Example: Migrating Data from MY
The following example shows how to use CopyManager to migrate data from MY to GaussDB. Before executing the code in this example, load the driver first. For details about how to obtain and load the driver, see JDBC Package, Driver Class, and Environment Class.
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import java.io.StringReader; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import org.postgresql.copy.CopyManager; import org.postgresql.core.BaseConnection; public class Migration{ public static void main(String[] args) { String url = new String("jdbc:postgresql://10.180.155.74:8000/postgres"); // Database URL String user = new String("jack"); //GaussDB username String pass = new String("xxxxxxxxx"); //GaussDB password String tablename = new String("migration_table"); // Table information String delimiter = new String("|"); // Delimiter String encoding = new String("UTF8"); // Character set String driver = "org.postgresql.Driver"; StringBuffer buffer = new StringBuffer(); // Buffer to store formatted data try { // Obtain the query result set of the source database. ResultSet rs = getDataSet(); // Traverse the result set and obtain records row by row. // The values of columns in each record are separated by the specified delimiter and end with a linefeed, forming strings. // Add the strings to the buffer. while (rs.next()) { buffer.append(rs.getString(1) + delimiter + rs.getString(2) + delimiter + rs.getString(3) + delimiter + rs.getString(4) + "\n"); } rs.close(); try { // Connect to the target database. Class.forName(driver); Connection conn = DriverManager.getConnection(url, user, pass); BaseConnection baseConn = (BaseConnection) conn; baseConn.setAutoCommit(false); // Initialize the table. String sql = "Copy " + tablename + " from STDIN DELIMITER " + "'" + delimiter + "'" + " ENCODING " + "'" + encoding + "'"; // Commit data in the buffer. CopyManager cp = new CopyManager(baseConn); StringReader reader = new StringReader(buffer.toString()); cp.copyIn(sql, reader); baseConn.commit(); reader.close(); baseConn.close(); } catch (ClassNotFoundException e) { e.printStackTrace(System.out); } catch (SQLException e) { e.printStackTrace(System.out); } } catch (Exception e) { e.printStackTrace(); } } //******************************** // Return the query result set from the source database. //********************************* private static ResultSet getDataSet() { ResultSet rs = null; try { Class.forName("com.MY.jdbc.Driver").newInstance(); Connection conn = DriverManager.getConnection("jdbc:MY://10.119.179.227:3306/jack?useSSL=false&allowPublicKeyRetrieval=true", "jack", "xxxxxxxxx"); Statement stmt = conn.createStatement(); rs = stmt.executeQuery("select * from migration_table"); } catch (SQLException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } return rs; } } |
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