HADOOP MAPREDUCE(10):OutputFormat数据输出
1 OutputFormat接口实现类
2 自定义OutputFormat
3 自定义OutputFormat案例实操
1.需求
过滤输入的log日志,包含atguigu的网站输出到e:/atguigu.log,不包含atguigu的网站输出到e:/other.log。
(1)输入数据
(2)期望输出数据
2.需求分析
3.案例实操
(1)编写FilterMapper类
package com.atguigu.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>{ @Override protected void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException { // 写出 context.write(value, NullWritable.get()); } }
(2)编写FilterReducer类
package com.atguigu.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> { Text k = new Text(); @Override protected void reduce(Text key, Iterable<NullWritable> values, Context context) throws IOException, InterruptedException { // 1 获取一行 String line = key.toString(); // 2 拼接 line = line + "\r\n"; // 3 设置key k.set(line); // 4 输出 context.write(k, NullWritable.get()); } }
(3)自定义一个OutputFormat类
package com.atguigu.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>{ @Override public RecordWriter<Text, NullWritable> getRecordWriter(TaskAttemptContext job) throws IOException, InterruptedException { // 创建一个RecordWriter return new FilterRecordWriter(job); } }
(4)编写RecordWriter类
package com.atguigu.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:/atguigu.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(); } } @Override public void write(Text key, NullWritable value) throws IOException, InterruptedException { // 判断是否包含“atguigu”输出到不同文件 if (key.toString().contains("atguigu")) { atguiguOut.write(key.toString().getBytes()); } else { otherOut.write(key.toString().getBytes()); } } @Override public void close(TaskAttemptContext context) throws IOException, InterruptedException { // 关闭资源 IOUtils.closeStream(atguiguOut); IOUtils.closeStream(otherOut); } }
(5)编写FilterDriver类
package com.atguigu.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 { // 输入输出路径需要根据自己电脑上实际的输入输出路径设置 args = new String[] { "e:/input/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); } }
本文来自博客园,作者:秋华,转载请注明原文链接:https://www.cnblogs.com/qiu-hua/p/13341090.html