JAVA 编写的 医院管理系统,利用ACCESS做的数据库.

				package hospital.db;
				
				import java.sql.*;
				
				/**
				 * 本类用于与数据库建立接
				 *
				 * 作者：Fido Dido
				 */
				public abstract class DBConnection{
				  private static Connection conn=null;
				  private static String m_strErrMsg;
				
				  public static String getErrMsg()
				  {
				    return m_strErrMsg;
				  }
				
				  public static boolean TestConn()
				  {
				    try
				    {
				      if(conn == null){
				        Class.forName("com.mysql.jdbc.Driver");
				        conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/hospital","root","");
				        Debug.log("Connecion created.");
				        conn.close();
				      }
				      m_strErrMsg = "连接成功!";
				  }
				  catch(Exception ex)
				  {
				//    Debug.log(Debug.getExceptionMsg(ex));
				    m_strErrMsg = ex.getLocalizedMessage();
				    return false;
				  }
				  return true;
				}
				
				
				  /**
					 * 与数据库建立连接
					 *
					 * 返回值－Connection对象
					 */
					public static Connection getConnection(){
						try{
							if(conn == null){
								Class.forName("com.mysql.jdbc.Driver");
								conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/hospital","root","");
								Debug.log("Connecion created.");
							}
				
							else{
								Statement stmt=conn.createStatement();
								ResultSet rs=stmt.executeQuery("SELECT COUNT(*) FROM administrator");
								if(rs==null||!rs.next()){
									Class.forName("com.mysql.jdbc.Driver");
									conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/hospital","root","root");
									Debug.log("Connecion re-created.");
								}
				
							}
						}
						catch(Exception ex){
							Debug.log(Debug.getExceptionMsg(ex));
						}
						finally{
							return conn;
						}
					}
				}