java - SQL 功能不支持异常

Question

我不断收到功能不支持的异常，代码如下:

public Collection<Product> getProds(String col, String prod) {
    LinkedList<Product> list = new LinkedList<>();
    try {
        String query = "SELECT * FROM Product where ? LIKE ?";
        PreparedStatement ps = con.prepareStatement(query);
        ps.setString(1, col);
        ps.setString(1, prod);
        ResultSet rs = ps.executeQuery(query);
        while ( rs.next() ) {
            Product product = new Product(
                    rs.getString("PID"),
                    rs.getString("Artist"),
                    rs.getString("Title"),
                    rs.getString("Description"),
                    rs.getInt("price"),
                    rs.getString("thumbnail"),
                    rs.getString("fullimage")
            );
            list.add( product );
        }
        return list;
    }
    catch(Exception e) {
        System.out.println( "Exception in getProducts(): " + e );
        return null;
    }
}

我猜它与executeQuery 有关。非常感谢任何帮助

Answer 1

不能使用PreparedStatement的setString方法设置列名，只能设置参数。

如果不知道列名，可以在创建PreparedStatement之前使用Java String的replace方法指定列名，例如:

String query = "SELECT * FROM Product where <column> LIKE ?";
query = query.replaceAll("<column>", col);

PreparedStatement ps = con.prepareStatement(query);
ps.setString(1, prod);
ResultSet rs = ps.executeQuery();