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Java program to read a file from HDFS using Hadoop FileSystem API. You need FSDataInputStream to read file. To execute above program in Hadoop environment, you will need to add the directory containing the.class file for the Java program in Hadoop’s classpath. The example commands assume my HDFS data is located in /user/thenson and local files are in the /tmp directory not to be confused with the HDFS /tmp directory. The example data will be loan data set from Kaggle. Using the data set or same file structure isn’t necessary it’s just for a frame of reference. Hadoop fs Commands. Hadoop fs cp – Easiest way to copy data from one source directory to another. Use the. -get [-crc] Copies the file or directory in HDFS identified by src to the local file system path identified by localDest. 13-getmerge Retrieves all files that match the path src in HDFS, and copies them to a single, merged file in the local file system identified by.

get / getmerge / copyToLocal / moveToLocal. getはHDFS上のファイルをローカルにコピーする。 // HDFS上のfoo.txtというファイルをローカルにbar.txtという名前でコピー $ hadoop fs -get foo.txt bar.txt // 既にファイルがあると怒られる（copyToLocalも同じ挙動） $ hadoop fs -get foo.txt bar.txt. We can use the org.apache.hadoop.fs.FileStatus class to get the file metadata like Block size, File permissions & Ownership, replication factor. Can we get the same metadata using org.apache.hadoop.fs.FileSystem class. If yes whats the difference between FileSystem and.