DELETE Hadoop SQL operation is used to delete a Hadoop SQL Query from the database.
Following code is used to delete a Hadoop SQL Query.
java.net.HttpURLConnection is used to create a DELETE request "hadoopsql" appended to the URL. Request property(hadoopsql-id) is set to id of the Hadoop SQL Query to be deleted.
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import org.apache.http.HttpStatus;
public class QueryOperations {
/*
* This program deletes a given Hadoop SQL Query
* @param serverURL: URL of s3 server.
* @param token: authorization token.
* @param queryId: Id of the query to be deleted
*/
public void deleteHadoopSQL(String serverURL, String token, String queryId)
throws Exception {
URL url = null;
HttpURLConnection httpCon = null;
InputStream is = null;
try {
/* append "/" at end of serverURL */
if (!serverURL.endsWith("/")) {
serverURL = serverURL + "/";
}
url = new URL(serverURL + "hadoopsql"); //append "hadoopsql" to the serverURL and create a new URL object
//Returns a URLConnection object that represents a connection to the remote object referred to by the URL.
httpCon = (HttpURLConnection) url.openConnection();
httpCon.setDoOutput(true); // to use the URL connection for output
httpCon.setRequestMethod("DELETE"); //DELETE request is used
httpCon.setRequestProperty("authorization", token); //provides authorization token for authentication
httpCon.setRequestProperty("hadoopsql-id", queryId); //provides id of the query to be deleted
httpCon.connect(); //Opens a communications link to the resource reference by the URL
if (httpCon.getResponseCode() == HttpStatus.SC_OK) { //check for OK response
is = httpCon.getInputStream();
// Process response here
}
} finally {
try {
if (is != null)
is.close(); //close InputStream
} catch (IOException e) {
e.printStackTrace();
}
if (httpCon != null) {
httpCon.disconnect(); //close connection
}
}
}
}