@Test
    public  void copy() {
        String str1 = new String("HelloWorld.txt");
        String str2 = new String("HelloWorld2.txt");
        File file1 = new File(str1);
        File file2 = new File(str2);
        FileReader fr = null;
        FileWriter fw = null;
        BufferedReader br = null;
        BufferedWriter bw = null; 
        try {
            fr = new FileReader(file1);
            fw = new FileWriter(file2);
            br = new BufferedReader(fr);
            bw = new BufferedWriter(fw);
            //此方法可以将读取到的数据换行
            /*char[] c = new char[1024];
            int len;
            while((len = br.read(c)) != -1){
                String str = new String(c,0,len);
                bw.write(str);
                
                bw.flush();
            }*/
            //此方法不能将读取到的数据换行
            String str ;
            while((str = br.readLine()) != null){
                bw.write(str);
                System.out.println(str);
                bw.flush();
            }
        } catch (Exception e) {
            // TODO: handle exception
        }finally{
            if(bw != null){
                try {
                    bw.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(br != null){
                try {
                    br.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(fw != null){
                try {
                    fw.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(fr != null){
                try {
                    fr.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
        
    }