數據庫是MySQL，控制臺沒報錯，輸出結果“數據庫連接異常！”

package?util;

import?java.sql.Connection;
import?java.sql.DriverManager;
import?java.sql.SQLException;

public?class?DBHelper?{
????
????private?static?final?String?driver?=?"com.mysql.jdbc.Driver";//數據庫驅動
????//連接數據庫的URL地址
????private?static?final?String?url?=?"jdbc:mysql://localhost:3306/test"?;
????private?static?final?String?uesrname?=?"root";
????private?static?final?String?password?="root";
????//靜態代碼塊負責加載驅動
????private?static?Connection?conn?=?null;
????static
????{
????????try?{
????????????Class.forName(driver);
????????????
????????}?catch?(Exception?e)?{
????????????System.out.println("找不到驅動程序類?，加載驅動失?。?);
????????????e.printStackTrace();
????????}
????}
????
????//單例模式返回數據庫連接對象
????public?static?Connection?getConnection()?throws?Exception{
????????if(conn?==?null){
????????????DriverManager.getConnection(url,?uesrname,?password);
????????????return?conn;
????????}
????????return?conn;
????}
????
????public?static?void?main(String[]?args)?{
????????try?{
????????????Connection?conn?=?DBHelper.getConnection();
????????????if(conn?!=null){
????????????????System.out.println("數據庫連接正常");
????????????}else{
????????????????System.out.println("數據庫連接異常！");
????????????}
????????}?catch?(Exception?e)?{
????????????e.printStackTrace();
????????}
????????
????}
}

請把錯誤信息貼出來，還有你使用的數據庫是什么。這樣有助于我們解答問題。