自定义output文件，并指定输出的文件路径以及文件名

需求：有如下文件，需要将itstar输出到一个文件，其他的输出到另一个文件，并自定义输出文件路径与文件名

1：定义FilterMap类

package 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 FilterMap extends Mapper<LongWritable, Text, Text, NullWritable> {
    Text k = new Text();
    @Override
    protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
        //获取一行
        String line = value.toString();
        k.set(line);
        //写出
        context.write(k, NullWritable.get());
    }
}

2：定义FilterReducer类

package 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 FilterReducer extends Reducer<Text, NullWritable, Text, NullWritable> {
    @Override
    protected void reduce(Text key, Iterable<NullWritable> values, Context context)
                                          throws IOException, InterruptedException {
        String line = key.toString();
        line = line + "\r\n";
        context.write(new Text(line), NullWritable.get());
    }
}

3：定义了FilterlogRecordWriter类

package OutputFormat;
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;
import java.io.IOException;

public class FilterlogRecordWriter extends RecordWriter<Text, NullWritable> {    
    FSDataOutputStream itstarOut = null;
    FSDataOutputStream otherOut = null;

    /**
     * 数据的输出环节
     * @param job 用于获取配置信息，从而得到从而得到fs
     */
    public FilterlogRecordWriter(TaskAttemptContext job) {
        //数据的输出
        try {
            FileSystem fs = FileSystem.get(job.getConfiguration());

            Path itstarPath = new Path("E:\\bigdata_code\\outputformat\\out\\itstar.log");
            Path otherPath = new Path("E:\\bigdata_code\\outputformat\\out\\other.log");

            itstarOut = fs.create(itstarPath);
            otherOut = fs.create(otherPath);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    @Override
    public void write(Text text, NullWritable nullWritable) throws IOException, InterruptedException {
        if(text.toString().contains("itstar")){
            itstarOut.write(text.toString().getBytes());
        }else {
            otherOut.write(text.toString().getBytes());
        }
    }
    @Override
    public void close(TaskAttemptContext taskAttemptContext) throws IOException, InterruptedException {
        if(itstarOut != null){
            itstarOut.close();
        }
        if(otherOut != null){
            otherOut.close();
        }
    }
}

4：定义了FilterlogOutputFormat类

package 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 FilterlogOutputFormat extends FileOutputFormat<Text, NullWritable> {

    public RecordWriter<Text, NullWritable> getRecordWriter(TaskAttemptContext job)
                                        throws IOException, InterruptedException {

        return new FilterlogRecordWriter(job);
    }
}

5：定义了FilterDriver类

package 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;
import java.io.IOException;

public class FilterDriver {
    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
        args = new String[] {"E:\\bigdata_code\\outputformat\\outputformat.txt",
                             "E:\\bigdata_code\\outputformat\\out"};

        Configuration conf = new Configuration();
        Job job = Job.getInstance(conf);
        job.setJarByClass(FilterDriver.class);

        job.setMapperClass(FilterMap.class);
        job.setMapOutputKeyClass(Text.class);
        job.setMapOutputValueClass(NullWritable.class);

        job.setReducerClass(FilterReducer.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
        job.setOutputFormatClass(FilterlogOutputFormat.class);

        FileInputFormat.setInputPaths(job, new Path(args[0]));
        // 虽然自定义了outputformat，但是因为OutputFormat继承自fileoutputformat，
        // 而fileoutputformat要输出一个SUCCESS文件，所以这里还要指定一个输出目录
        FileOutputFormat.setOutputPath(job, new Path(args[1]));

        job.waitForCompletion(true);
    }
}
输出结果：