h base programming
DESCRIPTION
HBase tutorial to get startedTRANSCRIPT
CreateTablepublic static int VERSION = 5;
public static void createTable(byte[] tableName, byte[][] families,int numVersions) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);HTableDescriptor htableDesc = new HTableDescriptor(tableName);
for (byte[] family : families) {HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(family,
numVersions, HColumnDescriptor.DEFAULT_COMPRESSION,
HColumnDescriptor.DEFAULT_IN_MEMORY,HColumnDescriptor.DEFAULT_BLOCKCACHE,HColumnDescriptor.DEFAULT_TTL,HColumnDescriptor.DEFAULT_BLOOMFILTER);
htableDesc.addFamily(hColumnDescriptor);}hbaseAdmin.createTable(htableDesc);
}
Table Exists & Get Table Namepublic static boolean tableExist(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);return hbaseAdmin.tableExists(tableName);
}public static List<String> getTableNames() throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
List<String> tables = new ArrayList<String>();for (HTableDescriptor htableDesc : hbaseAdmin.listTables()) {
printTableDescriptors(htableDesc);tables.add(htableDesc.getNameAsString());
}return tables;
}public static void printTableDescriptors(HTableDescriptor descriptor) {
System.out.println("Table name " + descriptor.getNameAsString());for (HColumnDescriptor columnDescriptor :
descriptor.getColumnFamilies()) {System.out.println(columnDescriptor.getNameAsString());System.out.println(columnDescriptor.getMaxVersions());System.out.println(columnDescriptor.getMinVersions());
}}
Insert Recordpublic static void insertRecord(HTable htable, byte[] columnFamily,
boolean createColumnFamily,HashMap<String, HashMap<String, String>> creditLogMaps) throws
IOException {String rowKey;// record keyHashMap<String, String> columnData;if (!columnFamilyExist(htable, columnFamily)) {
if (!createColumnFamily)return;
elsecreateColumnFamily(htable, columnFamily,
VERSION);}for (Map.Entry<String, HashMap<String, String>> creditLogMap :
creditLogMaps.entrySet()) {rowKey = creditLogMap.getKey();columnData = creditLogMap.getValue();Put put = new Put(rowKey.getBytes());for (Map.Entry<String, String> kv :
columnData.entrySet()) {put.add(columnFamily, kv.getKey().getBytes(),
kv.getValue().getBytes());
}htable.put(put);System.out.println("Record inserted");
}}
Create Column Familypublic static void createColumnFamily(HTable htable,
byte[] columnFamily,int numVersions) throws IOException {
disableTable(htable.getTableName());
while (isTableEnabled(htable.getTableName()));// wait untill table is disabled
HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(columnFamily, numVersions,HColumnDescriptor.DEFAULT_COMPRESSION,HColumnDescriptor.DEFAULT_IN_MEMORY,HColumnDescriptor.DEFAULT_BLOCKCACHE,HColumnDescriptor.DEFAULT_TTL,HColumnDescriptor.DEFAULT_BLOOMFILTER);
hbaseAdmin.addColumn(htable.getTableName(), hColumnDescriptor);
enableTable(htable.getTableName());}
Get Column Familypublic static List<String> getColumnFamilies(HTable htable) throws IOException {
List<String> columnFamilies = new ArrayList<String>();for (HColumnDescriptor columnDesc :
htable.getTableDescriptor().getColumnFamilies()) {columnFamilies.add(columnDesc.getNameAsString());
}return columnFamilies;
}
public static boolean columnFamilyExist(HTable htable, byte[] columnFamily) throws IOException {
boolean hasColumn = false;if (htable.getTableDescriptor().getFamily(columnFamily) != null) {
hasColumn = true;}return hasColumn;
}
public static boolean isTableEnabled(byte[] tableName) throws IOException {HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);System.out.println("Table enabled " +
hbaseAdmin.isTableEnabled(tableName));return hbaseAdmin.isTableEnabled(tableName);
}
Enable, Disable & Drop Tablepublic static void enableTable(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);hbaseAdmin.enableTable(tableName);
}
public static void disableTable(byte[] tableName) throws IOException {HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);hbaseAdmin.disableTable(tableName);System.out.println("Table " + new String(tableName) + " disabled");
}
public static void dropTable(byte[] tableName) throws IOException {HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);hbaseAdmin.deleteTable(tableName);System.out.println("Table " + new String(tableName) + " deleted");
}
Get Table, Get & Delete Record
public static HTable getTable(byte[] tableName) throws IOException {HBaseConfiguration hbaseConfig = new HBaseConfiguration();HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);return new HTable(hbaseConfig, tableName);
}
public static void deleteRecord(HTable hTable, String rowKey)throws IOException {
Delete delete = new Delete(rowKey.getBytes());hTable.delete(delete);System.out.println("Record " + rowKey + " deleted ");
}
public static PResultSet getRecord(HTable hTable, String rowKey,String family) throws IOException {
Get get = new Get(rowKey.getBytes());get.addFamily(family.getBytes());PResultSet resultSet = new PResultSet(hTable, get);return resultSet;
}
Scan Records• public static void scanRecords(byte[] startKey, HTable hTable)• throws IOException {• Scan scan = new Scan(startKey);• ResultScanner resultScanner = hTable.getScanner(scan);
• System.out.println("#########Scan result ################");• for (Result result : resultScanner) {• System.out.println(">key is " + new
String(result.getRow()));• for (KeyValue kv : result.raw()) {• System.out.println(new
String(kv.getFamily()) + ":"• + new
String(kv.getQualifier()) + " = "• + new
String(kv.getValue()));• }• }• System.out.println("--------Scan result ends
here-------------------");• }
Scan Records by Filterpublic static void scanRecords(byte[] startKey, HTable hTable, TestFilter testFilter) throws IOException {
Scan scan = new Scan(startKey);
scan.setFilter(testFilter.getFilters());ResultScanner resultScanner = hTable.getScanner(scan);System.out.println("#########filter scan result ################");for (Result result : resultScanner) {
System.out.println(">key is " + new String(result.getRow()));
for (KeyValue kv : result.raw()) {System.out.println(new String(kv.getFamily()) +
":"+ new
String(kv.getQualifier()) + " = "+ new
String(kv.getValue()));}
}System.out.println("--------Scan result ends
here-------------------");}
Filter Object
class FilterObject {String columnFamilyName;String columnName;String value;CompareOp compareOp;
public FilterObject(String columnFamilyName, String columnName,String value, CompareOp compareOp) {
this.columnFamilyName = columnFamilyName;this.columnName = columnName;this.value = value;this.compareOp = compareOp;
}}
Filter Classclass TestFilter {
private List<FilterObject> filterObjects;private FilterList filterList;
public TestFilter() {filterObjects = new ArrayList<FilterObject>();filterList = new FilterList();
}
public void addFilterObject(FilterObject ft) {filterObjects.add(ft);
}
public FilterList getFilters() {for (FilterObject filterObject : filterObjects) {
filterList.addFilter(new SingleColumnValueFilter(filterObject.columnFamilyName.getBytes(),filterObject.columnName.getBytes(), filterObject.compareOp,filterObject.value.getBytes()));
}return filterList;
}
}
ResultSetclass PResultSet {
private String tableName;private String columnFamily;private HashMap<String, String> resutlMap;private Result rs;
public PResultSet(HTable hTable, Get get) throws IOException {this.rs = hTable.get(get);this.tableName = hTable.getTableDescriptor().getNameAsString();this.columnFamily = hTable.getTableDescriptor().getColumnFamilies()
.toString();this.resutlMap = new HashMap<String, String>();
}
public String getTableName() {return tableName;
}
public void setTableName(String tableName) {this.tableName = tableName;
}
Cont…
ResultSet cont….public String getColumnFamily() {
return columnFamily;}public void setColumnFamily(String columnFamily) {
this.columnFamily = columnFamily;}public HashMap<String, String> getResutlMap() {
return resutlMap;}public void setResutlMap(HashMap<String, String> resutlMap) {
this.resutlMap = resutlMap;}public String toString() {
System.out.println("TableName :" + getTableName());System.out.println("ColumnFamily : " + getColumnFamily());System.out.println("No Of Rows : " + rs.size());for (KeyValue kv : rs.raw()) {
resutlMap.put(Bytes.toString(kv.getQualifier()),Bytes.toString(kv.getValue()));
}return resutlMap.toString();
}}
Testing Code – Create FunctionsCreate Table Testing:
String tableName = "TrainingDB";String familyName = "CreditLog";
byte[] tableNameBytes = tableName.getBytes();byte[] familyBytes = familyName.getBytes();
byte[][] columnFamilyByteArray = new byte[][] { familyBytes };
if (tableExist(tableNameBytes)) {System.out.println("Table exist");disableTable(tableNameBytes);dropTable(tableNameBytes);
}
createTable(tableNameBytes, columnFamilyByteArray, 5);HTable hTable = getTable(tableNameBytes);System.out.println("Successfully created");System.out.println("Column exist : "
+ columnFamilyExist(hTable, familyBytes));
Testing Code – PutHashMap<String, HashMap<String, String>> creditLogMaps
= new HashMap<String, HashMap<String, String>>();HashMap<String, String> creditLogMap = new HashMap<String,
String>();
creditLogMap.put("Name", "Karthik");creditLogMap.put("Age", "36");creditLogMap.put("Rating", "Good");creditLogMap.put("Limit", "404$");
String rowKey = "1753-4343-4322-5423";creditLogMaps.put(rowKey, creditLogMap);
creditLogMap = new HashMap<String, String>();
creditLogMap.put("Name", "Manik");creditLogMap.put("Age", "36");creditLogMap.put("Rating", "Average");creditLogMap.put("Limit", "-2$");
String rowKey2 = "5557-4343-4322-5422";
creditLogMaps.put(rowKey2, creditLogMap);
insertRecord(hTable, familyBytes, false, creditLogMaps);
Testing Code - PutHashMap<String, String> transLogMap = new HashMap<String, String>();
transLogMap.put("Date", "23-NOV-2011");transLogMap.put("Amount", "$30");transLogMap.put("Balance", "$450");transLogMap.put("Bank", "Barclays");
HashMap<String, HashMap<String, String>> transLogMaps = new HashMap<String, HashMap<String, String>>();
transLogMaps.put(rowKey, transLogMap);insertRecord(hTable, "TransLog".getBytes(), true, transLogMaps);
Testing Code – List TablesSystem.out.println("Tables in HBase");
for (String name : getTableNames()) {System.out.println("# " + name);System.out.println("Table columns");HTable table = getTable(name.getBytes());for (String columnName : getColumnFamilies(table)) {
System.out.println("- " + columnName);}
}
Testing Code – Get & Scan RecordsSystem.out.println(getRecord(hTable, rowKey,
familyName).toString());System.out.println(getRecord(hTable, rowKey,
"TransLog").toString());
scanRecords(rowKey.getBytes(), hTable);
FilterObject filterObject = new FilterObject(familyName, "Age", "36",
CompareOp.EQUAL);FilterObject filterObject2 = new FilterObject(familyName, "Limit",
"-2$", CompareOp.EQUAL);
TestFilter testFilter = new TestFilter();testFilter.addFilterObject(filterObject);testFilter.addFilterObject(filterObject2);
scanRecords(rowKey.getBytes(), hTable, testFilter);
deleteRecord(hTable, rowKey);
System.out.println("After delete");scanRecords(rowKey.getBytes(), hTable);
