创建通用数据库访问包装类

package skydev.modules.data;

import java.sql.*;

/**
 * 使用ODBC的方法：<br>
 * "sun.jdbc.odbc.JdbcOdbcDriver"<br>
 * "jdbc:odbc:" + odbcName<br>
 *
 * "oracle.thin.Driver"<br>
 * "qwe.sql.qweMySqlDriver"<br>
 * "symantec.dbanywhere.Driver"<br>
 *
 * 访问MS SQLServer的方法<br>
 * driveName="com.microsoft.jdbc.sqlserver.SQLServerDriver";<br>
 * url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=demo";<br>
 * 访问MySQL的方法：<br>
 * DBDriver=com.mysql.jdbc.Driver<br>
 * URL=jdbc:mysql://localhost/demo<br>
 */

public abstract class AbstractConnectionFactory {

  private String userName;
  private String password;
  private String driverName;
  private String url;
  private java.sql.Connection connection;
  /**
   * 工厂方法，返回实际创建的连接对象
   * @return
   */

  /**
   * 根据设置的连接参数创建一个新的连接实例
   * @return
   */
  private Connection getNewConnection() {
    try {
      this.connection.close(); //试图关闭连接
    }
    finally {
      this.connection = null; //释放连接
      try {
        Class.forName(this.driverName); //加载驱动程序
        try {
          this.connection = DriverManager.getConnection(this.url, this.userName,
              this.password);
        }
        catch (SQLException e) {
          throw e;
        }
      }
      finally {
        return this.connection; //返回新建立的连接
      }
    }
  }

  public String getUserName() {
    return userName;
  }

  public void setUserName(String userName) {
    this.userName = userName;
  }

  public String getPassword() {
    return password;
  }

  public void setPassword(String password) {
    this.password = password;
  }

  public String getDriverName() {
    return driverName;
  }

  public void setDriverName(String driverName) {
    this.driverName = driverName;
  }

  public String getUrl() {
    return url;
  }

  public void setUrl(String url) {
    this.url = url;
  }

  public java.sql.Connection getConnection() {
    if (connection != null) {
      try {