Hadoop join 关联提升版 开发代码调整解决 reduce时候 OOM问题

1、数据文件

[root@master IMFdatatest]#cat members.txt
1       Spark   1
2       Hadoop  1
3       flink   3
4       Kafka   1
5       Tachyon 2
[root@master IMFdatatest]#cat address.txt
1       America
2       China
3       Germa

2、上次文件到hdfs

 

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代码分析

1、自定义MemberKey hadoop如何定义key体现开发人员的水准
private int keyID
private boolean flag
compareTo方法
hashCode方法，就以keyID作为hashCode值

2、自定义类Member_Information，包含成员ID 成员名字    地址

ID  地址
 String memberNo
 String memberName
 String addresNo
 String addressName

3、自定义GroupComparator
定义组的compare方法

4、map

读入成员和地址文件，如每行分割的数据为2列，是地址文件，读入类

Member_Information的地址ID和地址，KEY值读入MemberKey， 地址ID，及

flag=true；map输出MemberKey、Member_Information；

读入成员和地址文件，如每行分割的数据不为2列，是成员文件，读入类

Member_Information的成员ID和成员名称和地址编号，KEY值读入

MemberKey， 地址ID，及flag=false；map输出MemberKey、

Member_Information

5、值的比大小。
在MemberKey中比大小，keyID 就是地址ID和flag都相等，则两个

MemberKey相等；如果地址ID一样，如果flag为true，则这个MemberKey就

小，对应的是地址文件的情况，因此就地址文件就排到了第一个元素；如

果地址ID不一样，就按地址ID比大小。

 public int compareTo(MemberKey member) {
  if (this.keyID == member.keyID){
   if(this.flag == member.flag){
    return 0;
   } else {
    return this.flag? -1:1;
   }
  } else {
   return this.keyID  - member.keyID > 0? 1

:-1;
  }
 }
 

分组比大小：
分组时只按KeyID()比大小，地址ID大的就大。就按地址ID进行了分组，这样地址ID相同的地址文件和成员文件中的值就组合在一起了。

class GroupComparator extends WritableComparator{

 public GroupComparator() {
  super(MemberKey.class, true);
 }

 @Override
 public int compare(WritableComparable a,

WritableComparable b) {
  MemberKey x = (MemberKey)a;
  MemberKey y = (MemberKey)b;
  
  System.out.println("GroupComparator has been

invoked!!!");
  
  if(x.getKeyID() == y.getKeyID()){
   return 0;
  } else {
   return x.getKeyID() > y.getKeyID()? 1 :

-1;
  }
  
 }
5、reduce
地址ID相同的地址文件和成员文件中的值就组合在一起，这样地址ID一样，如果flag为true，则这个MemberKey就

小，对应的是地址文件的情况，因此就地址文件就排到了第一个元素，第一个元素我们不输出，仅仅输出之后的成员文件的值，

输出 Member_Information

就避免了之前的例子join建立一个list，不停给list内存中放数据而产生的OOM溢出情况，完成了性能优化

 

 

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

 

 

3、运行结果

[root@master IMFdatatest]#hadoop dfs -cat /library/outputJoinimprove/part-r-00000
DEPRECATED: Use of this script to execute hdfs command is deprecated.
Instead use the hdfs command for it.

16/02/20 06:53:39 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
4 Kafka America
2 Hadoop America
1 Spark America
5 Tachyon China
3 flink Germa

 

4、截图

 

5、源代码

package com.dtspark.hadoop.hellomapreduce;

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

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableComparator;
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;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;

public class JoinImproved {
  public static class DataMapper
     extends Mapper{

 public void map(LongWritable key, Text value, Context context
                   ) throws IOException, InterruptedException {
 
    System.out.println("Map Methond Invoked!!!");
  
    String data = value.toString();
    String[] dataSplited = data.split("\t");
   
    if(dataSplited.length == 2){
     Member_Information member = new Member_Information();
     member.setAddresNo(dataSplited[0]);
     member.setAddressName(dataSplited[1]);
//     member.setFlag(0);
    
     MemberKey memberKey = new MemberKey();
     memberKey.setKeyID(Integer.valueOf(dataSplited[0]));
     memberKey.setFlag(true);
    
     context.write(memberKey, member);
    } else {
     Member_Information member = new Member_Information();
     member.setMemberNo(dataSplited[0]);
     member.setMemberName(dataSplited[1]);
     member.setAddresNo(dataSplited[2]);
//     member.setFlag(1);
    
     MemberKey memberKey = new MemberKey();
     memberKey.setKeyID(Integer.valueOf(dataSplited[2]));
     memberKey.setFlag(false);
    
     context.write(memberKey, member);
    }
   
   
            
    }

 

  }

public static class DataReducer
     extends Reducer {
 
 public void reduce(MemberKey key, Iterable values,
                      Context context
                      ) throws IOException, InterruptedException {
    System.out.println("Reduce Methond Invoked!!!" );
   
    Member_Information member = new Member_Information();
    int counter = 0;
    for(Member_Information item : values){
     if(0 == counter){
      member = new Member_Information(item);
     } else {
      Member_Information mem = new Member_Information(item);
      mem.setAddressName(member.getAddressName());
     
      context.write(NullWritable.get(), new Text(mem.toString()));
     }
    
     counter++;
    }
  
   }
  
}

public static void main(String[] args) throws Exception {
 
 
 
  Configuration conf = new Configuration();
  String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
  if (otherArgs.length < 2) {
    System.err.println("Usage: JoinImproved [...] ");
    System.exit(2);
  }

 
 
  Job job = Job.getInstance(conf, "JoinImproved");
  job.setJarByClass(JoinImproved.class);
 
  job.setMapperClass(DataMapper.class);
  job.setReducerClass(DataReducer.class);
  job.setMapOutputKeyClass(MemberKey.class);
  job.setMapOutputValueClass(Member_Information.class);
  job.setOutputKeyClass(NullWritable.class);
  job.setOutputValueClass(Text.class);
 
 
 
  job.setGroupingComparatorClass(GroupComparator.class);
 
  for (int i = 0; i < otherArgs.length - 1; ++i) {
    FileInputFormat.addInputPath(job, new Path(otherArgs[i]));
  }
  FileOutputFormat.setOutputPath(job,
    new Path(otherArgs[otherArgs.length - 1]));
  System.exit(job.waitForCompletion(true) ? 0 : 1);
}

}

class GroupComparator extends WritableComparator{

 public GroupComparator() {
  super(MemberKey.class, true);
 }

 @Override
 public int compare(WritableComparable a, WritableComparable b) {
  MemberKey x = (MemberKey)a;
  MemberKey y = (MemberKey)b;
  
  System.out.println("GroupComparator has been invoked!!!");
  
  if(x.getKeyID() == y.getKeyID()){
   return 0;
  } else {
   return x.getKeyID() > y.getKeyID()? 1 : -1;
  }
  
 }
 
 
 
}

class MemberKey implements WritableComparable{
 private int keyID;
 private boolean flag;
 
 
 public MemberKey(){}
 
 @Override
 public int hashCode() {
  return this.keyID;
 }

 

 public MemberKey(int keyID, boolean flag) {
  this.keyID = keyID;
  this.flag = flag;
 }

 public int getKeyID() {
  return keyID;
 }

 public void setKeyID(int keyID) {
  this.keyID = keyID;
 }

 public boolean isFlag() {
  return flag;
 }

 public void setFlag(boolean flag) {
  this.flag = flag;
 }

 
 
 

 @Override
 public void readFields(DataInput input) throws IOException {
  this.keyID = input.readInt();
  this.flag = input.readBoolean();
  
 }

 @Override
 public void write(DataOutput output) throws IOException {
  output.writeInt(this.keyID);
  output.writeBoolean(this.flag);
  
 }

 @Override
 public int compareTo(MemberKey member) {
  if (this.keyID == member.keyID){
   if(this.flag == member.flag){
    return 0;
   } else {
    return this.flag? -1:1;
   }
  } else {
   return this.keyID  - member.keyID > 0? 1 :-1;
  }
 }
 
}

class Member_Information implements WritableComparable{
 private String memberNo = "";
 private String memberName = "";
 private String addresNo = "";
 private String addressName = "";
 
 public Member_Information(){}
 
 

 public Member_Information(String memberNo, String memberName, String addresNo, String addressName) {
  super();
  this.memberNo = memberNo;
  this.memberName = memberName;
  this.addresNo = addresNo;
  this.addressName = addressName;
 }
 
 public Member_Information(Member_Information info){
  this.memberNo = info.memberNo;
  this.memberName = info.memberName;
  this.addresNo = info.addresNo;
  this.addressName = info.addressName;
 }
 @Override
 public void readFields(DataInput input) throws IOException {
  this.memberNo = input.readUTF();
  this.memberName = input.readUTF();
  this.addresNo = input.readUTF();
  this.addressName = input.readUTF();
  
 }

 @Override
 public void write(DataOutput output) throws IOException {
  output.writeUTF(this.memberNo);
  output.writeUTF(this.memberName);
  output.writeUTF(this.addresNo);
  output.writeUTF(this.addressName);
  
  
 }

 

 public String getMemberNo() {
  return memberNo;
 }

 

 public void setMemberNo(String memberNo) {
  this.memberNo = memberNo;
 }

 

 public String getMemberName() {
  return memberName;
 }

 

 public void setMemberName(String memberName) {
  this.memberName = memberName;
 }

 

 public String getAddresNo() {
  return addresNo;
 }

 

 public void setAddresNo(String addresNo) {
  this.addresNo = addresNo;
 }

 

 public String getAddressName() {
  return addressName;
 }

 

 public void setAddressName(String addressName) {
  this.addressName = addressName;
 }

 

 

 
 @Override
 public String toString() {
  
  return this.memberNo + " " + this.memberName + " " + this.addressName;
 }

 

 @Override
 public int compareTo(Member_Information o) {
  // TODO Auto-generated method stub
  return 0;
 }
  

 

}