能解释一下这段代码吗

Question

    User resultUser=null;
    String sql="select * from t_user where userName=? and password=?";
    PreparedStatement pstmt=con.prepareStatement(sql);
    pstmt.setString(1, user.getUserName());
    pstmt.setString(2, user.getPassword());
    ResultSet rs=pstmt.executeQuery();
    if(rs.next()){
        resultUser=new User();
        resultUser.setUserId(Integer.parseInt(rs.getString("userId")));
        resultUser.setUserName(rs.getString("userName"));
        resultUser.setPassword(rs.getString("password"));
        resultUser.setRole(Integer.parseInt(rs.getString("role")));
    }
    return resultUser;
}

Answer 1

执行sql查询语句，参数username和password， if(rs.next()){判断是否有数据，有把查询的结果设置到resultUser=new User(); 返回 resultUser