How do I to write an entire table to a flat file (text file) using jdbc? So far I've attempted the following:
Statement statement = connection.createStatement(); ResultSet result = statement.executeQuery("SELECT * FROM tablename"); BufferedInputStream buffer; FileOutputStream out = new FileOutputStream("flatfile.txt"); while(result.next() ) { buffer = new BufferedInputStream(result.getBinaryStream("????") ); byte[] buf = new byte[4 * 1024]; //4K buffer int len; while( (len = buffer.read(buf, 0, buf.length) ) != -1 ) { out.write(buf, 0, len ); } } out.close();
"????" is just my placeholder. I am stuck on what to pass in as an argument.
You can get the column count in a table using the getColumnCount() method of the ResultSetMetaData interface. On invoking, this method returns an integer representing the number of columns in the table in the current ResultSet object.
We can use getX() method to get the data of the columns while iterating through the results where X – is the datatype of the column. We can use either Column Names or Index to get the values using getX() methods. We can also mention index number of the Column instead of Column Name in the getX() methods.
You can get all the column names and the entire data from your table using the code below. writeToFile method will contain the logic to writing to file (if that was not obvious enough :) )
ResultSetMetaData metadata = rs.getMetaData(); int columnCount = metadata.getColumnCount(); for (int i = 1; i <= columnCount; i++) { writeToFile(metadata.getColumnName(i) + ", "); } System.out.println(); while (rs.next()) { String row = ""; for (int i = 1; i <= columnCount; i++) { row += rs.getString(i) + ", "; } System.out.println(); writeToFile(row); }
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