java.sql.SQLException:参数索引超出范围(1>参数个数,为0).使用PreparedStatement时

Question

在Java/MariaDb中使用preparedStatement,如下面的函数所示

public ArrayList<String> findPath(String roomName) throws SQLException, IOException, InstantiationException, IllegalAccessException, ClassNotFoundException
{
    ArrayList<String> path = new ArrayList<String>(); 
    connection = getConnection();
    String queryPattern = "SELECT `Livello_1`, `Livello_2`, `Livello_3`, `Livello_4` FROM Camera WHERE Camera.Nome = '?'";
    PreparedStatement queryStatement = connection.prepareStatement(queryPattern);
    queryStatement.setString(1, roomName);
    ResultSet rs = queryStatement.executeQuery();
    if(rs.next())
    {
        for(int i = 0; i < 3; i++)
        {
            path.add(rs.getString(i));
        }
    }
    return path;
}

我收到错误消息:

java.sql.SQLException:参数索引超出范围(1>参数个数,为0).

并且错误行号指向行

queryStatement.setString(1, roomName);

Answer 1

正如评论中提到的，您应该删除 ? 中的引号。

另外， 中rs.getString(i),i应为正值。循环从1开始计数。

总结一下：

public ArrayList<String> findPath(String roomName) throws SQLException, IOException, InstantiationException, IllegalAccessException, ClassNotFoundException
{
    ArrayList<String> path = new ArrayList<String>(); 
    connection = getConnection();
    String queryPattern = "SELECT Livello_1, Livello_2, Livello_3, Livello_4 FROM Camera WHERE Camera.Nome = ?";
    PreparedStatement queryStatement = connection.prepareStatement(queryPattern);
    queryStatement.setString(1, roomName);
    ResultSet rs = queryStatement.executeQuery();
    if(rs.next())
    {
        for(int i = 1; i < 4; i++)
        {
            path.add(rs.getString(i));
        }
    }
    return path;
}