//这3个程序需要什么包???如何将这三个程序合并为一个程序??如何在eclipse中使用这个3程序进行mapreduce??
请帮我成功运行这个程序
os:linux
面临异常:
- 类型的TryParseInt(String)方法未定义MaxPYear.MaxPubYearReducer
2.中的方法setInputFormatClass(Class)Job类型不适用于参数(类别)
映射器代码:
public static class MaxPubYearMapper extends Mapper<LongWritable , Text, IntWritable,Text>
{
public void map(LongWritable key, Text value , Context context)
throws IOException, InterruptedException
{
String delim = "t";
Text valtosend = new Text();
String tokens[] = value.toString().split(delim);
if (tokens.length == 2)
{
valtosend.set(tokens[0] + ";"+ tokens[1]);
context.write(new IntWritable(1), valtosend);
}
}
}
减速器代码:
public static class MaxPubYearReducer extends Reducer<IntWritable ,Text, Text, IntWritable>
{
public void reduce(IntWritable key, Iterable<Text> values , Context context) throws IOException, InterruptedException
{
int maxiValue = Integer.MIN_VALUE;
String maxiYear = "";
for(Text value:values) {
String token[] = value.toString().split(";");
if(token.length == 2 && TryParseInt(token[1]).intValue()> maxiValue)
{
maxiValue = TryParseInt(token[1]);
maxiYear = token[0];
}
}
context.write(new Text(maxiYear), new IntWritable(maxiValue));
}
}
驱动程序代码:
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = new Job(conf , "Frequency`enter code here`");
job.setJarByClass(MaxPubYear.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
job.setMapperClass(FrequencyMapper.class);
job.setCombinerClass(FrequencyReducer.class);
job.setReducerClass(FrequencyReducer.class);
job.setOutputFormatClass(TextOutputFormat.class);
job.setInputFormatClass(TextInputFormat.class);
FileInputFormat.addInputPath(job,new Path(args[0]));
FileOutputFormat.setOutputPath(job,new Path(args[1]+ "_temp"));
int exitCode = job.waitForCompletion(true)?0:1;
if (exitCode == 0 )
{
Job SecondJob = new Job(conf, "Maximum Publication year");
SecondJob.setJarByClass(MaxPubYear.class);
SecondJob.setOutputKeyClass(Text.class);
SecondJob.setOutputValueClass(IntWritable.class);
SecondJob.setMapOutputKeyClass(IntWritable.class);
SecondJob.setMapOutputValueClass(Text.class);
SecondJob.setMapperClass(MaxPubYearMapper.class);
SecondJob.setReducerClass(MaxPubYearReducer.class);
FileInputFormat.addInputPath(SecondJob,new Path(args[1]+ "_temp"));
FileOutputFormat.setOutputPath(SecondJob,new Path(args[1]));
System.exit(SecondJob.waitForCompletion(true)?0:1);
}
}
将它们一起写在一个类中
所需的包裹有:
package org.myorg;
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
import java.io.DataInput;
import java.io.DataOutput;
这里可能有一些额外的东西,因为我从代码中复制了它们。
package org.myorg;
import java.util.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.*;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
public class <your classname as well as filename> {
public static class MaxPubYearMapper extends Mapper<LongWritable , Text, IntWritable,Text>
{
public void map(LongWritable key, Text value , Context context)
throws IOException, InterruptedException
{
String delim = "t";
Text valtosend = new Text();
String tokens[] = value.toString().split(delim);
if (tokens.length == 2)
{
valtosend.set(tokens[0] + ";"+ tokens[1]);
context.write(new IntWritable(1), valtosend);
}
}
}
public static class MaxPubYearReducer extends Reducer<IntWritable ,Text, Text, IntWritable>
{
public void reduce(IntWritable key, Iterable<Text> values , Context context) throws IOException, InterruptedException
{
int maxiValue = Integer.MIN_VALUE;
String maxiYear = "";
for(Text value:values) {
String token[] = value.toString().split(";");
if(token.length == 2 && TryParseInt(token[1]).intValue()> maxiValue)
{
maxiValue = TryParseInt(token[1]);
maxiYear = token[0];
}
}
context.write(new Text(maxiYear), new IntWritable(maxiValue));
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
Job job = new Job(conf , "Frequency`enter code here`");
job.setJarByClass(MaxPubYear.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
job.setMapperClass(FrequencyMapper.class);
job.setCombinerClass(FrequencyReducer.class);
job.setReducerClass(FrequencyReducer.class);
job.setOutputFormatClass(TextOutputFormat.class);
job.setInputFormatClass(TextInputFormat.class);
FileInputFormat.addInputPath(job,new Path(args[0]));
FileOutputFormat.setOutputPath(job,new Path(args[1]+ "_temp"));
int exitCode = job.waitForCompletion(true)?0:1;
if (exitCode == 0 )
{
Job SecondJob = new Job(conf, "Maximum Publication year");
SecondJob.setJarByClass(MaxPubYear.class);
SecondJob.setOutputKeyClass(Text.class);
SecondJob.setOutputValueClass(IntWritable.class);
SecondJob.setMapOutputKeyClass(IntWritable.class);
SecondJob.setMapOutputValueClass(Text.class);
SecondJob.setMapperClass(MaxPubYearMapper.class);
SecondJob.setReducerClass(MaxPubYearReducer.class);
FileInputFormat.addInputPath(SecondJob,new Path(args[1]+ "_temp"));
FileOutputFormat.setOutputPath(SecondJob,new Path(args[1]));
System.exit(SecondJob.waitForCompletion(true)?0:1);
}
}
}