java操作HDFS------Hadoop学习（3）

1.HDFS中常用到的命令

hadoop fs -ls /
hadoop fs -lsr
hadoop fs -mkdir /user/hadoop
hadoop fs -put a.txt /user/hadoop/
hadoop fs -get /user/hadoop/a.txt /
hadoop fs -cp src dst
hadoop fs -mv src dst
hadoop fs -cat /user/hadoop/a.txt
hadoop fs -rm /user/hadoop/a.txt
hadoop fs -rmr /user/hadoop/a.txt
hadoop fs -text /user/hadoop/a.txt
hadoop fs -copyFromLocal localsrc dst 与hadoop fs -put功能类似。
hadoop fs -moveFromLocal localsrc dst 将本地文件上传到hdfs，同时删除本地文件。

2.Java操作HDFS

public static void main(String[] args) throws IOException, URISyntaxException, InterruptedException {
//文件配置项
FileSystem fs = FileSystem.get(new URI("hdfs://192.168.3.145:9000"), new Configuration(),"root");

//文件夹创建
fs.mkdirs(new Path("/test"));
System.out.println("文件夹创建成功");

//文件上传
FileInputStream in = new FileInputStream(new File("D:/hadoopWorkSpace/HDFSSpace/windows.txt"));
FSDataOutputStream out = fs.create(new Path("/test/windows.txt"));
IOUtils.copyBytes(in, out, 4096, true);
System.out.println("上传文件成功");

//文件夹删除
fs.delete(new Path("/test"), true);
fs.delete(new Path("/test"), true);
System.out.println("文件夹删除成功");

}