Hadoop下将大量小文件生成一个sequenceFile文件

1）遇到的问题，因为是在集群上运行，代码中String seqFsUrl = "hdfs://localhost:9000/user/mjiang/target-seq/sdfgz.seq";的localhost错误，

于是老是出现连接不上的问题，（Retrying connect to server: localhost/127.0.0.1:8020. Already tried 0 time(s).）

所以运行程序时出现连接不上Hadoop的问题时，考虑是不是程序写错了。

2）sequenceFile中虽然是按文件名（或其他任何值）为键，文件内容为值来存储的。但用SequenceFileAsTextInputFormat来读取时，键值还是会被读到文件的第一行

没分析源码，不清楚原因

3）sequenceFile可以处理.gz文件（没有实验出不行，按说.gz文件是不可以分块存储的？？？逻辑上还是一个）

 import java.io.BufferedInputStream;
import java.io.FileInputStream;
 import java.io.IOException;
import java.io.InputStream;
 import java.io.File;
import java.net.URI;

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.NullWritable;
 import org.apache.Hadoop.io.SequenceFile;
import org.apache.Hadoop.io.Text;

public class sequeneceFile{

    public static void main(String[] args) throws IOException {

        //String seqFsUrl = "hdfs://localhost:9000/user/mjiang/target-seq/sdfgz.seq";
         String seqFsUrl = "user/mjiang/target-seq/sdfgz.seq";

         Configuration conf = new Configuration();
        //conf.set("fs.default.name", "hdfs://venus:9000");
         //conf.set("Hadoop.job.user", "mjiang");
        //conf.set("mapred.job.tracker", "venus:9001");

        FileSystem fs = FileSystem.get(URI.create(seqFsUrl),conf);

        Path seqPath = new Path(seqFsUrl);

        //Text key = new Text();

        Text value = new Text();

        String filesPath = "/home/mjiang/java/eclipse/Hadoop/sequenceFile/data/sdfgz/";

        File gzFilesDir = new File(filesPath);

        String[] gzFiles = gzFilesDir.list();

        int filesLen=gzFiles.length;

        SequenceFile.Writer writer = null;

        try {//返回一个SequenceFile.Writer实例 需要数据流和path对象 将数据写入了path对象


             writer = SequenceFile.createWriter(fs, conf, seqPath,NullWritable.class, value.getClass());

             //for (int i=0;i<2;i++){

             while (filesLen>0){

                 File gzFile = new File(filesPath+gzFiles[filesLen-1]);

                 InputStream in = new BufferedInputStream(new FileInputStream(gzFile));

                 long len = gzFile.length();

                 byte[] buff = new byte[(int)len];

                 if ((len = in.read(buff))!= -1) {

                     value.set(buff);

                     writer.append(NullWritable.get(), value);//将每条记录追加到SequenceFile.Writer实例的末尾

                 }

                 //process

                 System.out.println(gzFiles[filesLen-1]);

                 //key.clear();

                 value.clear();

                 IOUtils.closeStream(in);

                 filesLen--;//!!

             }
            //filesLen = 2; }
         } finally {

             IOUtils.closeStream(writer);

         }
    }
 }