一、準備階段

首先配置本機的環境變數，配置好HADOOP_HOME；在eclipse中安裝好外掛，以便在eclipse中操作HDFS叢集，將hadoop-eclipse-plugin-2.6.0.jar包放入到eclipse安裝資料夾下的dropins資料夾中的plugins下，此後重啟eclipse即可在eclipse中操作hdfs叢集。 注意： 編寫的程式碼若有操作檔案（例如修改、刪除等功能）時，需要在本機配置許可權的環境變數：HADOOP_USER_NAME=root，這樣才會避免在eclipse中出現許可權問題。

二、eclipse中的配置

環境變數配置好後，在eclipse中完成配置即可操作hdfs叢集： 1）eclipse中的Hadoop控制平臺

2）配置好所要連線的namenodeIP地址 此前要修改本機的hosts檔案來確定IP地址對應的主機名 3）操作 4）替換工程對應的Hadoop包下的bin資料夾，使其方便操作 5）匯入工程必需的jar包

三、JavaAPI程式碼

/**
 * 1、檢視檔案
 * 2、建立新資料夾
 * 3、上傳檔案
 * 4、下載檔案
 * 5、刪除檔案
 * 6、內部移動
 * 7、內部複製
 * 8、重新命名
 * 9、建立新的檔案
 * 10、寫檔案
 * 11、讀檔案內容
 * 
 */
    //操作HDFS之前得先建立配置物件
	Configuration conf = new Configuration(true);
	//建立操作HDFS的物件
	FileSystem fs = FileSystem.get(conf);
 

功能API程式碼：

//獲取資料的位置
	private static void getFileLocation(FileSystem fs, String string) throws IOException {
		FileStatus fileStatus = fs.getFileStatus(new Path(string));
		long len = fileStatus.getLen();
		BlockLocation[] fileBlockLocations = fs.getFileBlockLocations(fileStatus, 0, len);
		String[] hosts = fileBlockLocations[0].getHosts();
		for (String string2 : hosts) {
			System.out.println(string2);
		}
		
		HdfsBlockLocation blockLocation = (HdfsBlockLocation)fileBlockLocations[0];
		long blockId = blockLocation.getLocatedBlock().getBlock().getBlockId();
		System.out.println(blockId);
	}
//讀檔案內容
	private static void readFromHDFSFile(FileSystem fs, String string) throws IllegalArgumentException, IOException {
		FSDataInputStream inputStream = fs.open(new Path(string));
		FileStatus fileStatus = fs.getFileStatus(new Path(string));
		long len = fileStatus.getLen();
		
		byte[] b = new byte[(int)len];
		int read = inputStream.read(b);
		while(read != -1){
			System.out.println(new String(b));
			read = inputStream.read(b);
		}
	}
//寫檔案
private static void writeToHDFSFile(FileSystem fs, String filePath, String content) throws IllegalArgumentException, IOException {
		 FSDataOutputStream outputStream = fs.create(new Path(filePath));
		 outputStream.write(content.getBytes("UTF-8"));
		 outputStream.flush();
		 outputStream.close();
	}
//建立一個新檔案
private static void createNewFile(FileSystem fs, String string) throws IllegalArgumentException, IOException {
	fs.createNewFile(new Path(string));
}

//內部移動 內部複製
private static void innerCopyAndMoveFile(FileSystem fs, Configuration conf,String src, String dest) throws IOException {
	Path srcPath = new Path(src);
	Path destPath = new Path(dest);
	//內部拷貝
	FileUtil.copy(srcPath.getFileSystem(conf), srcPath, destPath.getFileSystem(conf), destPath,false, conf);
	//內部移動
	FileUtil.copy(srcPath.getFileSystem(conf), srcPath, destPath.getFileSystem(conf), destPath,true, conf);
}

//重新命名
private static void renameFile(FileSystem fs, String src, String dest) throws IOException {
	Path srcPath = new Path(src);
	Path destPath = new Path(dest);
	fs.rename(srcPath, destPath);
}

//下載檔案
private static void downLoadFileFromHDFS(FileSystem fs, String src, String dest) throws IOException {
	Path srcPath = new Path(src);
	Path destPath = new Path(dest);
	//copyToLocal
	fs.copyToLocalFile(srcPath, destPath);
	//moveToLocal
	fs.copyToLocalFile(true,srcPath, destPath);
}
//上傳檔案
private static void uploadFileToHDFS(FileSystem fs, String src, String dest) throws IOException {
	Path srcPath = new Path(src);
	Path destPath = new Path(dest);
	//copyFromLocal
	fs.copyFromLocalFile(srcPath, destPath);
	//moveFromLocal
	fs.copyFromLocalFile(true,srcPath, destPath);
}
//建立資料夾
private static void createDir(FileSystem fs, String string) throws IllegalArgumentException, IOException {
	Path path = new Path(string);
	if(fs.exists(path)){
		fs.delete(path, true);
	}
	fs.mkdirs(path);
}
//檢視檔案系統的內容
private static List listFileSystem(FileSystem fs, String path) throws FileNotFoundException, IOException {
	Path ppath = new Path(path);	
	FileStatus[] listStatus = fs.listStatus(ppath);		
	for (FileStatus fileStatus : listStatus) {
		System.out.println(fileStatus.getPath());
	}
	return null;
}

//刪除檔案
private static String del(String path) throws IOException{
			Configuration conf=new Configuration(true);
			FileSystem fs = FileSystem.get(conf);
			Path ppath=new Path(path);
			try {
				fs.delete(ppath);
				fs.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
			System.out.println("刪除檔案："+ppath);
		}