Java和SQL Server

我是java新手，我正在尝试创建一个方法，该方法将根据传递给数据库的查询从数据库中检索信息

我认为我可以通过创建以下类型的对象来创建方法：

private Connection controlTableConnection = null;

然后

Statement statement = controlTableConnection.createStatement();

但当我执行这段代码时，我会得到一个突出显示错误： 未处理的异常

如有任何帮助，将不胜感激

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class ConnectMSSQLServer {

    private static final String db_connect_string = "jdbc:sqlserver://Cdsx\\SQxxs";
    private static final String db_userid = "aa";
    private static final String db_password = "bb";
    private Connection controlTableConnection = null;


    public void dbConnect() {
        try {
            Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            Connection controlTableConnection = DriverManager.getConnection(db_connect_string, db_userid, db_password);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void dbDisconnect() {
        try {
            if (controlTableConnection != null && !controlTableConnection.isClosed()) {
                controlTableConnection.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void createstatement() {

        Statement statement = controlTableConnection.createStatement();
    }


}

---

您必须像下面那样包装createStatement行，因为您必须处理SQLException

    try {
        Statement statement = controlTableConnection.createStatement();
    } catch (SQLException e) {
        e.printStackTrace();
    }

---

连接不是空的吗？在类路径上有驱动程序吗？默认端口是否正确？sql server是否处于活动状态？你到底得到了什么样的例外情况？ 您至少需要发布堆栈跟踪或日志