java将txt内容复制到另一个txt

package document;

import interfaces.ICommon;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
* 将txt中的内容复制到另一个txt中
* @author DanielCooger
* <a href="mailto:tangjunfeng52099@gmail.com">daniel</a>
*/

public class Txt implements ICommon{
 private String date = new SimpleDateFormat("yyyyMMddHHmmss")
   .format(new Date());
  //新建txt文件
 private String copy = "D:\\doc\\TXT" + date + ".txt";

 public boolean readText(String file) throws Exception{
   // 创建输入流读取txt文件
  BufferedInputStream br;
  //创建输出流写入文件
  BufferedOutputStream bw;
  FileOutputStream fw;
  try {
   br = new BufferedInputStream(new FileInputStream(file));
   fw = new FileOutputStream(copy);
   bw = new BufferedOutputStream(fw);
   int a;
   //循环写入文本中
   while ((a = br.read()) != -1) {
    bw.write(a);
   }
   bw.close();
   fw.close();
   System.out.println("ok");
   return true;
  } catch (IOException e) {
   throw new Exception("写入文件失败");
  }
 }
}