一、MapReduce编程规范
一、MapReduce编程规范
用户编写mr程序主要分为三个部分:Mapper,Reducer,Driver
1.Mapper阶段
(1)用户自定义Mapper类 要继承父类Mapper
(2)Mapper的输入数据的kv对形式(kv类型可以自定义)
(3)Mapper的map方法的重写(加入业务逻辑)
(4)Mapper的数据输出kv对的形式(kv类型可以自定义)
(5)map()方法(maptask进程)对每个调用一次
2.Reducer阶段
(1)用户自定义Reducer类 要继承父类Reducer
(2)Reducer的数据输入类型对应的是Mapper阶段的输出数据类型,也是kv对
(3)Reducer的reduce方法的重写(加入业务逻辑)
(4)ReduceTask进程对每组的k的组调用一次reduce方法
3.Driver阶段
MR程序需要一个Driver来进行任务的提交,提交的任务是一个描述了各种重要信息的job对象
4.修改mapred-site.xml文件中加入
mapreduce.framework.name
yarn
二、常用数据序列化类型
1. JAVA 类型 HADOOP 类型
int IntWritable
float FloatWritable
long LongWritable
double DoubleWritable
string Text
boolean BooleanWritable
byte ByteWritable
map MapWritable
array ArrayWritable
2.为什么要序列化?
存储“活的对象”
3.什么是序列化?
序列化就是把内存当中的对象,转换成字节序列以便于存储和网络传输。
反序列化就是将受到的字节序列或者硬盘的持久化数据,转换成内存中的对象。
java的序列化-->Serializable
4.为什么不使用java提供的序列化接口?
java的序列化是一个重量级的序列化框架,一个对象被序列化后会附带很多额外的信息(效验信息,header,继承体系等)。
不便于在网络中高效传输,所以hadoop开发了一套序列化机制(Writable),精简/高效。
5.为什么序列化在hadoop中很重要?
hadoop通信是通过远程调用(rpc)实现的,需要进行序列化
6.特点:
1)紧凑
2)快速
3)可拓展
4)互操作
二、MapReduce分析流量汇总
1.Mapper类
package com.css.flow;
import java.io.IOException;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
/**
* 3631279850362 13726130503 00-FD-07-A4-72-B8:CMCC 120.196.100.82 www.itstaredu.com 教育网站 24 27 299 681 200
* 13726130503 299 681 980
*/
public class FlowCountMapper extends Mapper{
@Override
protected void map(LongWritable key, Text value, Context context)
throws IOException, InterruptedException {
// 1.获取数据
String line = value.toString();
// 2.切割
String[] fields = line.split("\t");
// 3.封装对象 拿到关键字段 数据清洗
String phOneN= fields[1];
long upFlow = Long.parseLong(fields[fields.length - 3]);
long dfFlow = Long.parseLong(fields[fields.length - 2]);
// 4.输出到reduce端
context.write(new Text(phoneN), new FlowBean(upFlow, dfFlow));
}
}
2.Reducer类
package com.css.flow;
import java.io.IOException;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;
public class FlowCountReducer extends Reducer{
@Override
protected void reduce(Text key, Iterable values, Context context)
throws IOException, InterruptedException {
// 1.相同手机号 的流量使用再次汇总
long upFlow_sum = 0;
long dfFlow_sum = 0;
// 2.累加
for (FlowBean f : values) {
upFlow_sum += f.getUpFlow();
dfFlow_sum += f.getDfFlow();
}
FlowBean rs = new FlowBean(upFlow_sum, dfFlow_sum);
// 3.输出
context.write(key, rs);
}
}
3.Driver类
package com.css.flow;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
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.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
public class FlowCountDriver {
public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
// 1.获取job信息
Configuration cOnf= new Configuration();
Job job = Job.getInstance(conf);
// 2.获取jar包
job.setJarByClass(FlowCountDriver.class);
// 3.获取自定义的mapper与reducer类
job.setMapperClass(FlowCountMapper.class);
job.setReducerClass(FlowCountReducer.class);
// 4.设置map输出的数据类型
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(FlowBean.class);
// 5.设置reduce输出的数据类型(最终的数据类型)
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(FlowBean.class);
// 6.设置输入存在的路径与处理后的结果路径
FileInputFormat.setInputPaths(job, new Path("c:/flow1020/in"));
FileOutputFormat.setOutputPath(job, new Path("c:/flow1020/out"));
// 7.提交任务
boolean rs = job.waitForCompletion(true);
System.out.println(rs ? 0 : 1);
}
}
4.封装类,数据的传输
package com.css.flow;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.hadoop.io.Writable;
/**
* 封装类 数据的传输
*/
public class FlowBean implements Writable{
// 定义属性
private long upFlow;
private long dfFlow;
private long flowSum;
public FlowBean() {
}
// 流量累加
public FlowBean(long upFlow, long dfFlow) {
this.upFlow = upFlow;
this.dfFlow = dfFlow;
this.flowSum = upFlow + dfFlow;
}
// 反序列化
@Override
public void readFields(DataInput in) throws IOException {
upFlow = in.readLong();
dfFlow = in.readLong();
flowSum = in.readLong();
}
// 序列化
@Override
public void write(DataOutput out) throws IOException {
out.writeLong(upFlow);
out.writeLong(dfFlow);
out.writeLong(flowSum);
}
@Override
public String toString() {
return upFlow + "\t" + dfFlow + "\t" + flowSum;
}
public long getUpFlow() {
return upFlow;
}
public void setUpFlow(long upFlow) {
this.upFlow = upFlow;
}
public long getDfFlow() {
return dfFlow;
}
public void setDfFlow(long dfFlow) {
this.dfFlow = dfFlow;
}
public long getFlowSum() {
return flowSum;
}
public void setFlowSum(long flowSum) {
this.flowSum = flowSum;
}
}
5.输入的文件HTTP_20180313143750.dat
3631279850362 13726130503 00-FD-07-A4-72-B8:CMCC 120.196.100.82 www.itstaredu.com 教育网站 24 27 299 681 200
3631279950322 13822544101 5C-0E-8B-C7-F1-E0:CMCC 120.197.40.4 www.taobao.com 淘宝网 4 0 264 0 200
3631279910362 13926435656 20-10-7A-28-CC-0A:CMCC 120.196.100.99 2 4 132 1512 200
3631244000322 13926251106 5C-0E-8B-8B-B1-50:CMCC 120.197.40.4 4 0 240 0 200
3631279930342 18212575961 94-71-AC-CD-E6-18:CMCC-EASY 120.196.100.99 iface.qiyi.com 视频网站 15 12 1527 2106 200
3631279950342 13884138413 5C-0E-8B-8C-E8-20:7DaysInn 120.197.40.4 122.72.52.12 20 16 4116 1432 200
3631279930352 13510439658 C4-17-FE-BA-DE-D9:CMCC 120.196.100.99 18 15 1116 954 200
3631279950332 15920133257 5C-0E-8B-C7-BA-20:CMCC 120.197.40.4 sug.so.360.cn 信息安全 20 20 316 296 200
3631279830392 13719199419 68-A1-B7-03-07-B1:CMCC-EASY 120.196.100.82 4 0 240 0 200
3631279840312 13660577991 5C-0E-8B-92-5C-20:CMCC-EASY 120.197.40.4 s19.cnzz.com 站点统计 24 9 660 690 200
3631279730382 15013685858 5C-0E-8B-C7-F7-90:CMCC 120.197.40.4 rank.ie.sogou.com 搜索引擎 28 27 369 338 200
3631279860392 15889002119 E8-99-C4-4E-93-E0:CMCC-EASY 120.196.100.99 www.umeng.com 站点统计 3 3 938 380 200
3631279920332 13560439658 C4-17-FE-BA-DE-D9:CMCC 120.196.100.99 15 9 918 4938 200
3631279860312 13480253104 5C-0E-8B-C7-FC-80:CMCC-EASY 120.197.40.4 3 3 120 1320 200
3631279840302 13602846565 5C-0E-8B-8B-B6-00:CMCC 120.197.40.4 2052.flash2-http.qq.com 综合门户 15 12 198 910 200
3631279950332 13922314466 00-FD-07-A2-EC-BA:CMCC 120.196.100.82 img.qfc.cn 12 12 3008 3720 200
3631279820302 13502468823 5C-0A-5B-6A-0B-D4:CMCC-EASY 120.196.100.99 y0.ifengimg.com 综合门户 57 102 735 11349 400
3631279860322 18320173382 84-25-DB-4F-10-1A:CMCC-EASY 120.196.100.99 input.shouji.sogou.com 搜索引擎 21 18 9531 212 200
3631279900332 13925057413 00-1F-64-E1-E6-9A:CMCC 120.196.100.55 t3.baidu.com 搜索引擎 69 63 11058 4243 200
3631279880322 13760778710 00-FD-07-A4-7B-08:CMCC 120.196.100.82 2 2 120 120 200
3631279850362 13726238888 00-FD-07-A4-72-B8:CMCC 120.196.100.82 i02.c.aliimg.com 24 27 2481 24681 200
3631279930352 13560436666 C4-17-FE-BA-DE-D9:CMCC 120.196.100.99 18 15 1136 94 200
3631279930353 13560436326 C4-17-FE-BA-DE-D9:CMCC 120.196.100.77 lol.qq.com/ 英雄联盟 18 15 1136 94 200
6.输出的文件part-r-00000
13480253104 120 1320 1440
13502468823 735 11349 12084
13510439658 1116 954 2070
13560436326 1136 94 1230
13560436666 1136 94 1230
13560439658 918 4938 5856
13602846565 198 910 1108
13660577991 660 690 1350
13719199419 240 0 240
13726130503 299 681 980
13726238888 2481 24681 27162
13760778710 120 120 240
13822544101 264 0 264
13884138413 4116 1432 5548
13922314466 3008 3720 6728
13925057413 11058 4243 15301
13926251106 240 0 240
13926435656 132 1512 1644
15013685858 369 338 707
15889002119 938 380 1318
15920133257 316 296 612
18212575961 1527 2106 3633
18320173382 9531 212 9743