HDFS常用命令

创建目录 -mkdir

hadoop fs -mkdir -p /aaa/bbb

从本地剪切文件到hdfs -moveFromLocal

hadoop fs -moveFromLocal ./file.txt /aaa/

从本地复制文件到hdfs -copyFromLocal

hadoop fs -copyFromLocal ./file.txt /aaa/

从hdfs剪切文件到本地 -moveToLocal

hadoop fs -moveToLocal /aaa/file.txt /folder/

从hdfs复制文件到本地 -copyToLocal

hadoop fs -copyToLocal /aaa/file.txt /folder/

删除文件或文件夹 -rm

hadoop fs -rm -r /aaa/bbb/

HDFS读取文件代码

public class HDFSFileReader {
    public static void main(String[] args) {
        try {
            Configuration conf = new Configuration();
            FileSystem fs = FileSystem.get(conf);
            Path filename = new Path("hdfs://localhost:9000/user/hadoop/test.txt");
            FSDataInputStream is = fs.open(filename);
            BufferedReader d = new BufferedReader(new InputStreamReader(is));
            String content = d.readLine();
            System.out.println(content);
            d.close();
            fs.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}