写的例子：
package mytest.mapreduce;import java.io.IOException;import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Text;public class MySequenceTester {private static final String data[] = {"One, two, buckle my shoe","Three, four, shut the door","Five, six, pick up sticks","Seven, eight, lay them straight","Nine, ten, a big fat hen"};public static void main(String[] args) throws IOException {Configuration conf = new Configuration();FileSystem fs = FileSystem.get(conf);Path path = new Path("/duitang/data/test/client-request.log.seq");IntWritable key = new IntWritable();Text value = new Text();SequenceFile.Writer writer = SequenceFile.createWriter(fs, conf, path, key.getClass(), value.getClass());try {for (int i = 0; i < 100; i++) {key.set(100 - i);value.set(data[i % data.length]);System.out.printf("[%s]\t%s\t%s\n", writer.getLength(), key, value);writer.append(key, value);}} finally {IOUtils.closeStream(writer);}}
}