How to export data from Cassandra to CSV file using Java -

-

i tried use datastax java driver, found out not support copy command, know other methods of exporting data using java? thanks.

for example have created event table:

cqlsh:kunderatest> describe table event ;  create table event (   id text,   log text,   timstamp bigint,   primary key (id) )

and inserted 3 record 

cqlsh:kunderatest> insert event (id, log , timstamp ) values ( '1', 'my first log' , 12345678); cqlsh:kunderatest> insert event (id, log , timstamp ) values ( '2', 'my second log' , 12345679); cqlsh:kunderatest> insert event (id, log , timstamp ) values ( '3', 'my third log' , 12345680);

1) first can using cqlsh client. can export data of event table file (in case log.txt) executing following command.

cqlsh:kunderatest>  copy kunderatest.sample (id, name, age, address) './log.txt' delimiter = '|' , quote = '''' , escape = '''' , null = '<null>'; 3 rows exported in 0.042 seconds.

you can validate command output verify log.txt file. hope you.

2) second can use runtime utility of java execute export command in order achieve goal.

  • create file (let command.txt) , paste following export command file.

    copy kunderatest.sample (id, name, age, address) './log.txt' delimiter = '|' , quote = '''' , escape = '''' , null = '<null>'

after creating file , adding above command file following export data file given in export command.

    string exportcommand = cassandrahome + "bin/cqlsh " + hostname + " " + rpcport + " -f command.txt"; // file holds export command      runtime runtime = runtime.getruntime();     process process = runtime.exec(exoprtcommand);      // keep tracking log, can following.      inputstream = process.getinputstream();     inputstreamreader isr = new inputstreamreader(is);     bufferedreader br = new bufferedreader(isr);     string line = null;      while ((line = br.readline()) != null)     {      }

note: cassandrahome path of cassandra package directory. in case /usr/local/apache-cassandra-2.0.6


Comments

Post a Comment

Popular posts from this blog

C# random value from dictionary and tuple -

-
i have following code, , need random item contains string "region_1" dictionary. public static dictionary<int, tuple<string, int, currencytype>> itemarray = new dictionary<int, tuple<string, int, currencytype>>() { { 0xb3e, new tuple<string, int, currencytype>("region_1", 1500, currencytype.fame) } }; public static int generateitemid(string shopid) { var generateditem = itemarray.elementat(new random().next(0, itemarray.count)).key; } how select this? it's not possible efficiently... first create static random @ class level... prevent non-random behaviour if run query on short period of time... (it's seeded discrete clock) static random rnd = new random(); then: var item = itemarray.values .where(t => t.item1 == shopid) .orderby(_ => rnd.next()) .firstordefault()
Read more

cgi - How do I interpret URLs without extension as files rather than missing directories in nginx? -

-
so i'm trying install zoneminder , have run under nginx, has few compiled files need run using fast-cgi. these files lack extension. if file has extension, there no issue , nginx interprets file , return 404 if can't find it. if has no extension, assume it's directory , return 404 when can't find sort of index page. here have now: # security camera domain. server { listen 888; server_name mydomain.com; root /srv/http/zm; # enable php support. include php.conf; location / { index index.html index.htm index.php; } # enable cgi support. location ~ ^/cgi-bin/(.+)$ { alias /srv/cgi-bin/zm/; fastcgi_pass unix:/run/fcgiwrap.sock; fastcgi_param script_filename $document_root/$1; include fastcgi.conf; } } the idea is, under cgi-bin directory goes through fastcgi pipe. any idea on howi can fix this? upon closer inspection, realized zoneminder has 2 cgi sc...
Read more

.htaccess - htaccess convert request to clean url and add slash at the end of the url -

-
ok , searched more 4 days , more 20 posts here in stach or in websites without kind of success first here htaccess file rewriteengine on rewriterule ^([a-za-z0-9_]+)/?$ index.php?page=$1 [nc] rewriterule ^([a-za-z0-9_]+)\/([a-za-z0-9_]+)\/?$ index.php?page=$1&action=$2 [nc] i tried many codes 1 worked me can call request , works me www.example.com/pagename => www.example.com/index.php?page=pagename here questions , please provide me information "in detail" understand code well 1- how convert request automatically www.example.com/index.php?page=pagename www.example.com/pagename 2- if tried add slash @ end shows me page without images or styling mean www.example.com/pagename => works www.example.com/pagename/ => doesn't work that's :) for first part need 301 rule this: rewritecond %{the_request} /index\.php\?page=([^\s&]+) [nc] rewriterule ^ /%1? [r=301,l] for second part use absolute path in css, js, images files r...
Read more