hadoop的文件操作整理java

 package dada;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;

 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;

 public class HDFSToll {

     //路径是否存在
     public static boolean testExist(Configuration conf,String path) throws  IOException
     {
         FileSystem fs=FileSystem.get(conf);
         return fs.exists(new Path(path));
     }
     //创建目录
     public static boolean mkdir (Configuration conf ,String remoteDir)throws IOException
     {
     FileSystem fs=FileSystem.get(conf);
     Path dirPath=new Path(remoteDir);
     boolean result=fs.mkdirs(dirPath);
     fs.close();
     return result;
     }
     /**
      * 删除目录
      */
     public static boolean rmDir(Configuration conf, String remoteDir) throws IOException {
         FileSystem fs = FileSystem.get(conf);
         Path dirPath = new Path(remoteDir);
         /* 第二个参数表示是否递归删除所有文件 */
         boolean result = fs.delete(dirPath, true);
         fs.close();
         return result;
     }
     //创建文件
     public static void touch(Configuration conf,String remoteFilePath )throws IOException
     {
         FileSystem fs=FileSystem.get(conf);
         Path remotePath=new Path(remoteFilePath);
         FSDataOutputStream outputStream =fs.create(remotePath);
         outputStream.close();
         fs.close();
     }
     //删除文件
     public static boolean rm(Configuration conf,String remoteFilePath)throws IOException
     {
         FileSystem fs=FileSystem.get(conf);
         Path remotePath=new Path(remoteFilePath);
         boolean result=fs.delete(remotePath,false);
         fs.close();
         return result;
     }
     //追加文件内容  到末尾
     public static void appendContentToFile(Configuration conf,String content,String remoteFilePath)throws IOException
     {
         FileSystem fs=FileSystem.get(conf);
         Path remotePath=new Path(remoteFilePath);
         FSDataOutputStream out=fs.append(remotePath);
         out.write(content.getBytes());
         out.close();
         fs.close();
     }

     //追加文件内容到开头
     public static void appendContentToFile1(Configuration conf,String content,String remoteFilePath)throws IOException
     {
           String localTmpPath = "/usr/local/hadoop/enen.txt";

           // 移动到本地
           moveToLocalFile(conf, remoteFilePath, localTmpPath);
           // 创建一个新文件
           touch(conf, remoteFilePath);
           // 先写入新内容
          appendContentToFile(conf, content, remoteFilePath);
           // 再写入原来内容
           appendContentToFile(conf, localTmpPath, remoteFilePath); 

           System.out.println("已追加内容到文件开头: " + remoteFilePath);
     }
     /**

      * 复制文件到指定路径

      * 若路径已存在，则进行覆盖

      */

     public static void copyFromLocalFile(Configuration conf, String localFilePath, String remoteFilePath) throws IOException {

         FileSystem fs = FileSystem.get(conf);

         Path localPath = new Path(localFilePath);

         Path remotePath = new Path(remoteFilePath);

         /* fs.copyFromLocalFile 第一个参数表示是否删除源文件，第二个参数表示是否覆盖 */

         fs.copyFromLocalFile(false, true, localPath, remotePath);

         fs.close();

     }

     //将文件1写入文件2
     public static void appendFile1ToFile2(Configuration conf,String  remoteFilePath,String remoteFilePath2)throws IOException
     {
         FileSystem fs=FileSystem.get(conf);
         Path file=new Path(remoteFilePath);
         FSDataInputStream  getIt=fs.open(file);
         BufferedReader d=new BufferedReader(new InputStreamReader(getIt));
         String content1=d.readLine();
         Path remotePath=new Path(remoteFilePath2);
         FSDataOutputStream out=fs.append(remotePath);
         out.write(content1.getBytes());
         d.close();
         out.close();
         fs.close();
     }
     /**

      * 追加文件内容

      */
     public static void appendToFile(Configuration conf, String localFilePath, String remoteFilePath) throws IOException {

         FileSystem fs = FileSystem.get(conf);

         Path remotePath = new Path(remoteFilePath);

         /* 创建一个文件读入流 */

         FileInputStream in = new FileInputStream(localFilePath);

         /* 创建一个文件输出流，输出的内容将追加到文件末尾 */

         FSDataOutputStream out = fs.append(remotePath);

         /* 读写文件内容 */

         byte[] data = new byte[1024];

         int read = -1;

         while ( (read = in.read(data)) > 0 ) {

             out.write(data, 0, read);

         }

         out.close();

         in.close();

         fs.close();

     }
     /**

      * 下载文件到本地

      * 判断本地路径是否已存在，若已存在，则自动进行重命名

      */

     public static void copyToLocal(Configuration conf, String remoteFilePath, String localFilePath) throws IOException {

         FileSystem fs = FileSystem.get(conf);

         Path remotePath = new Path(remoteFilePath);

         File f = new File(localFilePath);

         /* 如果文件名存在，自动重命名(在文件名后面加上 _0, _1 ...) */

         if (f.exists()) {

             System.out.println(localFilePath + " 文件已存在.");

             Integer i = 0;

             while (true) {

                 f = new File(localFilePath + "_" + i.toString());

                 if (!f.exists()) {

                     localFilePath = localFilePath + "_" + i.toString();

                     System.out.println("将重新命名为: " + localFilePath);

                     break;//重命名文件 

                 }

                 i++;

             }

            // System.out.println("将重新命名为: " + localFilePath);

         }

         else

             System.out.println(localFilePath + " 文件不存在.");

         // 下载文件到本地

        Path localPath = new Path(localFilePath);

        fs.copyToLocalFile(remotePath, localPath);

        fs.close();

     }
     /**
      * 移动文件到本地

      * 移动后，删除源文件

      */
     public static void moveToLocalFile(Configuration conf, String remoteFilePath, String localFilePath) throws IOException {

         FileSystem fs = FileSystem.get(conf);

         Path remotePath = new Path(remoteFilePath);

         Path localPath = new Path(localFilePath);

         fs.moveToLocalFile(remotePath, localPath);

     }
 }