英文:
Custom cell button action to Download a file to the 'downloads' folder
问题
以下是翻译好的部分：
我已经成功构建了一个自定义单元格，其中包含一个按钮，用于从我的本地数据库中下载文件。不知何故，一切似乎都很正常，但当我运行并尝试下载时，出现了一个 SQL 错误，表示我的 SQL 查询存在问题。我还希望用户能够选择保存下载文件的位置。非常感谢任何帮助。
以下是 SQL 错误信息：
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 在你的 SQL 语法中有一个错误；请检查与你的 MySQL 服务器版本对应的手册，了解在第 1 行附近使用的正确语法。
以下是下载按钮的 onAction 方法：
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);
英文:
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);
答案1
得分: 0
以下是翻译好的内容：
这是对我有效的做法：
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));
英文:
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));
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