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MapReduce高级

1-MapReduce-计数器

SortMapper.java

package com.mapreduce_sort;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Counter;
import org.apache.hadoop.mapreduce.Mapper;

public class SortMapper extends Mapper<LongWritable, Text, PairWritable, Text>{
@Override
protected void map(LongWritable key, Text value,Context context) throws IOException, InterruptedException {
//自定义计数器
Counter counter = context.getCounter("MR_COUNT", "MapReduceCounter");//类型:"MR_COUNT", 变量:"MapReduceCounter"
counter.increment(1L);//1L为每次执行map方法就计数一次信息,L为long类型

//1.对每一行数据进行拆分,然后封装到PairWritable对象中,作为A2
String[] split = value.toString().split(" ");
PairWritable pairWritable = new PairWritable();
pairWritable.setFirst(split[0]);
pairWritable.setSecond(Integer.parseInt(split[1].trim()));

//2.将k2和v2写入上下文中
context.write(pairWritable, value);
}
}

SortReduce.java

package com.mapreduce_sort;

import java.io.IOException;

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

public class SortReducer extends Reducer<PairWritable,Text, PairWritable, NullWritable>{

/**
* a 1 <a 1,a 1>
* a 1
*
*/
//自定义计数器:使用枚举
public static enum MyCounter{//定义了两个计数器
REDUCE_INPUT_KEY_RECORDS,REDUCE_INPUT_VALUE_RECORDS
}

@Override
protected void reduce(PairWritable key, Iterable<Text> values,Context context)throws IOException, InterruptedException {
//统计Reduce阶段key的个数
context.getCounter(MyCounter.REDUCE_INPUT_KEY_RECORDS).increment(1L);

//处理有两个a 1
for (Text value : values) {
//统计Reduce阶段value的个数
context.getCounter(MyCounter.REDUCE_INPUT_VALUE_RECORDS).increment(1L);

//NullWritable.get();.get()表示获取空对象
context.write(key, NullWritable.get());
}
}
}

====================================================================================================================================================

2-MapReduce-Combiner规约-原理分析

============================================================================================================================================

3-MapReduce-Combiner规约-代码实现

WordCountMapper.java

package com.mapreduce_combiner;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

/**
* Mapper的泛型:
* KEYIN:k1的类型有偏移量 LongWritable
* VALUEIN:v1的类型一行的文本数据 Text
* KEYOUT:k2的类型每个单词 Text
* VALUEOUT:v2的类型固定值1 LongWritable
*
*/
public class WordCountMapper extends Mapper<LongWritable, Text, Text, LongWritable>{
/**
* map方法是将k1和v1转为k2和v2
* key:是k1
* value:是v1
* context:表示MapReduce上下文对象
*/
/**
* k1 v1
* 0 hello,world
* 11 hello,hadoop
* ------------------------------------------
* k2 v2
* hello 1
* world 1
* hadoop 1
*/
@Override
protected void map(LongWritable key, Text value,Context context) throws IOException, InterruptedException {
Text text=new Text();
LongWritable writable = new LongWritable();
//1.对每一行数据进行字符串拆分
String line = value.toString();
String[] split = line.split(",");
//2.遍历数组,获取一个单词

//靠context来连接
for (String word : split) {
text.set(word);
writable.set(1);
context.write(text,writable);
}
}
}

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

WordCountReducer.java

package com.mapreduce_combiner;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

/**
* KEYIN:k2 Text 每个单词
* VALUE:v2 LongWritable 集合中泛型的类型
* KEYOUT:k3 Text 每个单词
* VALUEOUT LongWritable 每个单词出现的次数
*/
public class WordCountReducer extends Reducer<Text, LongWritable, Text, LongWritable>{
/**
* reduce方法的作用是将k2和v2转为k3和v3
* key:k2
* value:集合
* context:MapReduce的上下文对象
*/
/**
* 新 k2 v2
* hello <1,1>
* world <1,1>
* hadoop <1,1,1>
* -----------------------------
* k3 v3(遍历集合相加)
* hello 2
* world 2
* hadoop 3
*/
@Override
protected void reduce(Text key, Iterable<LongWritable> values,
Context context) throws IOException, InterruptedException {
long count=0;
//1.遍历values集合
for (LongWritable value : values) {
//2.将集合中的值相加
count+=value.get();

}
//3:将k3和v3写入上下文中
context.write(key, new LongWritable(count));
}
}

==========================================================================================================

MyCombiner.java

package com.mapreduce_combiner;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

//规约(减少网络传输数据量,提高网络传输效率)
public class MyCombiner extends Reducer<Text, LongWritable, Text, LongWritable>{
@Override
protected void reduce(Text key, Iterable<LongWritable> values,
Context context) throws IOException, InterruptedException {
long count=0;
//1.遍历values集合
for (LongWritable value : values) {
//2.将集合中的值相加
count+=value.get();

}
//3:将k3和v3写入上下文中
context.write(key, new LongWritable(count));
}

}

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

JobMain.java

package com.mapreduce_combiner;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class JobMain extends Configured implements Tool{

@Override
public int run(String[] arg0) throws Exception {
//创建一个任务对象
Job job = Job.getInstance(super.getConf(),"mapreduce_wordcount");

//打包在集群运行时,需要做一个配置
job.setJarByClass(JobMain.class);

//设置任务对象
//第一步:设置读取文件的类:K1和V1(读取原文件TextInputFormat)
job.setInputFormatClass(TextInputFormat.class);
//设置从哪里读
TextInputFormat.addInputPath(job,new Path("hdfs://node01:8020/wordcount"));
//第二步：设置Mapper类
job.setMapperClass(WordCountMapper.class);
//设置Map阶段的输出类型： k2和v2的类型
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(LongWritable.class);
//进入Shuffle阶段,采取默认分区,默认排序,默认规约,默认分组
//第三,四,五,六步,采取默认分区,默认排序,默认规约,默认分组
//设置我们的规约类
job.setCombinerClass(MyCombiner.class);

//第七步:设置Reducer类
job.setReducerClass(WordCountReducer.class);
//设置reduce阶段的输出类型
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(LongWritable.class);

//第八步: 设置输出类
job.setOutputFormatClass(TextOutputFormat.class);
//设置输出的路径
//注意:wordcount_out这个文件夹一定不能存在
TextOutputFormat.setOutputPath(job, new Path("hdfs://node01:8020/wordcount_combiner"));

boolean b= job.waitForCompletion(true);//固定写法;一旦任务提交,处于等待任务完成状态
return b?0:1;
}

public static void main(String[] args) throws Exception {
Configuration configuration = new Configuration();
//启动一个任务
//返回值0:执行成功
int run = ToolRunner.run(configuration, new JobMain(), args);
System.out.println(run);
}
}

加入规约代码后执行截图:

===================================================================================================================================================

4-MapReduce-流量统计求和-步骤分析(手机流量统计案例)

data_flow.dat

1363157985066 13726230503 00-FD-07-A4-72-B8:CMCC 120.196.100.82 i02.c.aliimg.com 游戏娱乐 24 27 2481 24681 200
1363157995052 13826544101 5C-0E-8B-C7-F1-E0:CMCC 120.197.40.4 jd.com 京东购物 4 0 264 0 200
1363157991076 13926435656 20-10-7A-28-CC-0A:CMCC 120.196.100.99 taobao.com 淘宝购物 2 4 132 1512 200
1363154400022 13926251106 5C-0E-8B-8B-B1-50:CMCC 120.197.40.4 cnblogs.com 技术门户 4 0 240 0 200
1363157993044 18211575961 94-71-AC-CD-E6-18:CMCC-EASY 120.196.100.99 iface.qiyi.com 视频网站 15 12 1527 2106 200
1363157995074 84138413 5C-0E-8B-8C-E8-20:7DaysInn 120.197.40.4 122.72.52.12 未知 20 16 4116 1432 200
1363157993055 13560439658 C4-17-FE-BA-DE-D9:CMCC 120.196.100.99 sougou.com 综合门户 18 15 1116 954 200
1363157995033 15920133257 5C-0E-8B-C7-BA-20:CMCC 120.197.40.4 sug.so.360.cn 信息安全 20 20 3156 2936 200
1363157983019 13719199419 68-A1-B7-03-07-B1:CMCC-EASY 120.196.100.82 baidu.com 综合搜索 4 0 240 0 200
1363157984041 13660577991 5C-0E-8B-92-5C-20:CMCC-EASY 120.197.40.4 s19.cnzz.com 站点统计 24 9 6960 690 200
1363157973098 15013685858 5C-0E-8B-C7-F7-90:CMCC 120.197.40.4 rank.ie.sogou.com 搜索引擎 28 27 3659 3538 200
1363157986029 15989002119 E8-99-C4-4E-93-E0:CMCC-EASY 120.196.100.99 www.umeng.com 站点统计 3 3 1938 180 200
1363157992093 13560439658 C4-17-FE-BA-DE-D9:CMCC 120.196.100.99 zhilian.com 招聘门户 15 9 918 4938 200
1363157986041 13480253104 5C-0E-8B-C7-FC-80:CMCC-EASY 120.197.40.4 csdn.net 技术门户 3 3 180 180 200
1363157984040 13602846565 5C-0E-8B-8B-B6-00:CMCC 120.197.40.4 2052.flash2-http.qq.com 综合门户 15 12 1938 2910 200
1363157995093 13922314466 00-FD-07-A2-EC-BA:CMCC 120.196.100.82 img.qfc.cn 图片大全 12 12 3008 3720 200
1363157982040 13502468823 5C-0A-5B-6A-0B-D4:CMCC-EASY 120.196.100.99 y0.ifengimg.com 综合门户 57 102 7335 110349 200
1363157986072 18320173382 84-25-DB-4F-10-1A:CMCC-EASY 120.196.100.99 input.shouji.sogou.com 搜索引擎 21 18 9531 2412 200
1363157990043 13925057413 00-1F-64-E1-E6-9A:CMCC 120.196.100.55 t3.baidu.com 搜索引擎 69 63 11058 48243 200
1363157988072 13760778710 00-FD-07-A4-7B-08:CMCC 120.196.100.82 http://youku.com/ 视频网站 2 2 120 120 200
1363157985079 13823070001 20-7C-8F-70-68-1F:CMCC 120.196.100.99 img.qfc.cn 图片浏览 6 3 360 180 200
1363157985069 13600217502 00-1F-64-E2-E8-B1:CMCC 120.196.100.55 www.baidu.com 综合门户 18 138 1080 186852 200

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

只关心手机号和包数和流量

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

流程图:

==============================================================================================================================

5-MapReduce-流量统计求和-FlowBean和Mapper代码编写

FlowCountMapper.java

package com.mapreduce_flowcount;

import java.io.IOException;

import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;

public class FlowCountMapper extends Mapper<LongWritable, Text, Text, FlowBean> {
@Override
protected void map(LongWritable key, Text value,Context context)
throws IOException, InterruptedException {
//1.拆分手机号
String[] split = value.toString().split(" ");
String phoneNum=split[1];
//2.获取四个流量字段
FlowBean flowBean = new FlowBean();
flowBean.setUpFlow(Integer .parseInt(split[6]));
flowBean.setDownFlow(Integer .parseInt(split[7]));
flowBean.setUpCountFlow(Integer .parseInt(split[8]));
flowBean.setDownCountFlow(Integer .parseInt(split[9]));

//3.将k2和v2写入上下文中
context.write(new Text(phoneNum), flowBean);
}
}

------------------------------------------------------------------------------------------------------------------------------------------------------------------

FlowCountReducer.java

package com.mapreduce_flowcount;

import java.io.IOException;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;

public class FlowCountReducer extends Reducer<Text, FlowBean, Text, FlowBean> {
@Override
protected void reduce(Text key, Iterable<FlowBean> values, Context context)
throws IOException, InterruptedException {
//封装新的FlowBean
FlowBean flowBean = new FlowBean();
Integer upFlow = 0; // 上行包
Integer downFlow = 0; // 下行包
Integer upCountFlow = 0; // 上行流量
Integer downCountFlow = 0;// 下行流量

for (FlowBean value : values) {
upFlow += value.getUpFlow();
downFlow += value.getDownFlow();
upCountFlow += value.getUpCountFlow();
downCountFlow += value.getDownCountFlow();
}
flowBean.setUpFlow(upFlow);
flowBean.setDownFlow(downFlow);
flowBean.setUpCountFlow(upCountFlow);
flowBean.setDownCountFlow(downCountFlow);

//将k3和v3写入上下文中
context.write(key, flowBean);
}

}

------------------------------------------------------------------------------------------------------------------------------------------

FlowBean.java

package com.mapreduce_flowcount;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;

import org.apache.hadoop.io.Writable;

public class FlowBean implements Writable{
private Integer upFlow; //上行包
private Integer downFlow; //下行包
private Integer upCountFlow; //上行流量
private Integer downCountFlow;//下行流量
public Integer getUpFlow() {
return upFlow;
}
public void setUpFlow(Integer upFlow) {
this.upFlow = upFlow;
}
public Integer getDownFlow() {
return downFlow;
}
public void setDownFlow(Integer downFlow) {
this.downFlow = downFlow;
}
public Integer getUpCountFlow() {
return upCountFlow;
}
public void setUpCountFlow(Integer upCountFlow) {
this.upCountFlow = upCountFlow;
}
public Integer getDownCountFlow() {
return downCountFlow;
}
public void setDownCountFlow(Integer downCountFlow) {
this.downCountFlow = downCountFlow;
}
//序列化格式的时候调用toString方法
@Override
public String toString() {
return upFlow + " " + downFlow + " " + upCountFlow + " " + downCountFlow;
}
//反序列化
@Override
public void readFields(DataInput dataInput) throws IOException {
this.upFlow=dataInput.readInt();
this.downFlow=dataInput.readInt();
this.upCountFlow=dataInput.readInt();
this.downCountFlow=dataInput.readInt();
}
//序列化
@Override
public void write(DataOutput dataOutput) throws IOException {
dataOutput.writeInt(upFlow);
dataOutput.writeInt(downFlow);
dataOutput.writeInt(upCountFlow);
dataOutput.writeInt(downCountFlow);
}
}

-----------------------------------------------------------------------------------------------------------------------------------------

JobMain.java

package com.mapreduce_flowcount;

import java.io.InputStream;
import java.io.OutputStream;
import java.util.Set;

import javax.lang.model.SourceVersion;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class JobMain extends Configured implements Tool{

@Override
public int run(String[] arg0) throws Exception {
//创建一个任务对象
Job job = Job.getInstance(super.getConf(),"mapreduce_flowcount");

//打包在集群运行时,需要做一个配置
job.setJarByClass(JobMain.class);

//设置任务对象
//第一步:设置读取文件的类:K1和V1(读取原文件TextInputFormat)
job.setInputFormatClass(TextInputFormat.class);
//设置从哪里读
TextInputFormat.addInputPath(job,new Path("hdfs://node01:8020/input/flowcount"));
//第二步：设置Mapper类
job.setMapperClass(FlowCountMapper.class);
//设置Map阶段的输出类型： k2和v2的类型
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(FlowBean.class);
//进入Shuffle阶段,采取默认分区,默认排序,默认规约,默认分组
//第三,四,五,六步,采取默认分区,默认排序,默认规约,默认分组

//第七步:设置Reducer类
job.setReducerClass(FlowCountReducer.class);
//设置reduce阶段的输出类型
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(FlowBean.class);

//第八步: 设置输出类
job.setOutputFormatClass(TextOutputFormat.class);
//设置输出的路径
//注意:wordcount_out这个文件夹一定不能存在
TextOutputFormat.setOutputPath(job, new Path("hdfs://node01:8020/out/flowcount_out"));

boolean b= job.waitForCompletion(true);//固定写法;一旦任务提交,处于等待任务完成状态
return b?0:1;
}

public static void main(String[] args) throws Exception {
Configuration configuration = new Configuration();
//启动一个任务
//返回值0:执行成功
int run = ToolRunner.run(configuration, new JobMain(), args);
System.out.println(run);
}

}

-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

==========================================================================================================

11-MapReduce-流量统计求和-分区代码实现(以手机号分区)

复制FlowCount代码修改

FlowPartition.java

package com.flowcount_sort;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Partitioner;

public class FlowPartition extends Partitioner<Text, FlowBean> {

@Override
public int getPartition(Text text, FlowBean flowBean, int i) {
//判断手机号以那个数字开头然后返回不同的分区编号
if (text.toString().startsWith("135")) {
return 0;
} else if (text.toString().startsWith("136")) {
return 1;
} else if (text.toString().startsWith("137")){
return 2;
}else {
return 3;
}
}
}

------------------------------------------------------------------------------------------------------------------------------------------------------------------

Jobmain1.java

package com.flowcount_sort;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
public class JobMain1 extends Configured implements Tool{

@Override
public int run(String[] arg0) throws Exception {
//创建一个任务对象
Job job = Job.getInstance(super.getConf(),"mapreduce_flowcount_partition");

//打包在集群运行时,需要做一个配置
job.setJarByClass(JobMain1.class);

//设置任务对象
//第一步:设置读取文件的类:K1和V1(读取原文件TextInputFormat)
job.setInputFormatClass(TextInputFormat.class);
//设置从哪里读
TextInputFormat.addInputPath(job,new Path("hdfs://node01:8020/input/flowcount"));
//第二步：设置Mapper类
job.setMapperClass(FlowCountMapper.class);
//设置Map阶段的输出类型： k2和v2的类型
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(FlowBean.class);
//进入Shuffle阶段,采取默认分区,默认排序,默认规约,默认分组
//第三,四,五,六步,采取默认分区,默认排序,默认规约,默认分组
//设置分区类
job.setPartitionerClass(FlowPartition.class);
//设置Reduce个数
job.setNumReduceTasks(4);

//第七步:设置Reducer类
job.setReducerClass(FlowCountReducer.class);
//设置reduce阶段的输出类型
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(FlowBean.class);

//第八步: 设置输出类
job.setOutputFormatClass(TextOutputFormat.class);
//设置输出的路径
//注意:wordcount_out这个文件夹一定不能存在
TextOutputFormat.setOutputPath(job, new Path("hdfs://node01:8020/out/flowcount_out_partition"));

boolean b= job.waitForCompletion(true);//固定写法;一旦任务提交,处于等待任务完成状态
return b?0:1;
}

public static void main(String[] args) throws Exception {
Configuration configuration = new Configuration();
//启动一个任务
//返回值0:执行成功
int run = ToolRunner.run(configuration, new JobMain1(), args);
System.out.println(run);
}
}

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

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原文地址：https://www.cnblogs.com/curedfisher/p/12603200.html