我是Java servlet的新手，我的问题是：我可以在Servlet中使用dataBaseHandler和conn变量作为全局变量吗？这会带来什么负面影响？
public class AddTrailerServlet extends HttpServlet {
private Connection conn;
private DataBaseHandler dataBaseHandler;
doGet {
dataBaseHandler = new DataBaseHandler();
}
doPost {
dataBaseHandler = new DataBaseHandler();
}
}
您可以创建一个util类，该类返回数据库连接：
public class DataBaseHandler
{
public static Connection getConnection()
{
try
{
Class.forName(driver);
return DriverManager.getConnection(url + dbName,username,password);
} catch (Exception e)
{
System.err.println(e);
//Or your logic to handle exception
}
}
}
您的代码如下：
public class AddTrailerServlet extends HttpServlet
{
doGet()
{
try(Connection conn = DataBaseHandler.getConnection())
{
//Your custom code
}
}
doPost()
{
try(Connection conn = DataBaseHandler.getConnection())
{
//Your custom code
}
}
}