import java.io.*;class  UnionDemo{	public static void main(String[] args) 	{		String srcFilePath = "D:\\Work\\";		String tarFilePath = "D:\\Test\\";		File srcFile = new File(srcFilePath);		File tarFile = new File(tarFilePath);		BufferedWriter bw=null;		try		{			if(tarFile.isDirectory())				tarFile.mkdir();			else				tarFile.createNewFile();		    bw = new BufferedWriter(new FileWriter(new File(tarFile,"union.txt")));		}		catch (IOException ex)		{		}		unionFile(srcFile,bw);	}	public static void unionFile(File srcFile,BufferedWriter bw)	{		try		{			File[]files = srcFile.listFiles();			for(File temFile : files)			{				if(temFile.isDirectory())					unionFile(srcFile,bw);				else				{					BufferedReader br = new BufferedReader(new FileReader(temFile));					String line = null;					while((line = br.readLine()) != null)						bw.write(line);					if(br != null)br.close();					if(bw != null)bw.close();				}			}		}		catch (IOException ex)		{		}			}}