将文件下载到“下载”文件夹的自定义单元格按钮操作

Question

so I have managed to build my custom cell which holds a button to download a file from my local database. somehow all seems fine but when i run and try to download, I get an sql error that there's a problem with my sql query. I would also like the user to chose the location to save the downloaded file. Any help is highly appreciated.

here is the sql error:

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '='20'' at line 1

here is the onaction method for the download button

FileDownloadButton.setOnAction(e -> {

                                    Item chosenItem = getTableView().getItems().get(getIndex());
                                    File file = new File(chosenItem.getPaperName());
                                    try {
                                        String filequery = "Select File from items Where" + "itemID" + " = " + chosenItem.getId();
                                        PreparedStatement pst = connection.prepareStatement(filequery);
                                        ResultSet rs = pst.executeQuery();

                                        FileOutputStream fileout = new FileOutputStream(file);
                                        while (rs.next()) {
                                            InputStream fileinput = result.getBinaryStream("file");
                                            byte[] buffer = new byte[1024];
                                            while (fileinput.read(buffer) > 0) {
                                                fileout.write(buffer);

Answer 1

Here is what has worked for me

FileDownloadButton.setOnAction(e -> {
                                    Item chosenItem = getTableView().getItems().get(getIndex());
                                    byte[] buffer = new byte[1024];
                                    String filename = null;

                                    try {

                                        String filequery = "Select File from items Where itemID = " + chosenItem.getId();
                                        PreparedStatement pst = connection.prepareStatement(filequery);

                                        ResultSet rs = pst.executeQuery();

                                        if (rs.next()) {
                                            try {
                                                InputStream fileIn = rs.getBinaryStream("File");

                                                buffer = rs.getBytes("File");
                                                filename = chosenItem.getPaperName();
                                                FileOutputStream fileout = new FileOutputStream("D:/Downloads/" + filename);
                                                while (fileIn.read(buffer) > 0) {
                                                    fileout.write(buffer);
                                                }
                                            } catch (FileNotFoundException ex) {
                                                /*...*/
                                            }

                                        }
                                        /*finally open the file*/
                                        Desktop.getDesktop().open(new File("D:/Downloads/" + filename));