Hbase本身是没有分页查询的，我在网上找了很多资料来实现一个分页功能，在这里做了一下记录，分享给大家，有什么不足之处，请尽管指出。废话不多说，看代码。
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 {
// 加载集群配置
config = HBaseConfiguration.create();
config.set("hbase.zookeeper.quorum", "xx.xx.xx");
config.set("hbase.zookeeper.property.clientPort", "2181");
// 创建表池(可伟略提高查询性能，具体说明请百度或官方API)
tp = new HTablePool(config, 10);
}
/*
* 获取hbase的表
*/
publicstatic HTableInterface getTable(StringtableName) {
if (StringUtils.isEmpty(tableName))
returnnull;
returntp.getTable(getBytes(tableName));
}
/* 转换byte数组 */
publicstaticbyte[] getBytes(String str) {
if (str == null)
str= "";
return Bytes.toBytes(str);
}
/**
* 查询数据
* @param tableKey 表标识
* @param queryKey 查询标识
* @param startRow 开始行
* @param paramsMap 参数集合
* @return结果集
*/
publicstatic TBData getDataMap(StringtableName, String startRow,
StringstopRow, Integer currentPage, Integer pageSize)
throws IOException {
List<Map<String, String>>mapList = null;
mapList = new LinkedList<Map<String,String>>();
ResultScanner scanner = null;
// 为分页创建的封装类对象，下面有给出具体属性
TBData tbData = null;
try {
// 获取最大返回结果数量
if (pageSize == null || pageSize == 0L)
pageSize = 100;
if (currentPage == null || currentPage == 0)
currentPage = 1;
// 计算起始页和结束页
IntegerfirstPage = (currentPage - 1) * pageSize;
IntegerendPage = firstPage + pageSize;
// 从表池中取出HBASE表对象
HTableInterfacetable = getTable(tableName);
// 获取筛选对象
Scanscan = getScan(startRow, stopRow);
// 给筛选对象放入过滤器(true标识分页,具体方法在下面)
scan.setFilter(packageFilters(true));
// 缓存1000条数据
scan.setCaching(1000);
scan.setCacheBlocks(false);
scanner= table.getScanner(scan);
int i = 0;
List<byte[]> rowList = new LinkedList<byte[]>();
// 遍历扫描器对象， 并将需要查询出来的数据row key取出
for (Result result : scanner) {
String row = toStr(result.getRow());
if (i >= firstPage && i< endPage) {
rowList.add(getBytes(row));
}
i++;
}
// 获取取出的row key的GET对象
List<Get>getList = getList(rowList);
Result[]results = table.get(getList);
// 遍历结果
for (Result result : results) {
Map<byte[], byte[]> fmap = packFamilyMap(result);
Map<String, String> rmap = packRowMap(fmap);
mapList.add(rmap);
}
// 封装分页对象
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;
}
}
// 获取扫描器对象
privatestatic Scan getScan(String startRow,String stopRow) {
Scan scan = new Scan();
scan.setStartRow(getBytes(startRow));
scan.setStopRow(getBytes(stopRow));
return scan;
}
/**
* 封装查询条件
*/
privatestatic FilterList packageFilters(boolean isPage) {
FilterList filterList = null;
// MUST_PASS_ALL(条件 AND) MUST_PASS_ONE（条件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();
}
/**
* 封装每行数据
*/
privatestatic Map<String, String>packRowMap(Map<byte[], byte[]> dataMap) {
Map<String, String> map = new LinkedHashMap<String, String>();
for (byte[] key : dataMap.keySet()) {
byte[] value = dataMap.get(key);
map.put(toStr(key), toStr(value));
}
return map;
}
/* 根据ROW KEY集合获取GET对象集合 */
privatestatic List<Get> getList(List<byte[]> rowList) {
List<Get> list = new LinkedList<Get>();
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;
}
/**
* 封装配置的所有字段列族
*/
privatestatic Map<byte[], byte[]> packFamilyMap(Result result){
Map<byte[], byte[]> dataMap = null;
dataMap = new LinkedHashMap<byte[], byte[]>();
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 {
// 拿出row key的起始行和结束行
// #<0<9<:
String startRow = "aaaa#";
String stopRow = "aaaa:";
int currentPage = 1;
int pageSize = 20;
// 执行hbase查询
getDataMap("table", startRow, stopRow, currentPage,pageSize);
}
}
class TBData {
private Integer currentPage;
private Integer pageSize;
private Integer totalCount;
private Integer totalPage;
private List<Map<String, String>> resultList;
public Integer getCurrentPage() {
returncurrentPage;
}
publicvoid setCurrentPage(IntegercurrentPage) {
this.currentPage = currentPage;
}
public Integer getPageSize() {
returnpageSize;
}
publicvoid setPageSize(Integer pageSize) {
this.pageSize = pageSize;
}
public Integer getTotalCount() {
returntotalCount;
}
publicvoid setTotalCount(Integer totalCount){
this.totalCount = totalCount;
}
public Integer getTotalPage() {
returntotalPage;
}
publicvoid setTotalPage(Integer totalPage) {
this.totalPage = totalPage;
}
public List<Map<String, String>> getResultList() {
returnresultList;
}
publicvoidsetResultList(List<Map<String, String>> resultList) {
this.resultList = resultList;
}
}
本文出自 “攻城狮” 博客，请务必保留此出处http://maxli.blog.51cto.com/7023628/1643453
原文地址：http://maxli.blog.51cto.com/7023628/1643453
