讀取hdfs上的檔案

上傳檔案在hdfs上，通路namenode節點：ip:50070

讀取hdfs的java代碼如下：

public void ReadFile(String hdfs) throws IOException {
          Configuration conf = new Configuration();
          FileSystem fs = FileSystem.get(URI.create(hdfs),conf);
          System.out.println(URI.create(hdfs));
          //fs.listFiles(f, recursive)
          FileStatus[] status = fs.listStatus(new Path(hdfs));
            for (FileStatus file : status) {
                System.out.println(file.getPath().getName());
                if (!file.getPath().getName().endsWith(".txt")) {
                    continue;
                }
                System.out.println(file.getPath().getName());
          FSDataInputStream hdfsInStream = fs.open(file.getPath());      
          byte[] ioBuffer = new byte[];
          int readLen = hdfsInStream.read(ioBuffer);
          while(readLen!=-)
          {           
           System.out.write(ioBuffer, , readLen);
           readLen = hdfsInStream.read(ioBuffer);
          }
          hdfsInStream.close();
         // fs.close();

         }
         }
           

public static void main(String[] args) throws IOException { 
          String hdfs = "hdfs://ip:8020/檔案夾";
          text t = new text(); 
          //t.WriteFile(hdfs);
          t.ReadFile(hdfs);

          }
           

建立目錄：

public static void mkdir(String dir) throws IOException  
        {  
            Configuration conf = new Configuration();  
            FileSystem fs = FileSystem.get(conf);  
            fs.mkdirs(new Path(dir));  
            fs.close();  
        }  
           

寫入hdfs中：

public void WriteFile(String hdfs) throws IOException { Configuration conf = new Configuration(); FileSystem fs = FileSystem.get(URI.create(hdfs),conf); FSDataOutputStream hdfsOutStream = fs.create(new Path(hdfs)); hdfsOutStream.writeChars("hello"); hdfsOutStream.close(); fs.close(); }