Question

所以我必须在java中创建一个自动在后台运行并查找新的.dat文件的程序，当它看到新的.dat文件时，它会运行.bat文件将数据加载到数据库中。到目前为止，我有一个程序，可以监视新文件的创建，修改和删除。我还有一个运行.bat文件的脚本并将数据加载到数据库中我现在只需连接两个但我不知道如何去做，如果有人能指出我正确的方向我会非常感激它

以下是我到目前为止的代码。

import static java.nio.file.LinkOption.NOFOLLOW_LINKS;
import static java.nio.file.StandardWatchEventKinds.ENTRY_CREATE;
import static java.nio.file.StandardWatchEventKinds.OVERFLOW;
import static java.nio.file.StandardWatchEventKinds.ENTRY_DELETE;
import static java.nio.file.StandardWatchEventKinds.ENTRY_MODIFY;

import java.io.*;
import java.util.*;
import java.io.File;
import java.io.IOException;
import java.nio.file.FileSystem;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.WatchEvent;
import java.nio.file.WatchEvent.Kind;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;


public class Order_Processing {

    public static void watchDirectoryPath(Path path)
    {
        try {
            Boolean isFolder = (Boolean) Files.getAttribute(path,
                    "basic:isDirectory", NOFOLLOW_LINKS);
            if (!isFolder)
            {
                throw new IllegalArgumentException("Path: " + path
                        + " is not a folder");
            }
        } 
        catch (IOException ioe)
        {
            ioe.printStackTrace();
        }
        System.out.println("Watching path: "+ path);
        FileSystem fs = path.getFileSystem();
        try (WatchService service = fs.newWatchService())
        {
            path.register(service, ENTRY_CREATE, ENTRY_MODIFY, ENTRY_DELETE);
            WatchKey key = null;
            while (true) 
            {
                key = service.take();

                Kind<?> kind = null;
                for (WatchEvent<?> watchEvent : key.pollEvents())
                {
                    kind = watchEvent.kind();
                    if (OVERFLOW == kind)
                    {
                        continue;
                    }
                    else if (ENTRY_CREATE == kind)
                    {
                        Path newPath = ((WatchEvent<Path>) watchEvent)
                                .context();
                        System.out.println("New Path Created: " + newPath);
                    }
                    else if (ENTRY_MODIFY == kind)
                    {
                        Path newPath = ((WatchEvent<Path>) watchEvent)
                                .context();
                        System.out.println("New path modified: "+ newPath);
                    }
                    else if (ENTRY_DELETE == kind)
                    {
                        Path newPath = ((WatchEvent<Path>) watchEvent)
                                .context();
                        System.out.println("New path deleted: "+ newPath);
                    }
                }
                if (!key.reset())
                {
                    break;
                }
            }
        }
        catch (IOException ioe)
        {
            ioe.printStackTrace();
        } 
        catch (InterruptedException ie)
        {
            ie.printStackTrace();
        }
    }

public static void main(String[] args)
                            throws FileNotFoundException
{
    File dir = new File("C:\\Paradigm");
    watchDirectoryPath(dir.toPath());

    //below is the script that runs the .bat file and it works if by itself
    //with out all the other watch code.
    try {
        String[] command = {"cmd.exe", "/C", "Start", "C:\\Try.bat"};
        Process p =  Runtime.getRuntime().exec(command);           
    } 
    catch (IOException ex) {
    }
    }
 }

Answer 1

这不起作用，因为你有while (true)。这是有道理的，因为你正在倾听并希望不断发生;但是，永远不会执行bat调用，因为watchDirectory(...)永远不会终止。要解决这个问题，请将主要部分的其余部分拉出自己的功能，如此

public static void executeBat() {
    try {
        String[] command = {"cmd.exe", "/C", "Start", "C:\\Try.bat"};
        Process p =  Runtime.getRuntime().exec(command);
    }
    catch (IOException ex) {
        // You should do something with this. 
        // DON'T JUST IGNORE FAILURES
    }

这样在创建文件时，您可以调用该bat脚本

...
else if (ENTRY_CREATE == kind)
{
    Path newPath = ((WatchEvent<Path>) watchEvent).context();
    executeBat();
}
...

在文件夹中创建新文件时是否可以运行循环？

1 个答案: