我试图让用户将我的 servlet 中的数据保存为 CSV 文件。最初我只是找到他们的桌面来放置文件，但此路线的权限会被拒绝，所以我想询问用户他们想要将文件保存在哪里。
据我所知，我无法在 servlet 中使用 Swing API，因为 Tomcat 不知道如何绘制 GUI。我尝试了这段代码:
String fileName = "ClassMonitor" + formatter.format(currentDate) + ".csv";
File csvFile = new File(fileName);
//Attempt to write as a CSV file
try{
JFileChooser fileChooser = new JFileChooser();
fileChooser.setSelectedFile(csvFile);
int returnValue = fileChooser.showSaveDialog(null);
if(returnValue == JFileChooser.APPROVE_OPTION)
{
BufferedWriter out = new BufferedWriter(new FileWriter(csvFile));
//Iterates and writes to file
for(ClassInfo classes : csvWrite)
{
//Check if the class has a comma. Currently, only section titles have a comma in them, so that's all we check for.
classes.setSectionTitle(replaceComma(classes.getSectionTitle()));
out.write(classes.toString());
}
//Close the connection
out.close();
}
//Log the process as successful.
logger.info("File was successfully written as a CSV file to the desktop at " + new Date() + "\nFilename" +
"stored as " + fileName + ".");
}
catch(FileNotFoundException ex)
{
//Note the exception
logger.error("ERROR: I/O exception has occurred when an attempt was made to write results as a CSV file at " + new Date());
}
catch(IOException ex)
{
//Note the exception
logger.error("ERROR: Permission was denied to desktop. FileNotFoundException thrown.");
}
catch(Exception ex)
{
//Note the exception
logger.error("ERROR: Save file was not successfull. Ex: " + ex.getMessage());
}
}
但这会抛出 headlessException。
任何关于如何在 servlet 中实现诸如保存文件对话框之类的内容的指导将不胜感激。
最佳答案
只需将其写入响应正文而不是本地(!!)磁盘文件系统。
response.setContentType("text/csv"); // Tell browser what content type the response body represents, so that it can associate it with e.g. MS Excel, if necessary.
response.setHeader("Content-Disposition", "attachment; filename=name.csv"); // Force "Save As" dialogue.
response.getWriter().write(csvAsString); // Write CSV file to response. This will be saved in the location specified by the user.
Content-Disposition:attachment header 负责另存为魔法。
另请参阅:
关于java - 如何从 servlet 使用保存文件对话框？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/15483637/