Java sql ResultSet没有数据

Question

我想用java从我的sql数据库中提取唯一的一个数据。我尝试使用 resultSet，但是当我想将第一行提取到 int 变量中时，它说 resultSet 没有内容。

这是我的代码

try {

            statement = connexion.createStatement();
            statementArtist = connexion.createStatement();
            String artist = "Mac Miller";
            ResultSet resultat = statement.executeQuery("USE albums SELECT Album.numero_artist FROM Album INNER JOIN Artist ON Album.num_artist = Artiste.num_artist where name like '"+artist+"'");    
            int result = resultat.getInt(1); // Here is the problem
            String query = "USE albums INSERT INTO dbo.Album(Album.num_artist, title, price, genre, date, home, image) VALUES("
                    + result
                    + ", '"
                    + title
                    + "', "
                    + price
                    + ", '"
                    + genre
                    + "', '"
                    + date
                    + "', '"
                    + home
                    + "', '"
                    + image
                    + "')";
            statement.executeUpdate(query);

Answer 1

您应该在结果集上调用 next() 方法来“移动”迭代器:

...
ResultSet resultat = statement.executeQuery("USE albums SELECT Album.numero_artist FROM Album INNER JOIN Artist ON Album.num_artist = Artiste.num_artist where name like '"+artist+"'");    
resultat.next();           
int result = resultat.getInt(1); // Here is the problem
...

如果安全性和更好的性能对您的应用程序很重要，您还应该考虑使用准备好的语句。