package com.uplooking.bigdata.mr.writablez.sequecefile; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.io.SequenceFile; import org.apache.hadoop.io.SequenceFile.Reader; import org.apache.hadoop.io.SequenceFile.Reader.Option; import org.apache.hadoop.io.Text; import java.io.*; /** * 将一个SequenceFile的文件转变成为一个普通的文本文件 */ public class SequenceFileReadOps { public static void main(String[] args) throws Exception { if(args == null || args.length < 2) { System.err.println("Parameter Errors ! Usage: <inputpath outputpath>"); System.exit(-1); } String inputpath = args[0]; // Path outputpath = new Path(args[1]); String outputpath = args[1]; Configuration conf = new Configuration(); Option inputOps = Reader.file(new Path(inputpath)); Option[] opts = new Option[]{inputOps}; Reader reader = new SequenceFile.Reader(conf, opts); Text key = new Text(); BufferedWriter bw = new BufferedWriter(new FileWriter(outputpath)); while(reader.next(key, NullWritable.get())) {//将数据写入到key里面了 String line = key.toString(); bw.write(line); bw.newLine(); } bw.close(); reader.close(); } }
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