读写文件方法

 try {
			// 方法一
			BufferedReader br = new BufferedReader(new FileReader(new File(
					"D:\\1.xls")));
			// StringBuilder bd = new StringBuilder();
			StringBuffer bd = new StringBuffer();
			while (true) {
				String str = br.readLine();
				if (str == null) {
					break;
				}
				System.out.println(str);
				bd.append(str);
			}

			br.close();
			// System.out.println(bd.toString());

			// 方法二
			InputStream is = new FileInputStream(new File("d:\\1.xls"));
			byte b[] = new byte[Integer.parseInt(new File("d:\\1.xls").length()
					+ "")];
			is.read(b);
			System.out.write(b);
			System.out.println();
			is.close();

			// 方法三
			Reader r = new FileReader(new File("d:\\1.xls"));
			char c[] = new char[(int) new File("d:\\1.xls").length()];
			r.read(c);
			String str = new String(c);
			System.out.print(str);
			r.close();

		} catch (RuntimeException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

 

try {
            PrintWriter pw = new PrintWriter(new FileWriter("d:\\1.txt"));
            BufferedWriter bw = new BufferedWriter(new FileWriter(new File(
                    "d:\\1.txt")));
            OutputStream os = new FileOutputStream(new File("d:\\1.txt"));
            // 1
            os.write("ffff".getBytes());
            // 2
            // bw.write("ddddddddddddddddddddddddd");
            // 3
            // pw.print("你好sssssssssssss");
 
            bw.close();
            pw.close();
            os.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

 

public static void main(String[] args) throws Exception {
		BufferedWriter bw = new BufferedWriter(new FileWriter("D:\\test.txt"));
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String s;
		while((s=br.readLine())!=null){
			System.out.println("he:"+s);
			bw.write(s);
			bw.newLine();
			bw.flush();
		}
	}