04_第四章 Hadoop数据压缩
作者：互联网
1. 01 Map输出设置压缩 案例
package ComMapOutPk {
import java.lang
import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.fs.Path
import org.apache.hadoop.io.compress.{BZip2Codec, GzipCodec, SnappyCodec}
import org.apache.hadoop.io.{IntWritable, LongWritable, Text}
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat
import org.apache.hadoop.mapreduce.{Job, Mapper, Reducer}
import org.apache.hadoop.io.compress.CompressionCodec
// Mapper 类
// 每个Mapper类实例 处理一个切片文件
class WCMapper extends Mapper[LongWritable, Text, Text, IntWritable] {
var text = new Text
var intWritable = new IntWritable(1)
// 每行记录调用一次map方法
override def map(key: LongWritable, value: Text, context: Mapper[LongWritable, Text, Text, IntWritable]#Context) = {
println("map enter .....")
//1. 获取一行记录
val line = value.toString
//2. 切割
val words = line.split(" ")
//3. 输出到缓冲区
words.foreach(
key1 => {
text.set(key1);
context.write(text, intWritable)
}
)
}
}
// Reducer 类
// 所有Mapper实例 执行完毕后 Reducer才会执行
// Mapper类的输出类型 = Reducer类的输入类型
class WCReducer extends Reducer[Text, IntWritable, Text, IntWritable] {
private val intWritable = new IntWritable
// 每个key调用一次
// 张飞 <1,1,1,1,1>
override def reduce(key: Text, values: lang.Iterable[IntWritable], context: Reducer[Text, IntWritable, Text, IntWritable]#Context) = {
println("reduce enter .....")
var sum: Int = 0
// 1. 对词频数 求sum
values.forEach(sum += _.get)
// 2. 输出结果
intWritable.set(sum)
context.write(key, intWritable)
}
}
// Driver
object Driver {
def main(args: Array[String]): Unit = {
//1. 获取配置信息以及 获取job对象
//读取配置文件 Configuration: core-default.xml, core-site.xml
var configuration = new Configuration
// configuration.set("mapreduce.map.output.compress","true")
// configuration.set("mapreduce.map.output.compression.codec","org.apache.hadoop.io.compress.GzipCodec")
//开启map端输出压缩
configuration.set("mapreduce.map.output.compress","true")
//指定map端输出压缩算法
//configuration.setClass("mapreduce.map.output.compress.codec",classOf[BZip2Codec],classOf[CompressionCodec]);
configuration.setClass("mapreduce.map.output.compress.codec",classOf[org.apache.hadoop.io.compress.BZip2Codec],classOf[CompressionCodec]);
//INFO [org.apache.hadoop.io.compress.CodecPool] - Got brand-new compressor [.bz2]、[.gz]
var job: Job = Job.getInstance(configuration)
//2. 注册本Driver程序的jar
job.setJarByClass(this.getClass)
job.setJobName("compress mr")
//3. 注册 Mapper 和 Reducer的jar
job.setMapperClass(classOf[WCMapper])
job.setReducerClass(classOf[WCReducer])
//4. 设置Mapper 类输出key-value 数据类型
job.setMapOutputKeyClass(classOf[Text])
job.setMapOutputValueClass(classOf[IntWritable])
//5. 设置最终输出key-value 数据类型
job.setOutputKeyClass(classOf[Text])
job.setOutputValueClass(classOf[IntWritable])
//6. 设置输入输出路径
FileInputFormat.setInputPaths(job, "src/main/data/input/1.txt")
FileOutputFormat.setOutputPath(job, new Path("src/main/data/output"))
//7. 提交job
val bool: Boolean = job.waitForCompletion(true)
System.exit(bool match {
case true => "0".toInt
case false => "1".toInt
})
}
}
}
2. 02 Reduce输出设置压缩 案例
/**
* @author gaocun
* @create 2022-01-06 8:10 PM */
package ComReduceOutPk {
import java.lang
import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.fs.Path
import org.apache.hadoop.io.compress.{BZip2Codec, GzipCodec, SnappyCodec}
import org.apache.hadoop.io.{IntWritable, LongWritable, Text}
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat
import org.apache.hadoop.mapreduce.{Job, Mapper, Reducer}
import org.apache.hadoop.io.compress.CompressionCodec
// Mapper 类
// 每个Mapper类实例 处理一个切片文件
class WCMapper extends Mapper[LongWritable, Text, Text, IntWritable] {
var text = new Text
var intWritable = new IntWritable(1)
// 每行记录调用一次map方法
override def map(key: LongWritable, value: Text, context: Mapper[LongWritable, Text, Text, IntWritable]#Context) = {
println("map enter .....")
//1. 获取一行记录
val line = value.toString
//2. 切割
val words = line.split(" ")
//3. 输出到缓冲区
words.foreach(
key1 => {
text.set(key1);
context.write(text, intWritable)
}
)
}
}
// Reducer 类
// 所有Mapper实例 执行完毕后 Reducer才会执行
// Mapper类的输出类型 = Reducer类的输入类型
class WCReducer extends Reducer[Text, IntWritable, Text, IntWritable] {
private val intWritable = new IntWritable
// 每个key调用一次
// 张飞 <1,1,1,1,1>
override def reduce(key: Text, values: lang.Iterable[IntWritable], context: Reducer[Text, IntWritable, Text, IntWritable]#Context) = {
println("reduce enter .....")
var sum: Int = 0
// 1. 对词频数 求sum
values.forEach(sum += _.get)
// 2. 输出结果
intWritable.set(sum)
context.write(key, intWritable)
}
}
// Driver
object Driver {
def main(args: Array[String]): Unit = {
//1. 获取配置信息以及 获取job对象
//读取配置文件 Configuration: core-default.xml, core-site.xml
var configuration = new Configuration
var job: Job = Job.getInstance(configuration)
//2. 注册本Driver程序的jar
job.setJarByClass(this.getClass)
job.setJobName("compress mr")
//3. 注册 Mapper 和 Reducer的jar
job.setMapperClass(classOf[WCMapper])
job.setReducerClass(classOf[WCReducer])
//4. 设置Mapper 类输出key-value 数据类型
job.setMapOutputKeyClass(classOf[Text])
job.setMapOutputValueClass(classOf[IntWritable])
//5. 设置最终输出key-value 数据类型
job.setOutputKeyClass(classOf[Text])
job.setOutputValueClass(classOf[IntWritable])
//6. 设置输入输出路径
FileInputFormat.setInputPaths(job, "src/main/data/input/1.txt")
FileOutputFormat.setOutputPath(job, new Path("src/main/data/output"))
//7. reduce 输出设置压缩
//开启reduce端输出压缩
FileOutputFormat.setCompressOutput(job, true)
//指定reduce端输出压缩算法
//FileOutputFormat.setOutputCompressorClass(job,classOf[BZip2Codec])
//FileOutputFormat.setOutputCompressorClass(job,classOf[GzipCodec])
//7. 提交job
val bool: Boolean = job.waitForCompletion(true)
System.exit(bool match {
case true => "0".toInt
case false => "1".toInt
})
}
}
}
标签：IntWritable,04,Text,Hadoop,hadoop,job,apache,org,数据压缩 来源： https://www.cnblogs.com/bajiaotai/p/15868590.html