hdfs例子之读写MapFile

package mytest;import java.io.IOException;import java.net.URI;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.io.IOUtils;import org.apache.hadoop.io.MapFile;import org.apache.hadoop.io.Text;public class MyMapFileTest {private static void write() throws IOException {Configuration conf = new Configuration();URI uri = URI.create("file:///home/yunpeng/mapFile.map");FileSystem fs = FileSystem.get(uri, conf);MapFile.Writer writer = null;writer = new MapFile.Writer(conf, fs, uri.getPath(), Text.class, Text.class);//通过writer向文档中写入记录  writer.append(new Text("key"), new Text("value"));IOUtils.closeStream(writer);//关闭write流  }private static void read() throws IOException {Configuration conf = new Configuration();URI uri = URI.create("file:///home/yunpeng/mapFile.map");FileSystem fs = FileSystem.get(uri, conf);MapFile.Reader reader = null;reader = new MapFile.Reader(fs, uri.getPath(), conf);//通过writer向文档中写入记录  Text key = new Text();Text value = new Text();while (reader.next(key, value)) {System.out.println(key);System.out.println(value);}IOUtils.closeStream(reader);//关闭write流  }public static void main(String[] args) throws IOException {read();}}

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