hadoo分布式文件操作HDFS

小灰灰 2022-06-14 04:14 134阅读 0赞

**HDFS的java访问接口——FileSystem**

写文件 create 读取文件 open 删除文件delete 创建目录 mkdirs 删除文件或目录 delete 列出目录的内容 listStatus 显示文件系统的目录和文件的元数据信息 getFileStatus

**java 代码**

public class App2 { 
    
        static{
            URL.setURLStreamHandlerFactory(new FsUrlStreamHandlerFactory());
        }
    
        public static final  String HDFS_PATH = "hdfs://centos-node5:9000";
        public static final  String PATH_PATH = "/dl100";
        public static final  String FILE_PATH = "/dl100/f1000";
        /** * hadoop FileSystem 的文件操作 * @param args * @throws Exception */
        public static void main(String[] args) throws Exception {
            final FileSystem fileSystem = FileSystem.get(new URL(HDFS_PATH).toURI(),new Configuration());
    
            //创建文件夹
            //mkdirDirectroy(fileSystem);
    
            //上传文件
            //uploadData(fileSystem);
    
            //下载文件
            //downLoadData(fileSystem);
    
            //删除文件(夹)
            deleteFile(fileSystem);
        }
    
        private static void deleteFile(final FileSystem fileSystem)
                throws IOException {
            fileSystem.delete(new Path(FILE_PATH), true);
        }
    
        private static void downLoadData(final FileSystem fileSystem)
                throws IOException {
            final FSDataInputStream in = fileSystem.open(new Path(FILE_PATH));
            IOUtils.copyBytes(in, System.out, 1024, true);
        }
    
        private static void mkdirDirectroy(final FileSystem fileSystem)
                throws IOException {
            fileSystem.mkdirs(new Path(PATH_PATH));
        }
    
        private static void uploadData(final FileSystem fileSystem)
                throws IOException {
            final FSDataOutputStream out = fileSystem.create(new Path(FILE_PATH));
            final FileInputStream in = new FileInputStream("d:/log.txt");
            IOUtils.copyBytes(in, out, 1024, true);
        }
    
    }