1 public final class DbConn 2 { 3 public static Connection getconn() 4  { 5 Connection conn = null; 6  7 String driver = "com.mysql.cj.jdbc.Driver"; 8 String user = "root"; 9 String passwd = "root";10 String url = "jdbc:mysql://localhost:3306/store?useSSL=false&serverTimezone=UTC";//指定要访问的数据库store11 12 //已加载完驱动13 try14  {15  Class.forName(driver); 16 conn = DriverManager.getConnection(url,user,passwd);17 }catch (SQLException e)18  {19  e.printStackTrace();20  }21 catch (ClassNotFoundException e)22  {23  e.printStackTrace();24  }25 return conn;26  }27 28 }

 1 public final class DbClose 2 { 3 /** 4  * 关闭 添加功能 资源 5  * @param pstmt,rs,conn 6 */ 7 public static void addClose(PreparedStatement pstmt, Connection conn) 8  { 9 /*10  * 多个 try-catch 出发点：安全11 */12 try13  {14 if (pstmt != null)15  {16  pstmt.close();17  }18 } catch (SQLException e1)19  {20  e1.printStackTrace();21  }22 try23  {24 if (conn != null)25  {26  conn.close();27  }28 } catch (SQLException e)29  {30  e.printStackTrace();31  }32  }33 34 /**35  * 关闭资源36  * @param pstmt,rs,conn37 */38 public static void queryClose(PreparedStatement pstmt, ResultSet rs, Connection conn)39  {40 try41  {42 if (pstmt != null)43  {44  pstmt.close();45  }46 } catch (SQLException e1)47  {48  e1.printStackTrace();49  }50 try51  {52 if (rs != null )53  {54  rs.close();55  }56 } catch (SQLException e1)57  {58  e1.printStackTrace();59  }60 try61  {62 if (conn != null)63  {64  conn.close();65  }66 } catch (SQLException e)67  {68  e.printStackTrace();69  }70  }71 72 }

测试代码。测试是否连接成功：

 1 public class Show { 2  3 public static void main(String[] args) { 4 //声明Connection对象 5  Connection con; 6 //驱动程序名 7 String driver = "com.mysql.cj.jdbc.Driver"; 8 //URL指向要访问的数据库名mydata 9 String url = "jdbc:mysql://localhost:3306/store?useSSL=false&serverTimezone=UTC";10 //MySQL配置时的用户名11 String user = "root";12 //MySQL配置时的密码13 String password = "root";14 //遍历查询结果集15 try {16 //加载驱动程序17  Class.forName(driver);18 //1.getConnection()方法，连接MySQL数据库！！19 con = DriverManager.getConnection(url,user,password);20 if(!con.isClosed())21 System.out.println("Succeeded connecting to the Database!");22 //2.创建statement类对象，用来执行SQL语句！！23 Statement statement = con.createStatement();24 //要执行的SQL语句25 String sql = "select * from goods where Gid=‘g231‘";26 //3.ResultSet类，用来存放获取的结果集！！27 ResultSet rs = statement.executeQuery(sql);28 System.out.println("-----------------");29 System.out.println("执行结果如下所示:"); 30 System.out.println("-----------------"); 31 System.out.println("名称" + "\t" + "数量"); 32 System.out.println("-----------------"); 33 34 String Gname = null;35 String Gnum = null;36 while(rs.next()){37 //获取stuname这列数据38 Gname = rs.getString("Gname");39 //获取stuid这列数据40 Gnum = rs.getString("Gnum");41 42 //输出结果43 System.out.println(Gname + "\t" + Gnum);44  }45  rs.close();46  con.close();47 } catch(ClassNotFoundException e) { 48 //数据库驱动类异常处理49 System.out.println("Sorry,can`t find the Driver!"); 50  e.printStackTrace(); 51 } catch(SQLException e) {52 //数据库连接失败异常处理53  e.printStackTrace(); 54 }catch (Exception e) {55 // TODO: handle exception56  e.printStackTrace();57 }finally{58 System.out.println("数据库数据成功获取！！");59  }60  }61 62 }