setupdatabase.java

Java经典例程 从外国一大学计算机教授出版物下载的代码 经典

import java.sql.*;
import javagently.*;
import java.io.*;

class SetUpDatabase {

  /* Database setup program        by B Worrall August 2000
   * ======================        amended by J M Bishop
   *
   * Sets up a database of rates data
   * as read in. The database uses Sun's
   * jdbc:odbc driver to connect to a text based
   * Access Database.
   */

  private Connection conn;

  SetUpDatabase() {
    // Load JDBC-ODBC Bridge driver
    try {
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
    } catch (ClassNotFoundException c) {
      System.out.println("Could not load database driver.");
    }

    // Read the data from the text file and store it in the
    // database.
    try {
      OpenConnection();
      WriteData();
    } catch (SQLException s) {
      System.out.println(s);
    } catch (IOException i) {
      System.out.println(i);
    }
  }

  void OpenConnection() throws SQLException {
    conn = DriverManager.getConnection("jdbc:odbc:Rates");
    Statement s = conn.createStatement();
    String state = "DROP TABLE rates";
    try {
      // Delete old data if necessary (if no such data,
      // exception is flagged and we carry on)
      int temp = s.executeUpdate(state);
    } catch (SQLException q) {}

    // Create table with columns in database
    state = "CREATE TABLE rates (Code VARCHAR(3), Country VARCHAR(80), " +
      "Curr VARCHAR(30), Conv DOUBLE)";
    int temp = s.executeUpdate(state);
  }

  void WriteData() throws IOException, SQLException {
    Stream fin = new Stream("rates.data", Stream.READ);
    try {
      for (; ;) {
        Rates r = new Rates();
        r.setRate(fin);
        // add data into rates
        Statement s = conn.createStatement();
        String state = "INSERT INTO rates VALUES ('" +
                       r.code + "', '" +
                       r.country + "', '" +
                       r.currency + "', " +
                       r.conversion + ")";
       int rs = s.executeUpdate(state);
     }
   } catch (EOFException e) {}
  }

  public static void main (String [] args) {
    new SetUpDatabase();
  }
}