OutputFormat---自定义输出方式

提示：扫一扫查出行
【扫一扫了解最新限行尾号】
复制提示

简介

可以自定义输出的格式和文件，例如包含某字段的输出到一个指定文件，不包含某字段的输出到另一个文件。

案例

数据

www.nevesettle.com
www.baidu.com
www.qq.com
www.mi.com
www.jd.com
www.std.com


Mapper

package com.neve.outputformat;import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;import java.io.IOException;public class LogMapper extends Mapper<LongWritable, Text,Text, NullWritable> { @Override
protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { context.write(value,NullWritable.get());
}
}

Reducer

package com.neve.outputformat;import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;import java.io.IOException;public class LogReducer extends Reducer<Text, NullWritable,Text,NullWritable> { @Override
protected void reduce(Text key, Iterable<NullWritable> values, Context context) throws IOException, InterruptedException { for (NullWritable value : values) {
context.write(key,value);
} }
}

Driver

package com.neve.outputformat;import com.neve.phone.FlowBean;
import com.neve.phone.FlowMapper;
import com.neve.phone.FlowReducer;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
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;import java.io.IOException;public class LogDriver { public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException { //1.创建配置
Configuration configuration = new Configuration();
//2.创建job
Job job = Job.getInstance(configuration);
//3.关联驱动类
job.setJarByClass(LogDriver.class);
//4.关联mapper和reducer类
job.setMapperClass(LogMapper.class);
job.setReducerClass(LogReducer.class);
//5.设置mapper的输出值和value
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(NullWritable.class);
//6.设置最终的输出值和value
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(NullWritable.class);
//7.设置输入输出路径
FileInputFormat.setInputPaths(job,new Path("F:\\Workplace\\IDEA_Workplace\\hadoopStudy2\\outputformatinput"));
FileOutputFormat.setOutputPath(job,new Path("F:\\Workplace\\IDEA_Workplace\\hadoopStudy2\\outputformatoutput"));
//设置自定义的format类
job.setOutputFormatClass(LogOutputFormat.class);
//8.提交job
job.waitForCompletion(true); }
}

LogOutputFormat

package com.neve.outputformat;import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;import java.io.IOException;public class LogOutputFormat extends FileOutputFormat<Text, NullWritable> { public RecordWriter<Text, NullWritable> getRecordWriter(TaskAttemptContext job) throws IOException, InterruptedException {
LogRecordWriter logw = new LogRecordWriter(job);
return logw;
}
}

LogRecordWriter

package com.neve.outputformat;import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;import java.io.IOException;public class LogRecordWriter extends RecordWriter<Text, NullWritable> { //定义输出路径
private String nelog = "F:\\nelog.log";
private String otherlog = "F:\\otherlog.log"; private FileSystem fs ;
private FSDataOutputStream neos;
private FSDataOutputStream otheros; public LogRecordWriter(TaskAttemptContext job) throws IOException {
//获取文件系统对象
fs = FileSystem.get(job.getConfiguration());
neos = fs.create(new Path(nelog));
otheros = fs.create(new Path(otherlog));
} public void write(Text key, NullWritable value) throws IOException, InterruptedException {
String string = key.toString();
if (string.contains("neve")){
neos.writeBytes(string + "\r");
}else {
otheros.writeBytes(string + "\r");
}
} public void close(TaskAttemptContext context) throws IOException, InterruptedException {
IOUtils.closeStream(neos);
IOUtils.closeStream(otheros);
}
}