實驗1HDFSJavaAPI編程

1、實驗1 HDFS Java API編程一、實驗目的1、理解HDFSB Hadoop體系結(jié)構(gòu)中的角色；2、熟悉HDFSt作常用的Java API。二、實驗平臺操作系統(tǒng)：LinuxHadoop版本：或以上版本JDK版本：或以上版本Java IDE : Eclipse三、實驗內(nèi)容利用HDFS勺Java API編程實現(xiàn)以下指定功能：1、文件讀寫：通過FSDataOutputStream 將文件內(nèi)容寫入 HDFS通過FSDataInputStream從HDF計讀取文件內(nèi)容。Java代碼：package .*;public class MyTest1 public static void main(Str

2、ing口 args) throws IOException Configuration conf = new Configuration。；("","");("","");FileSystem fs = (conf);Path filePath = new Path("/user/hadoop/");public class MyTest2 public static boolean test(Configuration conf, String path)throws IOException

3、FileSystem fs = (conf);return (new Path(path);public static void copyFromLocalFile(Configuration conf,String localFilePath, String remoteFilePath) throws IOException FileSystem fs = (conf);Path localPath = new Path(localFilePath);Path remotePath = new Path(remoteFilePath);/*第一個參數(shù)表示是否刪除源文件，第二個參數(shù)表示是否覆

4、蓋*/(false, true, localPath, remotePath);();public static void appendToFile(Configuration conf, String localFilePath,String remoteFilePath) throws IOException FileSystem fs = (conf);Path remotePath = new Path(remoteFilePath);/*創(chuàng)建一個文件讀入流*/FileInputStream in = new FilelnputStream(localFilePath);/*創(chuàng)建一個文

5、件輸出流，輸出的內(nèi)容將追加到文件末尾*/FSDataOutputStream out = (remotePath);/*讀寫文件內(nèi)容*/byte口 data = new byte1024;int read = -1;while (read = (data) > 0) (data, 0, read);();();();public static void main(String口 args) Configuration conf = new Configuration。；("","");("","");(&qu

6、ot;", "NEVER");("", "true");String localFilePath = "/home/hadoop/" else + " 不存在.");/*進行處理*/if (!fileExists) 5public class MyTest3 /*下載文件到本地判斷本地路徑是否已存在，若已存在，則自動進行重命名*/public static void copyToLocal(Configuration conf, String remoteFilePath,String

7、 localFilePath) throws IOException FileSystem fs = (conf);Path remotePath = new Path(remoteFilePath);File f = new File(localFilePath);/*如果文件名存在，自動重命名(在文件名后面加上 _0, _1)*/if () + " 已存在.");Integer i = 0;while (true) f = new File(localFilePath + "_" + ();if (!() localFilePath = localF

8、ilePath + "_" + ();break;i+;"將重新命名為："+ localFilePath);public class MyTest4 /*讀取文件內(nèi)容*/public static void cat(Configuration conf, String remoteFilePath)throws IOException FileSystem fs = (conf);Path remotePath = new Path(remoteFilePath);FSDataInputStream in = (remotePath);BufferedR

9、eader d = new BufferedReader(new InputStreamReader(in);String line = null;while (line = () != null) ();();();public static void main(String口 args) Configuration conf = new Configuration。；("","");String remoteFilePath = "/user/hadoop/"public class MyTest5 /*刪除文件*/public

10、static boolean rm(Configuration conf, String remoteFilePath)throws IOException FileSystem fs = (conf);Path remotePath = new Path(remoteFilePath);boolean result = (remotePath, false);();return result;public static void main(String口 args) Configuration conf = new Configuration。；("","");String remoteFilePath = "/user/hadoop/&