Hadoop案例（五）过滤日志及自定义日志输出路径（自定义OutputFormat)

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过滤日志及自定义日志输出路径（自定义OutputFormat）

1.需求分析

过滤输入的log日志中是否包含xyg

（1）包含xyg的网站输出到e:/xyg.log

（2）不包含xyg的网站输出到e:/other.log

2.数据准备

http://www.baidu.com
http://www.google.com
http://cn.bing.com
http://www.xyg.com
http://www.sohu.com
http://www.sina.com
http://www.sin2a.com
http://www.sin2desa.com
http://www.sindsafa.com

log.txt

输出预期：

http://www.xyg.com

xyg.txt

http://cn.bing.com
http://www.baidu.com
http://www.google.com
http://www.sin2a.com
http://www.sin2desa.com
http://www.sina.com
http://www.sindsafa.com
http://www.sohu.com

other.txt

3.代码实现

（1）自定义一个outputformat

package com.xyg.mapreduce.outputformat;

import java.io.IOException;
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;public class FilterOutputFormat extends FileOutputFormat<Text, NullWritable>{@Overridepublic RecordWriter<Text, NullWritable> getRecordWriter(TaskAttemptContext job) throws IOException, InterruptedException {// 创建一个RecordWriterreturn new FilterRecordWriter(job);}
}

（2）具体的写数据RecordWriter

package com.xyg.mapreduce.outputformat;

import java.io.IOException;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;public class FilterRecordWriter extends RecordWriter<Text, NullWritable> {FSDataOutputStream atguiguOut = null;FSDataOutputStream otherOut = null;public FilterRecordWriter(TaskAttemptContext job) {// 1 获取文件系统
        FileSystem fs;try {fs = FileSystem.get(job.getConfiguration());// 2 创建输出文件路径Path atguiguPath = new Path("e:/xyg.log");Path otherPath = new Path("e:/other.log");// 3 创建输出流atguiguOut = fs.create(atguiguPath);otherOut = fs.create(otherPath);} catch (IOException e) {e.printStackTrace();}}@Overridepublic void write(Text key, NullWritable value) throws IOException, InterruptedException {// 判断是否包含“xyg”输出到不同文件if (key.toString().contains("xyg")) {atguiguOut.write(key.toString().getBytes());} else {otherOut.write(key.toString().getBytes());}}@Overridepublic void close(TaskAttemptContext context) throws IOException, InterruptedException {// 关闭资源if (atguiguOut != null) {atguiguOut.close();}if (otherOut != null) {otherOut.close();}}
}

（3）编写FilterMapper

package com.xyg.mapreduce.outputformat;

import java.io.IOException;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;public class FilterMapper extends Mapper<LongWritable, Text, Text, NullWritable>{Text k = new Text();@Overrideprotected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
// 1 获取一行String line = value.toString();k.set(line);// 3 写出context.write(k, NullWritable.get());}
}

（4）编写FilterReducer

package com.xyg.mapreduce.outputformat;

import java.io.IOException;
import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Reducer;public class FilterReducer extends Reducer<Text, NullWritable, Text, NullWritable> {@Overrideprotected void reduce(Text key, Iterable<NullWritable> values, Context context) throws IOException, InterruptedException {String k = key.toString();k = k + "\r\n";context.write(new Text(k), NullWritable.get());}
}

（5）编写FilterDriver

package com.xyg.mapreduce.outputformat;

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;public class FilterDriver {public static void main(String[] args) throws Exception {args = new String[] { "e:/inputoutputformat", "e:/output2" };Configuration conf = new Configuration();Job job = Job.getInstance(conf);job.setJarByClass(FilterDriver.class);job.setMapperClass(FilterMapper.class);job.setReducerClass(FilterReducer.class);job.setMapOutputKeyClass(Text.class);job.setMapOutputValueClass(NullWritable.class);job.setOutputKeyClass(Text.class);job.setOutputValueClass(NullWritable.class);// 要将自定义的输出格式组件设置到job中job.setOutputFormatClass(FilterOutputFormat.class);FileInputFormat.setInputPaths(job, new Path(args[0]));// 虽然我们自定义了outputformat，但是因为我们的outputformat继承自fileoutputformat// 而fileoutputformat要输出一个_SUCCESS文件，所以，在这还得指定一个输出目录FileOutputFormat.setOutputPath(job, new Path(args[1]));boolean result = job.waitForCompletion(true);System.exit(result ? 0 : 1);}
}