Solve the Problem of Java. Lang. classnotfoundexception: org. Apache. hadoop. Examples. wordcount $ token when running wordcount in eclipse.

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 1   Package  Org. Apache. hadoop. examples;  2    3    Import  Java. Io. file;  4    Import  Java. Io. fileinputstream;  5    Import  Java. Io. fileoutputstream;  6    Import Java. Io. ioexception;  7    Import  Java.net. url;  8    Import  Java.net. urlclassloader;  9    Import  Java. util. arraylist;  10    Import  Java. util. List;  11    Import  Java. util. Jar. jarentry; 12    Import  Java. util. Jar. jaroutputstream;  13    Import  Java. util. Jar. manifest;  14    15    Public   Class  Ejob {  16    17        //  To declare Global Field  18       Private   Static List <URL> classpath = New Arraylist <URL> ();  19    20        //  To declare Method  21        Public   Static File createtempjar (string root) Throws  Ioexception {  22            If (!New  File (Root). exists ()){  23                Return   Null  ;  24   }  25 Manifest manifest = New  Manifest ();  26 Manifest. getmainattributes (). putvalue ("manifest-version", "1.0" );  27            Final File jarfile = file. createtempfile ("ejob-", ". Jar ", New  File (  28 System. getproperty ("Java. Io. tmpdir" )));  29    30 Runtime. getruntime (). addshutdownhook ( New  Thread (){  31                Public   Void  Run (){  32   Jarfile. Delete (); 33   }  34   });  35    36 Jaroutputstream out = New  Jaroutputstream (  37                    New  Fileoutputstream (jarfile), manifest );  38 Createtempjarinner (Out, New File (Root ),"" );  39  Out. Flush ();  40   Out. Close ();  41            Return  Jarfile;  42   }  43    44        Private   Static   Void  Createtempjarinner (jaroutputstream out, file F,  45 String Base)Throws  Ioexception {  46            If  (F. isdirectory ()){  47 File [] FL = F. listfiles ();  48                If (Base. Length ()> 0 ){  49 Base = base + "/" ;  50   }  51               For ( Int I = 0; I <Fl. length; I ++ ){  52 Createtempjarinner (Out, FL [I], base + FL [I]. getname ());  53   }  54 } Else  {  55 Out. putnextentry ( New  Jarentry (base ));  56 Fileinputstream in = New  Fileinputstream (f );  57                Byte [] Buffer = New   Byte [1024 ];  58                Int N = In. Read (buffer );  59                While (N! =-1 ){  60 Out. Write (buffer, 0, N );  61 N = In. Read (buffer );  62   }  63   In. Close ();  64   }  65   }  66    67        Public   Static  Classloader getclassloader (){ 68 Classloader parent = Thread. currentthread (). getcontextclassloader ();  69            If (Parent = Null  ){  70 Parent = ejob. Class  . Getclassloader ();  71   }  72            If (Parent = Null ){  73 Parent = Classloader. getsystemclassloader ();  74   }  75            Return   New Urlclassloader (classpath. toarray ( New URL [0 ]), Parent );  76   }  77    78        Public  Static   Void  Addclasspath (string component ){  79    80            If (Component! = Null ) & (Component. Length ()> 0 )){  81                Try  {  82 File F = New  File (component );  83   84                    If  (F. exists ()){  85 URL key = F. getcanonicalfile (). tourl ();  86                        If (! Classpath. Contains (key )){  87   Classpath. Add (key );  88   }  89   } 90 } Catch  (Ioexception e ){  91   }  92   }  93   }  94    95 }

 

Add the following to the mian method:

File jarfile = ejob. createtempjar ("Bin");

Ejob. addclasspath ("/Usr/hadoop/conf");

Classloader = ejob. getclassloader ();

Thread. currentthread (). setcontextclassloader (classloader );

...

(Jobconf) job. getconfiguration (). setjar (jarfile. tostring ());