Prentice Hall and Sun Microsystems. Personal use only; do not redistribute.
500
Chapter 18 JDBC and Database Connection Pooling
Listing 18.18 PreparedStatements.java (continued)
  public static void doRawQueries(Connection conn,
                                  boolean print) {
    try {
      String queryFormat =
        "SELECT lastname FROM employees WHERE salary > ";
      Statement statement = conn.createStatement();
      long startTime = System.currentTimeMillis();
      for(int i=0; i<40; i++) {
        ResultSet results =
          statement.executeQuery(queryFormat + (i*5000));
        if (print) {
          showResults(results);
        }
      }
      long stopTime = System.currentTimeMillis();
      double elapsedTime = (stopTime   startTime)/1000.0;
      System.out.println("Executing raw query " +
                         "40 times took " +
                         elapsedTime + " seconds.");
    } catch(SQLException sqle) {
      System.out.println("Error executing query: " + sqle);
    }
  } 
  private static void showResults(ResultSet results)
      throws SQLException {
    while(results.next()) {
      System.out.print(results.getString(1) + " ");
    }
    System.out.println();
  }
    
  private static Connection getConnection(String driver,
                                          String url,
                                          String username,
                                          String password) {
    try {
      Class.forName(driver);
      Connection connection =
        DriverManager.getConnection(url, username, password);
      return(connection);
    } catch(ClassNotFoundException cnfe) {
      System.err.println("Error loading driver: " + cnfe);
      return(null);
    } catch(SQLException sqle) {
      System.err.println("Error connecting: " + sqle);
      return(null);
    }
  }
Second edition of this book: www.coreservlets.com; Sequel: www.moreservlets.com.
Servlet and JSP training courses by book's author: courses.coreservlets.com.






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