java中用户名与密码和数据库连接的两种方式

方法一String users=username.getText();
     String psw=String.valueOf(password.getPassword());
     /**
      * 连接数据库
      */
     Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
     con = DriverManager
     .getConnection(
       "jdbc:microsoft:sqlserver://192.168.16.48:1433;DatabaseName=prise",
       "sa", "sa");
     stm = con.createStatement();
     String sql = "select * from users where username='"+users+"'" ;
     rs = stm.executeQuery(sql);// 执行给定的sql语句，返回resultset对象
     /**
      * 判断
      */
     int i=0;
     while (rs.next()) {
      i++;      
      if(psw.equals(rs.getString("password"))){
       System.out.println("存在此用户，用户名和密码分别是：");
       System.out.println(rs.getString("username") + "/t"+ rs.getString("password"));
       break;
      }
      if(!psw.equals(rs.getString("password"))){
       System.out.println("密码错误，请重新输入");
       break;
      }
     }
     if(i==0){
      System.out.println("没有此用户");
     }

方法二：

Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
     con = DriverManager
     .getConnection(
       "jdbc:microsoft:sqlserver://192.168.16.48:1433;DatabaseName=prise",
       "sa", "sa");
     stm = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_UPDATABLE);
     String sql="select * from users";
     rs = stm.executeQuery(sql);// 执行给定的sql语句，返回resultset对象
     /**
      * 判断
      */
     
     while (rs.next()) {
           
      if(user.equals(rs.getString("username"))&&psw.equals(rs.getString("password"))){
       System.out.println("存在此用户，用户名和密码分别是：");
       System.out.println(rs.getString("username") + "/t"+ rs.getString("password"));
       break;
      }
      if(user.equals(rs.getString("username"))&&!psw.equals(rs.getString("password"))){
       System.out.println("密码错误，请重新输入");
       break;
      }
     }
     if(rs.isAfterLast()){
      System.out.println("没有此用户请注册");
     }