Hadoop HDFS copyMergeFromLocal

在谈到HDFS优化中，其中HDFS擅长处理大文件，而对于小文件常用的优化策略有压缩合并。在此列举小文件合并工具类供参考。

/**
* Get all the files in the directories that match the source file pattern
* and merge and sort them to only one file on HDFS is kept.
* 
* Also adds a string between the files (useful for adding 

* to a text file)
* @param srcf: a file pattern specifying source files
* @param dstf: a destination local file/directory
* @param endline: if an end of line character is added to a text file 
* @exception: IOException 
*/
public static void copyMergeFromLocal(String srcf, Path dst, boolean endline)
            throws IOException {
        Configuration conf = new Configuration();
        Path srcPath = new Path(srcf);
        FileSystem dstFs = srcPath.getFileSystem(conf);
        FileSystem srcFs = FileSystem.getLocal(conf);
        Path[] srcs = FileUtil.stat2Paths(srcFs.globStatus(srcPath), srcPath);
        for (Path src : srcs) {
            FileUtil.copyMerge(srcFs, src,
                    dstFs, dst, false, conf,
                    endline ? "
" : null);
        }
    }
void copyMergeFromLocal(String srcf, Path dst) throws IOException {
    copyMergeFromLocal(srcf, dst, false);
  }

在HDFS文件上传时，可以设置过滤条件，使小文件自动合并。