java读写txt文件

File rfile = new File("F:\\books\\cluster3.txt");
BufferedReader rbr = new BufferedReader(new FileReader(rfile));
while((tmp=rbr.readLine())!=null ){
        System.out.println(tmp);
			}

File wfile = new File("F:\\books\\book.txt");
BufferedWriter wbr = new BufferedWriter(new FileWriter(wfile,true));
while((tmp=rbr.readLine())!=null){
        wbr.write("Hello World!");
	wbr.newLine();
	wbr.flush();
	}