Implementation of basic Hbase operations in Java
Wine from a ship
Data store and database Java hbase Hadoop LOG Apache String Exception void PUT
1. Ensure that hbase is enabled. 2
<dependencies> <! -- https://mvnrepository.com/artifact/org.apache.hbase/hbase-client --> <dependency> <groupId>org.apache.hbase</groupId> < artifactId > hbase - client < / artifactId > < version > 1.2.0 < / version > < / dependency > <! -- https://mvnrepository.com/artifact/org.apache.hbase/hbase-server --> <dependency> <groupId>org.apache.hbase</groupId> < artifactId > hbase - server < / artifactId > < version > 1.2.0 < / version > < / dependency >Copy the codeAdd two files to the resources file. 1. Hbase-site.xml
<? The XML version = "1.0"? > <? xml-stylesheet type="text/xsl" href="configuration.xsl"? > <configuration> <property> <name>hbase.zookeeper.quorum</name> <value>master,slave1,slave2</value> <description>The directory shared by RegionServers.</description> </property> <property> <name>hbase.zookeeper.property.clientPort</name> <value>2181</value> </property> </configuration>Copy the code2.log4j.properties
Copy the code # Global logging configuration
log4j.rootLogger=INFO, stdout
# MyBatis logging configuration...
log4j.logger.org
.mybatis.example.BlogMapper=TRACE
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
Copy the code4. Perform basic operations
package com.test.bd17;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.NavigableMap;
import java.util.Random;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellScanner;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.client.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.util.Bytes;
public class HbaseTest {
public Connection connection;
//用hbaseconfiguration初始化配置信息时会自动加载当前应用classpath下的hbase-site.xml
public static Configuration configuration = HBaseConfiguration.create();
public Table table;
public Admin admin;
public HbaseTest() throws Exception{
//对connection初始化
connection = ConnectionFactory.createConnection(configuration);
admin = connection.getAdmin();
}
//创建表
public void createTable(String tablename,String... cf1) throws Exception{
//获取admin对象
Admin admin = connection.getAdmin();
//创建tablename对象描述表的名称信息
TableName tname = TableName.valueOf(tablename);//bd17:mytable
//创建HTableDescriptor对象，描述表信息
HTableDescriptor tDescriptor = new HTableDescriptor(tname);
//判断是否表已存在
if(admin.tableExists(tname)){
System.out.println("表"+tablename+"已存在");
return;
}
//添加表列簇信息
for(String cf:cf1){
HColumnDescriptor famliy = new HColumnDescriptor(cf);
tDescriptor.addFamily(famliy);
}
//调用admin的createtable方法创建表
admin.createTable(tDescriptor);
System.out.println("表"+tablename+"创建成功");
}
//删除表
public void deleteTable(String tablename) throws Exception{
Admin admin = connection.getAdmin();
TableName tName = TableName.valueOf(tablename);
if(admin.tableExists(tName)){
admin.disableTable(tName);
admin.deleteTable(tName);
System.out.println("删除表"+tablename+"成功！");
}else{
System.out.println("表"+tablename+"不存在。");
}
}
//新增数据到表里面Put
public void putData() throws Exception{
TableName tableName = TableName.valueOf("bd17:fromjava");
Table table = connection.getTable(tableName);
Random random = new Random();
List<Put> batPut = new ArrayList<Put>();
for(int i=0;i<10;i++){
//构建put的参数是rowkey rowkey_i (Bytes工具类，各种java基础数据类型和字节数组之间的相互转换)
Put put = new Put(Bytes.toBytes("rowkey_"+i));
put.addColumn(Bytes.toBytes("i"), Bytes.toBytes("username"), Bytes.toBytes("un_"+i));
put.addColumn(Bytes.toBytes("i"), Bytes.toBytes("age"), Bytes.toBytes(random.nextInt(50)+1));
put.addColumn(Bytes.toBytes("i"), Bytes.toBytes("birthday"), Bytes.toBytes("20170"+i+"01"));
put.addColumn(Bytes.toBytes("j"), Bytes.toBytes("phone"), Bytes.toBytes("电话_"+i));
put.addColumn(Bytes.toBytes("j"), Bytes.toBytes("email"), Bytes.toBytes("email_"+i));
//单记录put
// table.put(put);
batPut.add(put);
}
table.put(batPut);
System.out.println("表插入数据成功！");
}
public void getData() throws Exception{
TableName tableName = TableName.valueOf("bd17:fromjava");
table = connection.getTable(tableName);
//构建get对象
List<Get> gets = new ArrayList<Get>();
for(int i=0;i<5;i++){
Get get = new Get(Bytes.toBytes("rowkey_"+i));
gets.add(get);
}
Result[] results = table.get(gets);
for(Result result:results){
//一行一行读取数据
// NavigableMap<byte[],NavigableMap<byte[],NavigableMap<Long,byte[]>>> maps = result.getMap();
// for(byte[] cf:maps.keySet()){
// NavigableMap<byte[],NavigableMap<Long,byte[]>> valueWithColumnQualify = maps.get(cf);
// for(byte[] columnQualify:valueWithColumnQualify.keySet()){
// NavigableMap<Long,byte[]> valueWithTimeStamp = valueWithColumnQualify.get(columnQualify);
// for(Long ts:valueWithTimeStamp.keySet()){
// byte[] value = valueWithTimeStamp.get(ts);
// System.out.println("rowkey:"+Bytes.toString(result.getRow())+",columnFamliy:"+
// Bytes.toString(cf)+",comlumnQualify:"+Bytes.toString(columnQualify)+",timestamp:"
// +new Date(ts)+",value:"+Bytes.toString(value)
// );
// }
// }
// }
//使用字段名称和列簇名称来获取value值
// System.out.println("rowkey:"+Bytes.toString(result.getRow())+",columnfamily:i,columnqualify:username,value:"+
// Bytes.toString(result.getValue(Bytes.toBytes("i"), Bytes.toBytes("username")))
// );
// System.out.println("rowkey:"+Bytes.toString(result.getRow())+",columnfamily:i,columnqualify:age,value:"+
// Bytes.toInt(result.getValue(Bytes.toBytes("i"), Bytes.toBytes("age")))
// );
//使用cell获取result里面的数据
CellScanner cellScanner = result.cellScanner();
while(cellScanner.advance()){
Cell cell = cellScanner.current();
//从单元格cell中把数据获取并输出
//使用 CellUtil工具类，从cell中把数据获取出来
String famliy = Bytes.toString(CellUtil.cloneFamily(cell));
String qualify = Bytes.toString(CellUtil.cloneQualifier(cell));
String rowkey = Bytes.toString(CellUtil.cloneRow(cell));
String value = Bytes.toString(CellUtil.cloneValue(cell));
System.out.println("rowkey:"+rowkey+",columnfamily:"+famliy+",qualify:"+qualify+",value:"+value);
}
}
}
//关闭连接
public void cleanUp() throws Exception{
connection.close();
}
public static void main(String[] args) throws Exception {
HbaseTest hbaseTest = new HbaseTest();
// hbaseTest.createTable("bd17:fromjava", "i","j");
// hbaseTest.deleteTable("bd17:fromjava");
// hbaseTest.putData();
hbaseTest.getData();
hbaseTest.cleanUp();
}
}
Copy the code 
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