Hello,
Thanks for your reply.
Following your suggestion, I tried to compile using the following command:
$ javac -classpath
/Users/arko/Documents/hadoop-0.21.0/hadoop-hdfs-0.21.0.jar -d class/
FileTest.java
I got the following errors:
FileTest.java:9: package org.apache.hadoop does not exist
import org.apache.hadoop.*;
^
FileTest.java:16: cannot find symbol
symbol : class Path
location: class FileTest
Path pt=new
Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc");
^
FileTest.java:16: cannot find symbol
symbol : class Path
location: class FileTest
Path pt=new
Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc");
^
FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be
accessed from outside package
FileSystem fs = FileSystem.get(new Configuration());
^
FileTest.java:17: cannot find symbol
symbol : class Configuration
location: class FileTest
FileSystem fs = FileSystem.get(new Configuration());
^
FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be
accessed from outside package
FileSystem fs = FileSystem.get(new Configuration());
^
6 errors
Many thanks in advance!
Warm regards
Arko
On Thu, Sep 1, 2011 at 10:13 PM, Rottinghuis, Joep <[email protected]>
wrote:
> Hadoop-hdfs will contain the HDFS (Hadoop FileSystem) classes.
>
> In your code you point to hdfs:// in your path, therefore you use HDFS,
> hence they are needed.
>
>
>
> Add the hdfs jar to your classpath and see if that improves things.
>
>
>
> Iif you organize imports on you class in an IDE such as Eclipse you’ll see
> that when you restrict the org.apache.hadoop.* import only to packages you
> need, that indeed you are using hdfs classes.
>
>
>
> Thanks,
>
>
>
> Joep
>
>
>
> From: Arko Provo Mukherjee [mailto:[email protected]]
> Sent: Wednesday, August 31, 2011 5:40 PM
> To: [email protected]
> Subject: Re: Compiling programs with Hadoop 0.21.0
>
>
>
> Hi,
>
>
>
> Thanks for the kind reply.
>
>
>
> If only the common and mapred are used, then what is
hadoop-hdfs-0.21.0.jar
> used for?
>
>
>
> My code looks like this:
>
>
>
> import java.util.*;
>
> import java.lang.*;
>
> import java.io.*;
>
> import org.apache.hadoop.*;
>
>
>
> class MapReduce {
>
>
>
> public static void main(String[] args) throws Exception {
>
> try {
>
> Path pt=new
> Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc");
>
> FileSystem fs = FileSystem.get(new Configuration());
>
> BufferedWriter br=new BufferedWriter(new
> OutputStreamWriter(fs.create(pt,true)));
>
> String line;
>
> line="Testing";
>
> System.out.println(line);
>
> br.write(line);
>
> br.close();
>
> }catch(Exception e){
>
> System.out.println("File not found");
>
> }
>
> }
>
> }
>
>
>
> When I compile the code, I get the following erros:
>
> $javac -classpath
> /Users/arko/Documents/hadoop-0.21.0/hadoop-common-0.21.0.jar -d class/
> FileSystemCat.java clear
>
>
>
> FileTest.java:16: cannot find symbol
>
> symbol : class Path
>
> location: class FileTest
>
> Path pt=new
> Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc");
>
> ^
>
> FileTest.java:16: cannot find symbol
>
> symbol : class Path
>
> location: class FileTest
>
> Path pt=new
> Path("hdfs://localhost:54310//Users/arko/Documents/Research/HDFS/abc");
>
> ^
>
> FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be
> accessed from outside package
>
> FileSystem fs = FileSystem.get(new Configuration());
>
> ^
>
> FileTest.java:17: cannot find symbol
>
> symbol : class Configuration
>
> location: class FileTest
>
> FileSystem fs = FileSystem.get(new Configuration());
>
> ^
>
> FileTest.java:17: java.io.FileSystem is not public in java.io; cannot be
> accessed from outside package
>
> FileSystem fs = FileSystem.get(new Configuration());
>
> ^
>
> 5 errors
>
>
>
> Thanks again for help!
> Warm Regards
>
> Arko
>
> On Wed, Aug 31, 2011 at 5:00 PM, Robert Evans <[email protected]> wrote:
>
> You should be able to use hadoop-common-0.21.0.jar for accessing HDFS APIS
> and use hadoop-mapred.0.21.0.jar for accessing the mapreduce APIs. I
cannot
> really comment further on compilation errors without seeing the code/error
> messages.
>
> --Bobby Evans
>
> On 8/31/11 4:34 PM, "Arko Provo Mukherjee" <[email protected]>
> wrote:
>
> Hello,
>
> I am trying to learn Hadoop and doing a project on it.
>
> I need to update some files in my project and hence wanted to use version
> 0.21.0
>
> However, I am confused as to how I can compile my programs on version
0.21.0
> as it doesn't have any hadoop-core-0.21.0.jar file. What option should I
> have to give in the -classpath option?
> I can see three different JAR files namely hadoop-common-0.21.0.jar,
> hadoop-hdfs-0.21.0.jar & hadoop-mapred-0.21.0.jar.
>
> I am getting compilation errors which using the the common jar file.
>
> Also I would like to learn the FileContext Library as the docs that I have
> read says that it has a simpler interface than the FileSystem. However, I
> cannot find any links to some example code which can help me to grasp the
> API. Request you to kindly share any link / code snippet
to demonstrate the
> use of the new API.
>
> Many thanks in advance for your kind response.
>
> Warm regards
> Arko
>
>
