HDFS中Java的API使用测试

import java.io.IOException;
import java.util.Arrays;
import java.util.Date;
import java.util.Scanner;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hdfs.protocol.DatanodeInfo;

class TestHDFSFile {

	// 在hdfs上创建目录
	public void CreateFilePath(String hdfspath) throws IOException {
		Configuration conf = new Configuration();
		FileSystem hdfs = FileSystem.get(conf);
		// System.out.println("Upload to " + conf.get("fs.default.name"));
		if (hdfs.exists(new Path(hdfspath))) {
			System.out.println("文件目录已存在");
		} else {
			hdfs.mkdirs(new Path(hdfspath));
		}

		// 列出该目录下的所有文件，以便查看
		Path parentpath = new Path(hdfspath);
		HdfsFileList(parentpath.getParent());

	}

	// 查看某目录下的文件列表
	public void HdfsFileList(Path hdfspath) throws IOException {
		Configuration conf = new Configuration();
		FileSystem hdfs = FileSystem.get(conf);
		// System.out.println("Upload to " + conf.get("fs.default.name"));
		FileStatus files[] = hdfs.listStatus(hdfspath);
		if (files.length == 0) {
			System.out.println("该目录下没有任何文件");
		} else {
			for (FileStatus file : files) {
				System.out.println(file.getPath());
			}
		}
	}

	// 上传本地文件到HDFS
	public void UploadFileToHDFS(String localpath, String hdfspath)
			throws Exception {

		Configuration conf = new Configuration();
		// conf.addResource(new Path(localPath + "core-site.xml"));
		FileSystem hdfs = FileSystem.get(conf);
		Path src = new Path(localpath);
		Path dst = new Path(hdfspath);
		hdfs.copyFromLocalFile(src, dst);

		// 输出hdfs上目录中的文件列表
		HdfsFileList(dst);
	}

	// 创建HDFS文件，并对文件进行些内容
	public void CreateFile(String hdfspath) throws Exception {
		Configuration conf = new Configuration();
		// byte[] buff = "hello world!".getBytes();
		Scanner sc = new Scanner(System.in);
		System.out.println("请输入一行字符串");
		String src = sc.nextLine();// 在控制台获取一行字符串

		FileSystem hdfs = FileSystem.get(conf);
		Path dst = new Path(hdfspath);
		FSDataOutputStream outputStream = null;
		try {
			outputStream = hdfs.create(dst);
			// 将这一行字符串写入文件中
			outputStream.writeBytes(src); // write(buff, 0, buff.length);
		} catch (Exception e) {
			e.printStackTrace();

		} finally {
			if (outputStream != null) {
				outputStream.close();
			}
		}

		HdfsFileList(dst.getParent());
	}

	// 重命名HDFS文件

	public void RenameFileName(String oldname, String newname) throws Exception {

		Configuration conf = new Configuration();

		FileSystem hdfs = FileSystem.get(conf);
		// Path dst = new Path(hdfspath);

		Path frpath = new Path(oldname);
		Path topath = new Path(newname);

		hdfs.rename(frpath, topath);

		HdfsFileList(topath.getParent());
	}

	// 刪除HDFS文件或目录
	public void DelHDFSFiles(String hdfspath) throws Exception {

		Configuration conf = new Configuration();

		FileSystem hdfs = FileSystem.get(conf);
		// Path dst = new Path(hdfspath);

		Path topath = new Path(hdfspath);
		if(!hdfs.exists(topath)){
			System.out.println("文件不存在");
			return ;
		}
		
		boolean ok = hdfs.delete(topath, true);
		System.out.println(ok ? "删除成功" : "删除失败");

		HdfsFileList(topath.getParent());
	}

	// 查看HDFS文件或文件夹里所有文件的最后修改时间
	public void GetFileModifyTime(String hdfspath) throws Exception {

		Configuration conf = new Configuration();

		FileSystem hdfs = FileSystem.get(conf);
		Path dst = new Path(hdfspath);

		FileStatus files[] = hdfs.listStatus(dst);
		for (FileStatus file : files) {
			/*
			 * System.out.println(file.getPath() + "\t" +
			 * file.getModificationTime());
			 */

			System.out.println(file.getPath() + "\t"
					+ new Date(file.getModificationTime()));

		}
	}

	// 查看HDFS文件是否存在
	public boolean IsExists(String hdfspath) throws Exception {

		Configuration conf = new Configuration();

		FileSystem hdfs = FileSystem.get(conf);
		Path dst = new Path(hdfspath);

		boolean ok = hdfs.exists(dst);
		System.out.println(ok ? "文件存在" : "文件不存在");
		return ok;
	}

	// 查看某个文件在HDFS集群的位置
	public void FileBlockLocation(String hdfspath) throws Exception {

		Configuration conf = new Configuration();

		FileSystem hdfs = FileSystem.get(conf);
		Path dst = new Path(hdfspath);

		FileStatus fileStatus = hdfs.getFileStatus(dst);
		BlockLocation[] blockLocations = hdfs.getFileBlockLocations(fileStatus,
				0, fileStatus.getLen());
		for (BlockLocation block : blockLocations) {
			System.out.println(Arrays.toString(block.getHosts()) + "\t"
					+ Arrays.toString(block.getNames()) + "\t"
					+ block.getLength());
		}
	}

	// 获取HDFS集群上所有节点名称
	public void GetHostName() throws Exception {

		Configuration conf = new Configuration();

		DistributedFileSystem hdfs = (DistributedFileSystem) FileSystem
				.get(conf);
		DatanodeInfo[] dataNodeStats = hdfs.getDataNodeStats();

		for (DatanodeInfo dataNode : dataNodeStats) {
			System.out.println(dataNode.getHostName() + "\t"
					+ dataNode.getName());
		}
	}
}