public Connection conn=null;
public PreparedStatement pst=null;
public ResultSet rs=null;
String Driver="com.mysql.cj.jdbc.Driver";//注意:該版本為8.0.22
String url="jdbc:mysql://localhost:3306/mydb?serverTimezone=GMT%2B8";//
String user="root";//填你的mysql使用者名稱
String password="ok";//填你的mysql密碼
public void  getConn(){
    try {
        Class.forName(Driver);
        conn= DriverManager.getConnection(url,user,password);
    }catch (Exception e){
        e.printStackTrace();
    }
}
public  void  closeAll(){
    try {
        if (rs!=null){
            rs.close();
        }
        if (pst!=null){
            pst.close();
        }
        if (conn!=null){
            pst.close();
        }
    }catch (Exception e){
        e.printStackTrace();
    }
}
public int update(String sql,Object[]parms){
    getConn();
    try {
        pst=conn.prepareStatement(sql);
        for (int i = 0; i < parms.length; i++) {
            pst.setObject(i+1,parms[i]);
        }
        return pst.executeUpdate();
    }catch (Exception e){
        e.printStackTrace();
    }
    return -1;
}
public  void  select(String sql,Object[]parms){
    getConn();
    try {
        pst=conn.prepareStatement(sql);
        for (int i = 0; i < parms.length; i++) {
            pst.setObject(i+1,parms[i]);
        }
        rs= pst.executeQuery();
    }catch (Exception e){
        e.printStackTrace();
    }
}