buildemployee.java

大量java源程序

/*
 * @(#)BuildEmployee
 *
 * Copyright (c) 1998 Karl Moss. All Rights Reserved.
 *
 * You may study, use, modify, and distribute this software for any
 * purpose provided that this copyright notice appears in all copies.
 *
 * This software is provided WITHOUT WARRANTY either expressed or
 * implied.
 *
 * @author  Karl Moss
 * @version 1.0
 * @date    11Mar98
 *
 */

package javaservlets.db;

import java.sql.*;

/**
 * <p>This applications builds the sample employee database.
 */

public class BuildEmployee
{
  String m_tableName = "Employee";

  /**
    * <p>Main entry point for the application
    *
    * The usage for the application is:
    *
    *   BuildEmployee <driver> <URL> [<user>] [<password>]
    *
    * where
    *   driver   = the JDBC driver class name to use (such as
    *              sun.jdbc.odbc.JdbcOdbcDriver)
    *   URL      = the JDBC connection URL
    *   user     = the optional user name
    *   password = the optional password
    */
  public static void main(String args[])
    {
      String driver = null;
      String url = null;
      String user = null;
      String password = null;
      boolean needHelp = false;

      // Get the driver name
      if (args.length > 0) {
        driver = args[0];
      }
      else {
        needHelp = true;
      }

      // Get the URL
      if (args.length > 1) {
        url = args[1];
      }
      else {
        needHelp = true;
      }

      // Get the optional user name
      if (args.length > 2) {
        user = args[2];
      }

      // Get the optional password
      if (args.length > 3) {
        password = args[3];
      }

      // If the user needs help with the arguments, display it
      if (needHelp) {
        System.out.println("\nUsage: BuildEmployee <driver> " +
                           "<URL> [<user>] [<password>]");
      }
      else {
        BuildEmployee o = new BuildEmployee();
        o.build(driver, url, user, password);
      }
    }

  /**
    * <p>Build the database table
    *
    * @param driver JDBC driver class name
    * @param url JDBC connection URL
    * @param user User name
    * @param password User password
    */
  private void build(String driver, String url,
                     String user, String password)
    {
      java.sql.Connection con = null;
      java.sql.PreparedStatement ps = null;

      try {

        // Attempt to create a new instance of the specified
        // JDBC driver. Well behaved drivers will register
        // themselves with the JDBC DriverManager when they
        // are instantiated
        trace("Registering " + driver);
        java.sql.Driver d = (java.sql.Driver)
          Class.forName(driver).newInstance();

        // Create a connection to the given URL
        con = java.sql.DriverManager.getConnection(url, user,
                                                   password);

        // Create a new helper class
        SQLHelper helper = new SQLHelper(con);

        // Drop the table
        trace("Dropping existing " + m_tableName + " table");
        helper.drop(m_tableName);

        // Setup the columns
        ColumnDesc cols[] = new ColumnDesc[4];
        cols[0] = new ColumnDesc("Empno", Types.INTEGER);
        cols[1] = new ColumnDesc("Name", Types.VARCHAR);
        cols[2] = new ColumnDesc("Position", Types.VARCHAR);
        cols[3] = new ColumnDesc("Picture", Types.LONGVARBINARY);

        // Create the table
        trace("Creating table " + m_tableName);
        helper.create(m_tableName, cols);

        // Add data to the table
        ps = helper.prepareInsert(m_tableName, cols);

        add(ps, "001", "Nebby K. Nezzer", "President",
            "images/nezzer.jpg");
        add(ps, "002", "Mr. Lunt", "Foreman",
            "images/mrlunt.jpg");
        add(ps, "003", "Rack", "Jr. Executive",
            "images/bob.jpg");
        add(ps, "004", "Shack", "Jr. Executive",
            "images/junior.jpg");
        add(ps, "005", "Benny", "Jr. Executive",
            "images/larry.jpg");
        add(ps, "006", "George", "Security Guard",
            "images/george.jpg");
        add(ps, "007", "Laura", "Delivery Driver",
            "images/laura.jpg");
      }
      catch (Exception ex) {
        ex.printStackTrace();
      }
      finally {

        // Make sure we always clean up after ourselves
        if (con != null) {
          try {
            ps.close();
            con.close();
          }
          catch (Exception ex) {
          }
        }
      }

    }

  /**
    * <p>Adds a record to the Employee database with the
    * given parameters
    *
    * @param ps Prepared statement
    * @param Empno Employee number
    * @param Name Employee name
    * @param Position Employee position
    * @param Picture Name of an image file that contains the
    * employee's picture
    */
  private void add(java.sql.PreparedStatement ps,
                   String Empno, String Name, String Position,
                   String Picture)
    throws Exception
    {
      ps.setString(1, Empno);
      ps.setString(2, Name);
      ps.setString(3, Position);

      // Attempt to open an input stream
      java.io.FileInputStream in = null;
      int fileLen = 0;

      java.io.File f = new java.io.File(Picture);
      if (f.exists()) {
        fileLen = (int) f.length();
        in = new java.io.FileInputStream(f);
      }
      else {
        System.out.println("Note: " + Picture + " not found");
      }

      if (in == null) {
        ps.setNull(4, Types.LONGVARBINARY);
      }
      else {
        ps.setBinaryStream(4, in, fileLen);
      }

      ps.execute();

      // Close the input stream if necessary
      if (in != null) {
        in.close();
      }
    }

  /**
    * <p>Trace the given string
    */
  private void trace(String s)
    {
      System.out.println("BuildEmployee: " + s);
    }

}