection

* @ return result set

, /

Publicstatic TBData getDataMap (StringtableName, String startRow

StringstopRow, Integer currentPage, Integer pageSize)

Throws IOException {

ListmapList = null

MapList = new LinkedList ()

ResultScanner scanner = null

/ / the wrapper class object created for paging. The specific properties are given below.

TBData tbData = null

Try {

/ / get the maximum number of returned results

If (pageSize = = null | | pageSize = = 0L)

PageSize = 100

If (currentPage = = null | | currentPage = = 0)

CurrentPage = 1

/ / calculate the start and end pages

IntegerfirstPage = (currentPage-1) * pageSize

IntegerendPage = firstPage + pageSize

/ / retrieve HBASE table objects from the table pool

HTableInterfacetable = getTable (tableName)

/ / get the filter object

Scanscan = getScan (startRow, stopRow)

/ / put the filter into the filter (true identifies paging, the specific method is below)

Scan.setFilter (packageFilters (true))

/ / cache 1000 pieces of data

Scan.setCaching (1000)

Scan.setCacheBlocks (false)

Scanner= table.getScanner (scan)

Int I = 0

List rowList = new LinkedList ()

/ / traverse the scanner object and row key the data to be queried

For (Result result: scanner) {

String row = toStr (result.getRow ())

If (I > = firstPage & & I < endPage) {

RowList.add (getBytes (row))

}

ITunes +

}

/ / get the GET object of the extracted row key

ListgetList = getList (rowList)

Result [] results = table.get (getList)

/ / traversing the results

For (Result result: results) {

Map fmap = packFamilyMap (result)

Map rmap = packRowMap (fmap)

MapList.add (rmap)

}

/ / encapsulate the paging object

TbData= new TBData ()

TbData.setCurrentPage (currentPage)

TbData.setPageSize (pageSize)

TbData.setTotalCount (I)

TbData.setTotalPage (getTotalPage (pageSize, I))

TbData.setResultList (mapList)

} catch (IOException e) {

E.printStackTrace ()

} finally {

CloseScanner (scanner)

}

Return tbData

}

Privatestaticint getTotalPage (int pageSize, int totalCount) {

Int n = totalCount / pageSize

If (totalCount% pageSize = = 0) {

Return n

} else {

Return ((int) n) + 1

}

}

/ / get the scanner object

Privatestatic Scan getScan (String startRow,String stopRow) {

Scan scan = new Scan ()

Scan.setStartRow (getBytes (startRow))

Scan.setStopRow (getBytes (stopRow))

Return scan

}

/ * *

* encapsulate query conditions

, /

Privatestatic FilterList packageFilters (boolean isPage) {

FilterList filterList = null

/ / MUST_PASS_ALL (conditional AND) MUST_PASS_ONE (conditional OR)

FilterList = new FilterList (FilterList.Operator.MUST_PASS_ALL)

Filter filter1 = null

Filter filter2 = null

Filter1 = newFilter (getBytes ("family1"), getBytes ("column1")

CompareOp.EQUAL, getBytes ("condition1"))

Filter2 = newFilter (getBytes ("family2"), getBytes ("column1")

CompareOp.LESS, getBytes ("condition2"))

FilterList.addFilter (filter1)

FilterList.addFilter (filter2)

If (isPage) {

FilterList.addFilter (new FirstKeyOnlyFilter ())

}

Return filterList

}

Privatestatic Filter newFilter (byte [] f, byte [] c, CompareOp op, byte [] v) {

Returnnew SingleColumnValueFilter (f, c, op,v)

}

Privatestaticvoid closeScanner (ResultScannerscanner) {

If (scanner! = null)

Scanner.close ()

}

/ * *

* encapsulate each row of data

, /

Privatestatic MappackRowMap (Map dataMap) {

Map map = new LinkedHashMap ()

For (byte [] key: dataMap.keySet ()) {

Byte [] value = dataMap.get (key)

Map.put (toStr (key), toStr (value))

}

Return map

}

/ * get the collection of GET objects according to the ROW KEY collection * /

Privatestatic List getList (List rowList) {

List list = new LinkedList ()

For (byte [] row: rowList) {

Getget = new Get (row)

Get.addColumn (getBytes ("family1"), getBytes ("column1"))

Get.addColumn (getBytes ("family1"), getBytes ("column2"))

Get.addColumn (getBytes ("family2"), getBytes ("column1"))

List.add (get)

}

Return list

}

/ * *

* encapsulate all field column families of the configuration

, /

Privatestatic Map packFamilyMap (Result result) {

Map dataMap = null

DataMap = new LinkedHashMap ()

DataMap.putAll (result.getFamilyMap (getBytes ("family1")

DataMap.putAll (result.getFamilyMap (getBytes ("family2")

Return dataMap

}

Privatestatic String toStr (byte [] bt) {

Return Bytes.toString (bt)

}

Publicstaticvoid main (String [] args) throws IOException {

/ / take out the start and end lines of row key

/ / #

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