java读文件

//很好的方法：读文件
public static String readFileByLines(String fileName) {
        FileInputStream file = null;
        BufferedReader reader = null;
        InputStreamReader inputFileReader = null;
        String content = "";
        String tempString = null;
        try {
            file = new FileInputStream(fileName);
            inputFileReader = new InputStreamReader(file, "utf-8");//utf-8可改为GBK
            reader = new BufferedReader(inputFileReader);
            // 一次读入一行，直到读入null为文件结束
            while ((tempString = reader.readLine()) != null) {
                content += tempString;
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e1) {
                }
            }
        }
        return content;
    }