Question

我正在编写一个程序，以完成3个任务：

使用ftp。
阅读并处理文件。
从本地文件夹中删除文件。

我使用javax.swing.Timer定期重复。</ p>

我想阻止任务2开始，直到任务1完成，并阻止任务3开始直到任务2完成。

我怎样才能实现

thnks

这是我的代码：

new javax.swing.Timer(TIMER_DELAY, new ActionListener() {
public void actionPerformed(ActionEvent e) {

   FTPFileDownloader ftpdown = new FTPFileDownloader();
   try {
    ftpdown.downloadFiles(Configuration.array.get(0), Configuration.array.get(3), Configuration.array.get(4), Configuration.array.get(5), Configuration.array.get(6));
} catch (IOException e2) {
    // TODO Auto-generated catch block
    e2.printStackTrace();
}

  XmlToDB xmldb=new XmlToDB();   
        ReadFilesFromFolder readfiles=new ReadFilesFromFolder();
        File file=new File("C:\\FTP_CLIENT_DIRECTORY\\");
        ArrayList<File> output=readfiles.listFilesForFolder(file, true, "");
        ArrayList<String> ss = null;
        try {
            ss = xmldb.XMLtoString(output);
            int nbrechang=xmldb.insert(ss);
        } catch (IOException | SAXException | ParserConfigurationException E) {
            // TODO Auto-generated catch block
            E.printStackTrace();
        }


        try {
            FileUtils.cleanDirectory(file);
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } 

            }
      }
  }

 }).start();

Answer 1

很简单，您可以使用单线程执行程序来暂存请求，例如......

ExecutorService executor = Executors.newSingleThreadExecutor();
executor.execute(new Runnable() {
    @Override
    public void run() {
        FTPFileDownloader ftpdown = new FTPFileDownloader();
        try {
            ftpdown.downloadFiles(Configuration.array.get(0), Configuration.array.get(3), Configuration.array.get(4), Configuration.array.get(5), Configuration.array.get(6));
        } catch (IOException e2) {
            // TODO Auto-generated catch block
            e2.printStackTrace();
        }

        XmlToDB xmldb = new XmlToDB();
        ReadFilesFromFolder readfiles = new ReadFilesFromFolder();
        File file = new File("C:\\FTP_CLIENT_DIRECTORY\\");
        ArrayList<File> output = readfiles.listFilesForFolder(file, true, "");
        ArrayList<String> ss = null;
        try {
            ss = xmldb.XMLtoString(output);
            int nbrechang = xmldb.insert(ss);
        } catch (IOException | SAXException | ParserConfigurationException E) {
            // TODO Auto-generated catch block
            E.printStackTrace();
        }

        try {
            FileUtils.cleanDirectory(file);
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

    }
});

这假设您没有更新基于Swing的用户界面（我无法找到任何证据）

然后，您可以简单地使用java.util.Timer在Executor上安排下载请求，该请求将被执行，直到队列中的所有其他先前任务完成为止

Timer timer = new Timer("Download Timer");
timer.scheduleAtFixedRate(new TimerTask() {
    @Override
    public void run() {
        executor.execute(new DownloadRunnable());
    }
}, 0, TIMER_DELAY);

DownloadRunnable只是Runnable实施的一类

public class DownloadRunnable implements Runnable {

    @Override
    public void run() {
        FTPFileDownloader ftpdown = new FTPFileDownloader();
        try {
            ftpdown.downloadFiles(Configuration.array.get(0), Configuration.array.get(3), Configuration.array.get(4), Configuration.array.get(5), Configuration.array.get(6));
        } catch (IOException e2) {
            // TODO Auto-generated catch block
            e2.printStackTrace();
        }

        XmlToDB xmldb = new XmlToDB();
        ReadFilesFromFolder readfiles = new ReadFilesFromFolder();
        File file = new File("C:\\FTP_CLIENT_DIRECTORY\\");
        ArrayList<File> output = readfiles.listFilesForFolder(file, true, "");
        ArrayList<String> ss = null;
        try {
            ss = xmldb.XMLtoString(output);
            int nbrechang = xmldb.insert(ss);
        } catch (IOException | SAXException | ParserConfigurationException E) {
            // TODO Auto-generated catch block
            E.printStackTrace();
        }

        try {
            FileUtils.cleanDirectory(file);
        } catch (IOException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }

    }
}

如何在javax.swing.Timer中分离任务？

1 个答案: