[移动开发]Android studio 自带的 LoginActivity 连接MySQL 实现登录功能

public static void queryLogin(String username, String ppwd){
        try{
            Class.forName(driver);
            System.out.println("驱动加载失败！");
        }catch (Exception e){
            System.out.println(e.getMessage());
        }
        try{
            conn = DriverManager.getConnection(url,user,pwd);
            System.out.println("数据库连接成功！！");
        }catch (Exception e){
            System.out.println(e.getMessage());
        }
        try{
            String sql = "select * from user where username='" + username + "' and password='"+ppwd+"'";
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            System.out.println(username+ppwd);
            if (rs.next()){
                checkConnection = 1;
                name = rs.getString("username");
                newPwd = rs.getString("password");
                System.out.print(newPwd);
            }else{
                checkConnection = -1;
            }
            System.out.println(checkConnection);
            rs.close();
            ps.close();
        }catch (Exception e){
            System.out.println(e.getMessage());
        }
        System.out.println("数据库连接"+name+newPwd);
        if (conn != null){
            try{
                conn.close();
            }catch (Exception e){
                System.out.println(e.getMessage());
            }
        }
    }