public class asd {
	private static void customBufferStreamCopy(String source, String target) {  
		
	    InputStream fis = null;  
	    OutputStream fos = null;  
	    try {  
	        fis = new FileInputStream(source);  
	        fos = new FileOutputStream(target);  
	        byte[] buf = new byte[4096];  
	        int i;  
	        while ((i = fis.read(buf)) != -1) {  
	            fos.write(buf, 0, i);  
	        }  
	    }  
	    catch (Exception e) {  
	        e.printStackTrace();  }
	    finally {
			try {
				fis.close();
				fos.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
		}
	    
	}
public static void main(String[] args) {
	
	File f=new File("C:/Users/Administrator/Desktop/biji4.txt");
	if(f.exists()){}
	else {
		try {
			f.createNewFile();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	new asd();
	asd.customBufferStreamCopy("C:/Users/Administrator/Desktop/biji4.txt", "C:/Users/Administrator/Desktop/biji3.txt");
	}
}
原文:http://www.cnblogs.com/zhaosong-0102/p/7375331.html