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基本实例化代码        System.setProperty("hadoop.home.dir", "/home/xm/hadoop-2.7.1");        String uri = "hdfs://master:9000";        Configuration conf = new Configuration();        FileSystem fs = FileSystem.get(URI.create(uri),conf);        Path path = new Path("hdfs://master:9000/input/input3.txt");

创建目录        Path path = new Path("hdfs://master:9000/input");        fs.mkdirs(path);

创建文件        Path path = new Path("hdfs://master:9000/input/input3.txt");        fs.createNewFile(path);

删除目录或者文件，路径修改即可        Path path = new Path("hdfs://master:9000/input/input3.txt");        fs.delete(path);

文件写入代码        Path path = new Path("hdfs://master:9000/input/input3.txt");         FSDataOutputStream out = fs.create(path);           out.writeUTF("hello hadoop!");

文件读出代码方法1（配合上面写入使用，否则可能出错）        Path path = new Path("hdfs://master:9000/input/input3.txt");        FSDataInputStream inStream = fs.open(path);          String data = inStream.readUTF();          System.out.println(data);          inStream.close();

文件读出方法2--万能代码（不乱码）        Path path = new Path("hdfs://master:9000/input/input3.txt");        InputStream in = null;        in = fs.open(path);        IOUtils.copyBytes(in, System.out, 4096);        IOUtils.closeStream(in);

本地文件内容导入HDFS文件代码        Path path = new Path("hdfs://master:9000/input/input3.txt");        String p = "/home/xm/aaaa";        InputStream in = new BufferedInputStream(new FileInputStream(p));        OutputStream out = null;        out = fs.create(path);        IOUtils.copyBytes(in, out, 4096,true);        IOUtils.closeStream(in);        IOUtils.closeStream(out);

本地文件追加至HDFS文件        Path path = new Path("hdfs://master:9000/input/input3.txt");        String p = "/home/xm/aaaa";        InputStream in = new BufferedInputStream(new FileInputStream(p));        OutputStream out = null;        out = fs.append(path);        IOUtils.copyBytes(in, out, 4096, true);        IOUtils.closeStream(in);        IOUtils.closeStream(out);追加若出错加上        conf.setBoolean( "dfs.support.append", true );        conf.set("dfs.client.block.write.replace-datanode-on-failure.policy", "NEVER");         conf.set("dfs.client.block.write.replace-datanode-on-failure.enable", "true");

自行追加(若出错希望知道的同学告诉改错方法写在下面)        FSDataOutputStream out = fs.append(path);        int readLen = "end hadoop!".getBytes().length;        while(-1!=readLen){            out.write("end hadoop".getBytes(),0,readLen);            break;        }        out.close();

本地文件导入到HDFS目录中        String srcFile = "/home/xm/aaaa";        Path srcPath = new Path(srcFile);        String dstFile = "hdfs://master:9000/input/";        Path dstPath = new Path(dstFile);        fs.copyFromLocalFile(srcPath,dstPath);

获取给定目录下的所有子目录以及子文件        getFile(path,fs);        public static void getFile(Path path,FileSystem fs) throws IOException, IOException{        FileStatus[] fileStatus = fs.listStatus(path);        for(int i=0;i

查找某个文件在HDFS集群的位置        Path path = new Path("hdfs://master:9000/input/input3.txt");        FileStatus status = fs.getFileStatus(path);        BlockLocation[]locations = fs.getFileBlockLocations(status, 0, status.getLen());        int length = locations.length;        for(int i=0;i

HDFS集群上所有节点名称信息        DistributedFileSystem dfs = (DistributedFileSystem) fs;        DatanodeInfo[]dataNodeStats = dfs.getDataNodeStats();        for(int i=0;i

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