一、Hbase结合mapreduce
为什么需要用 mapreduce 去访问 hbase 的数据？
——加快分析速度和扩展分析能力
Mapreduce 访问 hbase 数据作分析一定是在离线分析的场景下应用
1、HbaseToHDFS
从 hbase 中读取数据，分析之后然后写入 hdfs，代码实现：
package com.ghgj.hbase.hbase2hdfsmr;
import java.io.IOException;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
/**
* 作用：从hbase中读取user_info这个表的数据，然后写出到hdfs
*/
public class HBaseToHDFSMR {
private static final String ZK_CONNECT = "hadoop03:2181,hadoop04:2181,hadoop05:2181";
public static void main(String[] args) throws Exception {
Configuration conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", ZK_CONNECT);
System.setProperty("HADOOP_USER_NAME", "hadoop");
// conf.set("fs.defaultFS", "hdfs://myha01/");
Job job = Job.getInstance(conf);
job.setJarByClass(HBaseToHDFSMR.class);
Scan scan = new Scan();
scan.addColumn(Bytes.toBytes("base_info"), Bytes.toBytes("name"));
/**
* TableMapReduceUtil：以util结尾：工具
* MapReduceFactory：以factory结尾，它是工厂类，最大作用就是管理对象的生成
*/
TableMapReduceUtil.initTableMapperJob("user_info", scan,
HBaseToHDFSMRMapper.class, Text.class, NullWritable.class, job);
job.setReducerClass(HBaseToHDFSMRReducer.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(NullWritable.class);
Path outputPath = new Path("/hbase2hdfs/output");
FileSystem fs = FileSystem.get(conf);
if(fs.exists(outputPath)){
fs.delete(outputPath);
}
FileOutputFormat.setOutputPath(job, outputPath);
boolean waitForCompletion = job.waitForCompletion(true);
System.exit(waitForCompletion ? 0 : 1);
}
static class HBaseToHDFSMRMapper extends TableMapper<Text, NullWritable>{
/**
* key:rowkey
* value:map方法每执行一次接收到的一个参数，这个参数就是一个Result实例
* 这个Result里面存的东西就是rowkey, family, qualifier, value, timestamp
*/
@Override
protected void map(ImmutableBytesWritable key, Result value, Mapper<ImmutableBytesWritable, Result, Text, NullWritable>.Context context) throws IOException, InterruptedException {
String rowkey = Bytes.toString(key.copyBytes());
System.out.println(rowkey);
List<Cell> cells = value.listCells();
for (int i = 0; i < cells.size(); i++) {
Cell cell = cells.get(i);
String rowkey_result = Bytes.toString(cell.getRow()) + "/t"
+ Bytes.toString(cell.getFamily()) + "/t"
+ Bytes.toString(cell.getQualifier()) + "/t"
+ Bytes.toString(cell.getValue()) + "/t"
+ cell.getTimestamp();
context.write(new Text(rowkey_result), NullWritable.get());
}
}
}
static class HBaseToHDFSMRReducer extends Reducer<Text, NullWritable, Text, NullWritable>{
@Override
protected void reduce(Text key, Iterable<NullWritable> arg1, Reducer<Text, NullWritable, Text, NullWritable>.Context context) throws IOException, InterruptedException {
context.write(key, NullWritable.get());
}
}
}
2、HDFSToHbase
从 hdfs 从读入数据，处理之后写入 hbase，代码实现：
package com.ghgj.hbase.hbase2hdfsmr;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
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.HBaseAdmin;
import org.apache.hadoop.hbase.client.Mutation;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.hbase.mapreduce.TableReducer;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
public class HDFSToHBaseMR {
private static final String ZK_CONNECT = "hadoop03:2181,hadoop04:2181,hadoop05:2181";
private static final String TABLE_NAME = "person_info";
public static void main(String[] args) throws Exception {
Configuration conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", ZK_CONNECT);
System.setProperty("HADOOP_USER_NAME", "hadoop");
Job job = Job.getInstance(conf);
job.setJarByClass(HDFSToHBaseMR.class);
// 以下这一段代码是为了创建一张hbase表叫做 person_info
HBaseAdmin admin = new HBaseAdmin(conf);
HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(TABLE_NAME));
htd.addFamily(new HColumnDescriptor("base_info"));
if (admin.tableExists(TABLE_NAME)) {
admin.disableTable(TABLE_NAME);
admin.deleteTable(TABLE_NAME);
}
admin.createTable(htd);
// 给job指定mapperclass 和 reducerclass
job.setMapperClass(HDFSToHBaseMRMapper.class);
TableMapReduceUtil.initTableReducerJob(TABLE_NAME, HDFSToHBaseMRReducer.class, job);
// 给mapper和reducer指定输出的key-value的类型
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(NullWritable.class);
job.setOutputKeyClass(ImmutableBytesWritable.class);
job.setOutputValueClass(Mutation.class);
// 指定输入数据的路径
FileInputFormat.setInputPaths(job, new Path("/hbase2hdfs/output"));
// job提交
boolean boo = job.waitForCompletion(true);
System.exit(boo ? 0 :1);
}
static class HDFSToHBaseMRMapper extends Mapper<LongWritable, Text, Text, NullWritable> {
@Override
protected void map(LongWritable key, Text value, Mapper<LongWritable, Text, Text, NullWritable>.Context context) throws IOException, InterruptedException {
context.write(value, NullWritable.get());
}
}
/**
* TableReducer extends Reducer 这么做的唯一效果就是把valueout的类型确定为Mutation
*/
static class HDFSToHBaseMRReducer extends TableReducer<Text, NullWritable, ImmutableBytesWritable> {
/**
* baiyc_20150716_0001 base_info name baiyc1 1488348387443
*/
@Override
protected void reduce(Text key, Iterable<NullWritable> values, Reducer<Text, NullWritable, ImmutableBytesWritable, Mutation>.Context context) throws IOException, InterruptedException {
String[] splits = key.toString().split("/t");
String rowkeyStr = splits[0];
ImmutableBytesWritable rowkey = new ImmutableBytesWritable(Bytes.toBytes(rowkeyStr));
Put put = new Put(Bytes.toBytes(rowkeyStr));
String family = splits[1];
String qualifier = splits[2];
String value = splits[3];
String ts = splits[4];
put.add(Bytes.toBytes(family), Bytes.toBytes(qualifier), Long.parseLong(ts), Bytes.toBytes(value));
context.write(rowkey, put);
}
}
}
二、Hbase和mysql数据库数据进行互导
1、mysql数据导入到hbase（用sqoop）
命令：
sqoop import –connect jdbc:mysql://hadoop01/mytest –username root –password root
–table student –hbase-create-table –hbase-table studenttest –column-family name
–hbase-row-key id
其 中 会 报 错 ， 说 Exception in thread “main” java.lang.NoSuchMethodError: org.apache.hadoop.hbase.HTableDescriptor.addFamily(Lorg/apache/hadoop/hbase/HColumnDescriptor;)V 是由于版本不兼容引起，我们可以通过事先创建好表就可以使用了。
请使用下面的命令：
sqoop import –connect jdbc:mysql://hadoop01/mytest –username root –password root
–table student –hbase-table studenttest1 –column-family name –hbase-row-key id
–hbase-create-table 自动在 hbase 中创建表
–column-family name 指定列簇名字
–hbase-row-key id 指定 rowkey 对应的 mysql 当中的键
2、hbase数据导入到mysql
目前没有直接的命令将 Hbase 中的数据导出到 mysql，但是可以先将 hbase 中的数据导 出到 hdfs 中，再将数据导出 mysql
替代方案：
先将 hbase 的数据导入到 hdfs 或者 hive，然后再将数据导入到 mysql
三、hbase整合hive
原理：
Hive 与 HBase 利用两者本身对外的 API 来实现整合，主要是靠 HBaseStorageHandler 进 行通信，利用 HBaseStorageHandler， Hive 可以获取到 Hive 表对应的 HBase 表名，列簇以及 列， InputFormat 和 OutputFormat 类，创建和删除 HBase 表等。
Hive 访问 HBase 中表数据，实质上是通过 MapReduce 读取 HBase 表数据，其实现是在 MR 中，使用 HiveHBaseTableInputFormat 完成对 HBase 表的切分，获取 RecordReader 对象来读 取数据。
对 HBase 表的切分原则是一个 Region 切分成一个 Split,即表中有多少个 Regions,MR 中就有多 少个 Map。
读取 HBase 表数据都是通过构建 Scanner，对表进行全表扫描，如果有过滤条件，则转化为 Filter。当过滤条件为 rowkey 时，则转化为对 rowkey 的过滤， Scanner 通过 RPC 调用 RegionServer 的 next()来获取数据；
1、准备hbase表 数据
create ‘mingxing’,{NAME => ‘base_info’,VERSIONS => 1},{NAME => ‘extra_info’,VERSIONS => 1}
插入数据：
put ‘mingxing’,’rk001′,’base_info:name’,’huangbo’
put ‘mingxing’,’rk001′,’base_info:age’,’33’
put ‘mingxing’,’rk001′,’extra_info:math’,’44’
put ‘mingxing’,’rk001′,’extra_info:province’,’beijing’
put ‘mingxing’,’rk002′,’base_info:name’,’xuzheng’
put ‘mingxing’,’rk002′,’base_info:age’,’44’
put ‘mingxing’,’rk003′,’base_info:name’,’wangbaoqiang’
put ‘mingxing’,’rk003′,’base_info:age’,’55’
put ‘mingxing’,’rk003′,’base_info:gender’,’male’
put ‘mingxing’,’rk004′,’extra_info:math’,’33’
put ‘mingxing’,’rk004′,’extra_info:province’,’tianjin’
put ‘mingxing’,’rk004′,’extra_info:children’,’3′
put ‘mingxing’,’rk005′,’base_info:name’,’liutao’
put ‘mingxing’,’rk006′,’extra_info:name’,’liujialing’
2、hive端操作
三、hbasetohbase byMR
package com.ghgj.hbase.hbase2hdfsmr;
import java.io.IOException;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
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.HBaseAdmin;
import org.apache.hadoop.hbase.client.Mutation;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
import org.apache.hadoop.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.mapreduce.TableReducer;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
public class HBaseToHBaseByMR {
private static final String ZK_CONNECT = "hadoop03:2181,hadoop04:2181,hadoop05:2181";
private static final String OLD_TABLE_NAME = "user_info";
private static final String NEW_TABLE_NAME = "person_info2";
private static final String FAMILY = "base_info";
private static final String QUALIFIER = "age";
public static void main(String[] args) throws Exception {
Configuration conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", ZK_CONNECT);
System.setProperty("HADOOP_USER_NAME", "hadoop");
// conf.set("fs.defaultFS", "hdfs://myha01/");
Job job = Job.getInstance(conf);
job.setJarByClass(HBaseToHDFSMR.class);
// 以下这一段代码是为了创建一张hbase表叫做 person_info
HBaseAdmin admin = new HBaseAdmin(conf);
HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(NEW_TABLE_NAME));
htd.addFamily(new HColumnDescriptor(FAMILY));
if (admin.tableExists(NEW_TABLE_NAME)) {
admin.disableTable(NEW_TABLE_NAME);
admin.deleteTable(NEW_TABLE_NAME);
}
admin.createTable(htd);
Scan scan = new Scan();
scan.addColumn(Bytes.toBytes(FAMILY), Bytes.toBytes(QUALIFIER));
/**
* TableMapReduceUtil：以util结尾：工具
* MapReduceFactory：以factory结尾，它是工厂类，最大作用就是管理对象的生成
*/
TableMapReduceUtil.initTableMapperJob(OLD_TABLE_NAME, scan, HBaseToHBaseByMRMapper.class, Text.class, NullWritable.class, job);
TableMapReduceUtil.initTableReducerJob(NEW_TABLE_NAME, HBaseToHBaseByMRReducer.class, job);
// 给mapper和reducer指定输出的key-value的类型
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(NullWritable.class);
job.setOutputKeyClass(ImmutableBytesWritable.class);
job.setOutputValueClass(Mutation.class);
boolean waitForCompletion = job.waitForCompletion(true);
System.exit(waitForCompletion ? 0 : 1);
}
static class HBaseToHBaseByMRMapper extends TableMapper<Text, NullWritable> {
/**
* key:rowkey value:map方法每执行一次接收到的一个参数，这个参数就是一个Result实例
* 这个Result里面存的东西就是rowkey, family, qualifier, value, timestamp
*/
@Override
protected void map(ImmutableBytesWritable key, Result value, Mapper<ImmutableBytesWritable, Result, Text, NullWritable>.Context context) throws IOException, InterruptedException {
String rowkey = Bytes.toString(key.copyBytes());
System.out.println(rowkey);
List<Cell> cells = value.listCells();
for (int i = 0; i < cells.size(); i++) {
Cell cell = cells.get(i);
String rowkey_result = Bytes.toString(cell.getRow()) + "/t" + Bytes.toString(cell.getFamily()) + "/t" + Bytes.toString(cell.getQualifier()) + "/t" + Bytes.toString(cell.getValue()) + "/t" + cell.getTimestamp();
context.write(new Text(rowkey_result), NullWritable.get());
}
}
}
/**
* TableReducer extends Reducer 这么做的唯一效果就是把valueout的类型确定为Mutation
*/
static class HBaseToHBaseByMRReducer extends TableReducer<Text, NullWritable, ImmutableBytesWritable> {
/**
* baiyc_20150716_0001 base_info name baiyc1 1488348387443
*/
@Override
protected void reduce(Text key, Iterable<NullWritable> values, Reducer<Text, NullWritable, ImmutableBytesWritable, Mutation>.Context context) throws IOException, InterruptedException {
String[] splits = key.toString().split("/t");
String rowkeyStr = splits[0];
ImmutableBytesWritable rowkey = new ImmutableBytesWritable(Bytes.toBytes(rowkeyStr));
Put put = new Put(Bytes.toBytes(rowkeyStr));
String family = splits[1];
String qualifier = splits[2];
String value = splits[3];
String ts = splits[4];
put.add(Bytes.toBytes(family), Bytes.toBytes(qualifier), Long.parseLong(ts), Bytes.toBytes(value));
context.write(rowkey, put);
}
}
}
原创文章，作者：奋斗，如若转载，请注明出处：https://blog.ytso.com/7739.html