Java中String与File的互相转换

Posted 2021-06-27 李昊轩的博客

今天有这个需求, 记了下来, 算是搬运, 但是也发现了源码的一些缺陷, 遂记载一下结果

字符串转文件

	/**
     * 将字符串写入指定文件(当指定的父路径中文件夹不存在时，会最大限度去创建，以保证保存成功！)
     *
     * @param res      原字符串
     * @param filePath 文件路径
     * @return 成功标记
     */
	public static boolean string2File(String res, String filePath) {
        boolean flag = true;
        BufferedReader bufferedReader = null;
        BufferedWriter bufferedWriter = null;
        try {
            File distFile = new File(filePath);
            if (!distFile.getParentFile().exists()) distFile.getParentFile().mkdirs();
            bufferedReader = new BufferedReader(new StringReader(res));
            bufferedWriter = new BufferedWriter(new FileWriter(distFile));
            String len;
            while ((len = bufferedReader.readLine()) != null) {
                // 这里因为 单引号 ' 有些问题, 做了下面特殊处理
                len = len.replace("'", "'");
                bufferedWriter.write(len);
                bufferedWriter.newLine();
            }
            bufferedWriter.flush();
            bufferedReader.close();
            bufferedWriter.close();
        } catch (IOException e) {
            e.printStackTrace();
            flag = false;
            return flag;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return flag;
    }

文件转字符串

		/** 
         * 文本文件转换为指定编码的字符串 
         * 
         * @param file         文本文件 
         * @param encoding 编码类型 
         * @return 转换后的字符串 
         * @throws IOException 
         */ 
        public static String file2String(File file, String encoding) { 
                InputStreamReader reader = null; 
                StringWriter writer = new StringWriter(); 
                try { 
                        if (encoding == null || "".equals(encoding.trim())) { 
                                reader = new InputStreamReader(new FileInputStream(file), encoding); 
                        } else { 
                                reader = new InputStreamReader(new FileInputStream(file)); 
                        } 
                        //将输入流写入输出流 
                        char[] buffer = new char[DEFAULT_BUFFER_SIZE]; 
                        int n = 0; 
                        while (-1 != (n = reader.read(buffer))) { 
                                writer.write(buffer, 0, n); 
                        } 
                } catch (Exception e) { 
                        e.printStackTrace(); 
                        return null; 
                } finally { 
                        if (reader != null) 
                                try { 
                                        reader.close(); 
                                } catch (IOException e) { 
                                        e.printStackTrace(); 
                                } 
                } 
                //返回转换结果 
                if (writer != null) 
                        return writer.toString(); 
                else return null; 
        }

简化版本

  //将file转化成string
    private static String file2String(String filePath) throws IOException {
        //对一串字符进行操作
        StringBuffer fileData = new StringBuffer();
        //
        BufferedReader reader = new BufferedReader(new FileReader(filePath));
        char[] buf = new char[1024];
        int numRead = 0;
        while ((numRead = reader.read(buf)) != -1) {
            String readData = String.valueOf(buf, 0, numRead);
            fileData.append(readData);
        }
        //缓冲区使用完必须关掉
        reader.close();
        return fileData.toString();
    }