【转】Hbase Java编程实例
http://blog.sina.com.cn/s/blog_8c6d7ff60100zexn.html
一、HBase Java API：
1. HbaseConfiguration
关系：org.apache.hadoop.hbase.HBaseConfiguration
作用：通过此类可以对HBase进行配置
2.HBaseAdmin
关系：org.apache.hadoop.hbase.client.HBaseAdmin
作用：提供一个接口来管理HBase数据库中的表信息。它提供创建表、删除表等方法。
3.HTableDescriptor
关系：org.apache.hadoop.hbase.client.HTableDescriptor
作用：包含了表的名字及其对应列族。 提供的方法有
void addFamily(HColumnDescriptor) 添加一个列族
HColumnDescriptor removeFamily(byte[] column) 移除一个列族
byte[] getName() 获取表的名字
byte[] getValue(byte[] key) 获取属性的值
void setValue(String key,String value) 设置属性的值
4.HColumnDescriptor
关系：org.apache.hadoop.hbase.client.HColumnDescriptor
作用：维护关于列的信息。提供的方法有
byte[] getName() 获取列族的名字
byte[] getValue() 获取对应的属性的值
void setValue(String key,String value) 设置对应属性的值
5.HTable
关系：org.apache.hadoop.hbase.client.HTable
作用：用户与HBase表进行通信。此方法对于更新操作来说是非线程安全的，如果启动多个线程尝试与单个HTable实例进行通信，那么写缓冲器可能会崩溃。
6.Put
关系：org.apache.hadoop.hbase.client.Put
作用：用于对单个行执行添加操作
7.Get
关系：org.apache.hadoop.hbase.client.Get
作用：用于获取单个行的相关信息
8.Result
关系：org.apache.hadoop.hbase.client.Result
作用：存储Get或Scan操作后获取的单行值。
9.ResultScanner
关系：Interface
作用：客户端获取值的接口。
二、示例：
以下是一个完整的代码示例，基于hbase-0.90.3编写
类：HBaseOperation 功能： 创建、删除表，增加、删除、查询记录。类：HBaseTest 功能： 实例化HBaseOperation，使用其相应方法。
2.1 HBaseOperation源码如下：
package model;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
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.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.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
public class HBaseOperation {
//.相关属性
private Configuration conf ;
private HBaseAdmin admin;
public HBaseOperation(Configuration conf) throws IOException{
this.conf=HBaseConfiguration.create(conf);
this.admin =new HBaseAdmin(this.conf);
}
public HBaseOperation() throws IOException{
Configuration cnf = new Configuration();
this.conf=HBaseConfiguration.create(cnf);
this.admin=new HBaseAdmin(this.conf);
}
//1.创建表
public void createTable(String tableName,String colFamilies[]) throws IOException{
if(this.admin.tableExists(tableName)){
System.out.println("Table: "+tableName+" already exists !");
}else{
HTableDescriptor dsc = new HTableDescriptor(tableName);
int len = colFamilies.length;
for(int i=0;i<len;i++){
HColumnDescriptor family = new HColumnDescriptor(colFamilies[i]);
dsc.addFamily(family);
}
admin.createTable(dsc);
System.out.println("创建表成功");
}
}
//2.删除表
public void deleteTable(String tableName) throws IOException{
if(this.admin.tableExists(tableName)){
admin.deleteTable(tableName);
System.out.println("删除表成功");
}else{
System.out.println("Table Not Exists !");
}
}
//3.插入一行记录
public void insertRecord(String tableName,String rowkey,String family,String qualifier,String value) throws IOException {
HTable table = new HTable(this.conf,tableName);
Put put = new Put(rowkey.getBytes());
put.add(family.getBytes(),qualifier.getBytes(),value.getBytes());
table.put(put);
System.out.println("插入行成功");
}
//4.删除一行记录
public void deleteRecord(String tableName,String rowkey) throws IOException{
HTable table = new HTable(this.conf,tableName);
Delete del =new Delete(rowkey.getBytes());
table.delete(del);
System.out.println("删除行成功");
}
//5.获取一行记录
public Result getOneRecord(String tableName,String rowkey) throws IOException{
HTable table =new HTable(this.conf,tableName);
Get get =new Get(rowkey.getBytes());
Result rs = table.get(get);
return rs;
}
//6.获取所有记录
public List<Result> getAllRecord(String tableName) throws IOException{
HTable table = new HTable(this.conf,tableName);
Scan scan = new Scan();
ResultScanner scanner = table.getScanner(scan);
List<Result> list =new ArrayList<Result>();
for(Result r:scanner){
list.add(r);
}
scanner.close();
return list;
}
}
2.2 HBaseTest源码如下：
package model;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.client.Result;
public class HBaseTest {
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
System.out.println("hello veagle and serapy ");
//1.初始化HBaseOperation
Configuration conf = new Configuration();
//与hbase/conf/hbase-site.xml中hbase.zookeeper.quorum配置的值相同
conf.set("hbase.zookeeper.quorum", "172.21.7.124");
//与hbase/conf/hbase-site.xml中hbase.zookeeper.property.clientPort配置的值相同
conf.set("hbase.zookeeper.property.clientPort", "2181");
HBaseOperation hbase = new HBaseOperation(conf);
//2.测试相应操作
//2.1创建表
String tableName = "blog";
String colFamilies[]={"article","author"};
hbase.createTable(tableName, colFamilies);
//2.2插入一条记录
hbase.insertRecord(tableName, "row1", "article", "title", "Hadoop");
hbase.insertRecord(tableName, "row1", "author", "name", "veagle");
hbase.insertRecord(tableName, "row1", "author", "nickname", "serapy");
//2.3查询一条记录
Result rs1 = hbase.getOneRecord(tableName, "row1");
for(KeyValue kv: rs1.raw()){
System.out.println(new String(kv.getRow()));
System.out.println(new String(kv.getFamily()));
System.out.println(new String(kv.getQualifier()));
System.out.println(new String(kv.getValue()));
}
//2.4查询整个Table
List<Result> list =null;
list= hbase.getAllRecord("blog");
Iterator<Result> it = list.iterator();
while(it.hasNext()){
Result rs2=it.next();
for(KeyValue kv : rs2.raw()){
System.out.print("row key is : " + new String(kv.getRow()));
System.out.print("family is : " + new String(kv.getFamily()));
System.out.print("qualifier is:" + new String(kv.getQualifier()));
System.out.print("timestamp is:" + kv.getTimestamp());
System.out.println("Value is : " + new String(kv.getValue()));
}
}
}
}
2.3 执行结果
插入行成功
插入行成功
插入行成功
row1
article
title
Hadoop
row1
author
name
veagle
row1
author
nickname
serapy
row key is : row1family is : articlequalifier is:titletimestamp is:1322728761046Value is : Hadoop
row key is : row1family is : authorqualifier is:nametimestamp is:1322728761056Value is : veagle
row key is : row1family is : authorqualifier is:nicknametimestamp is:1322728761060Value is : serapy
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参考文献
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