HBASE 常用JAVA API使用指南

HBase提供了Java API对其进行管理，包括对表的管理、数据的操作等。

1. HBaseAdmin —— 对表的创建、删除、显示以及修改等；

2. HTable —— 通过HTable的实例来访问表并进行数据的操作，获取表实例如下两种方法：

方法一：直接获取

HTable table = new HTable(config, tableName);

方法二：用表连接池的方式

HTablePool pool = new HTablePool(config,1000);

HTable table = (HTable) pool.getTable(tableName);

3.插入数据：

创建一个Put对象，并指定参数为一个行(Row)值（即指定给哪一列增加数据以及当前的时间戳等值），然后调用HTable.put(Put)。

4.获取数据

创建一个Get对象，在构造的时候传入行值，表示取第几行的数据，然后调用HTable.get(Get)。

5.删除数据

创建一个Delete对象，参数为一个行(Row)值，然后调用HTable.delete(Delete)。

6. 浏览数据

通过Scan可以对表中的行进行浏览，得到每一行的信息，比如列名，时间戳等，Scan相当于一个游标，通过next()来浏览下一个。

通过调用HTable.getScanner(Scan)来返回一个ResultScanner对象。

HTable.get(Get)和HTable.getScanner(Scan)都是返回一个Result。

Result是一个KeyValue的链表,遍历过程当中保存当前行信息。

以下是一个java对hbase的基本操作实例（hadoop-1.0.3 && hbase-0.90.3）

Java代码

package tool;

import java.io.IOException;

import java.util.Scanner;

import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.hbase.HBaseConfiguration;

import org.apache.hadoop.hbase.HColumnDescriptor;

import org.apache.hadoop.hbase.HTableDescriptor;

import org.apache.hadoop.hbase.KeyValue;

import org.apache.hadoop.hbase.client.Delete;

import org.apache.hadoop.hbase.client.Get;

import org.apache.hadoop.hbase.client.HBaseAdmin;

import org.apache.hadoop.hbase.client.HTable;

import org.apache.hadoop.hbase.client.HTablePool;

import org.apache.hadoop.hbase.client.Put;

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.util.Bytes;

public class Hbase {

//initial

static Configuration config = null;

static {

config = HBaseConfiguration.create();

config.set("hbase.zookeeper.quorum", "192.168.21.20, 192.168.21.21, 192.168.21.22");

config.set("hbase.zookeeper.property.clientPort", "2181");

}

//create a new table

public void createTable(String tableName, String[] familys) throws IOException {

HBaseAdmin admin = new HBaseAdmin(config);

if (admin.tableExists(tableName)) {

System.out.println(tableName + " is already exists,Please create another table!");

} else {

HTableDescriptor desc = new HTableDescriptor(tableName);

for (int i = 0; i < familys.length; i++) {

HColumnDescriptor family = new HColumnDescriptor(familys[i]);

desc.addFamily(family);

}

admin.createTable(desc);

System.out.println("Create table \'" + tableName + "\' OK!");

}

}

//delete a table

public void deleteTable(String tableName) throws IOException {

HBaseAdmin admin = new HBaseAdmin(config);

if (!admin.tableExists(tableName)) {

System.out.println(tableName + " is not exists!");

} else {

Scanner s = new Scanner(System.in);

System.out.print("Are you sure to delete(y/n)?");

String str = s.nextLine();

if (str.equals("y") || str.equals("Y")) {

admin.disableTable(tableName);

admin.deleteTable(tableName);

System.out.println(tableName + " is delete!");

} else {

System.out.println(tableName + " is not delete!");

}

}

}

//Get table example

public void getTable(String tableName) throws IOException {

//Method I:

// HTable table = new HTable(config, tableName);

//Method II: better than I.

HTablePool pool = new HTablePool(config,1000);

@SuppressWarnings("unused")

HTable table = (HTable) pool.getTable(tableName);

}

//add a data

public void insertData(String tableName, String rowKey, String family, String qualifier, String value) {

try {

HTablePool pool = new HTablePool(config, 1000);

HTable table = (HTable)pool.getTable(tableName);

Put put = new Put(Bytes.toBytes(rowKey));

put.add(Bytes.toBytes(family), Bytes.toBytes(qualifier), Bytes.toBytes(value));

table.put(put);

System.out.println("insert a data successful!");

} catch (IOException e) {

e.printStackTrace();

}

}

//delete a data

public void deleteData(String tableName, String rowKey) {

try {

HTablePool pool = new HTablePool(config, 1000);

HTable table = (HTable)pool.getTable(tableName);

Delete del = new Delete(Bytes.toBytes(rowKey));

table.delete(del);

System.out.println("delete a data successful");

table.close();

} catch (IOException e) {

e.printStackTrace();

}

}

//Query all data

public void queryAll(String tableName) {

try {

HTablePool pool = new HTablePool(config, 1000);

HTable table = (HTable) pool.getTable(tableName);

Scan scan = new Scan();

ResultScanner scanner = table.getScanner(scan);

for (Result row : scanner) {

System.out.println("\nRowkey: " + new String(row.getRow()));

for (KeyValue kv : row.raw()) {

System.out.print(new String(kv.getRow()) + " "); //same as above

System.out.print(new String(kv.getFamily()) + ":");

System.out.print(new String(kv.getQualifier()) + " = ");

System.out.print(new String(kv.getValue()));

System.out.print(" timestamp = " + kv.getTimestamp() + "\n");

}

}

table.close();

} catch (IOException e) {

e.printStackTrace();

}

}

//query by rowkey

public void queryByRowKey(String tableName, String rowKey) {

try {

HTablePool pool = new HTablePool(config, 1000);

HTable table = (HTable)pool.getTable(tableName);

Get get = new Get(rowKey.getBytes());

Result row = table.get(get);

for (KeyValue kv : row.raw()) {

System.out.print(new String(kv.getRow()) + " ");

System.out.print(new String(kv.getFamily()) + ":");

System.out.print(new String(kv.getQualifier()) + " = ");

System.out.print(new String(kv.getValue()));

System.out.print(" timestamp = " + kv.getTimestamp() + "\n");

}

table.close();

} catch (IOException e) {

e.printStackTrace();

}

}

public static void main(String[] args) throws IOException {

Hbase hbase = new Hbase();

//Create a new table

String tableName = "test";

System.out.println("=======delete table======");

hbase.deleteTable(tableName);

System.out.println("=======create table======");

String[] familys = {"info", "scores"};

hbase.createTable(tableName, familys);

System.out.println("=======insert data=======");

//insert Jim

hbase.insertData(tableName, "Jim", "info", "sex", "male");

hbase.insertData(tableName, "Jim", "info", "age", "18");

hbase.insertData(tableName, "Jim", "scores", "Chinese", "98");

hbase.insertData(tableName, "Jim", "scores", "English", "90");

hbase.insertData(tableName, "Jim", "scores", "Math", "100");

//insert Ann

hbase.insertData(tableName, "Ann", "info", "sex", "female");

hbase.insertData(tableName, "Ann", "info", "age", "18");

hbase.insertData(tableName, "Ann", "scores", "Chinese", "97");

hbase.insertData(tableName, "Ann", "scores", "Math", "95");

System.out.println("=======query all data=======");

hbase.queryAll(tableName);

System.out.println("=======query by rowkey=======");

String rowKey = "Ann";

hbase.queryByRowKey(tableName, rowKey);

System.out.println("=======delete a data=======");

hbase.deleteData(tableName, rowKey);

hbase.queryAll(tableName);

}

}

程序运行结果：

=======delete table======

Are you sure to delete(y/n)?y

test is delete!

=======create table======

Create table 'test' OK!

=======insert data=======

insert a data successful!

=======query all data=======

Rowkey: Ann

Ann info:age = 18 timestamp = 1349857967109

Ann info:sex = female timestamp = 1349857967080

Ann scores:Chinese = 97 timestamp = 1349857967134

Ann scores:Math = 95 timestamp = 1349857967160

Rowkey: Jim

Jim info:age = 18 timestamp = 1349857966936

Jim info:sex = male timestamp = 1349857966908

Jim scores:Chinese = 98 timestamp = 1349857966961

Jim scores:English = 90 timestamp = 1349857967002

Jim scores:Math = 100 timestamp = 1349857967052

=======query by rowkey=======

Ann info:age = 18 timestamp = 1349857967109

Ann info:sex = female timestamp = 1349857967080

Ann scores:Chinese = 97 timestamp = 1349857967134

Ann scores:Math = 95 timestamp = 1349857967160

=======delete a data=======

delete a data successful

Rowkey: Jim

Jim info:age = 18 timestamp = 1349857966936

Jim info:sex = male timestamp = 1349857966908

Jim scores:Chinese = 98 timestamp = 1349857966961

Jim scores:English = 90 timestamp = 1349857967002

Jim scores:Math = 100 timestamp = 1349857967052