Java读写TXT文本

public String readTxtFile(String filePath) {
		StringBuffer appInfolistInput = new StringBuffer();
		try {
			String encoding = "UTF8";
			File file = new File(filePath);
			if (file.isFile() && file.exists()) {
				InputStreamReader read = new InputStreamReader(
						new FileInputStream(file), encoding);
				BufferedReader bufferedReader = new BufferedReader(read);
				String lineTxt = null;
				while ((lineTxt = bufferedReader.readLine()) != null) {
					appInfolistInput.append(lineTxt);
				}
				read.close();
				bufferedReader.close();
			} else {
				System.out.println("找不到指定的文件");
			}
		} catch (Exception e) {
			System.out.println("读取文件内容出错");
			e.printStackTrace();
		}
		return appInfolistInput.toString();
	}

public void readByte(String fileName) {
		InputStream is = null;
		try {
			is = new FileInputStream(fileName);
			byte[] byteBuffer = new byte[is.available()];
			int read = 0;
			while((read = is.read(byteBuffer)) != -1){
				System.out.write(byteBuffer, 0, read);
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			try {
				if(is != null){
					is.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

public void writeBuffer(String fileName){
		try {
			File file = new File(fileName);
			BufferedWriter output = new BufferedWriter(new FileWriter(file));
			output.write("hello wrold");
			output.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

public void writeByte(String fileName){
		try {
			File file = new File(fileName);
			OutputStream os = new FileOutputStream(file);
			String s = "hello world";
			byte[] byteBuffer = s.getBytes();
			os.write(byteBuffer, 0, byteBuffer.length);
			os.flush();
			os.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}