Java字符串与文件的转换

Java中有时候需要读取一个文本类的文件，将其转换为字符串，然后做进一步处理。Java中没有现成的API方法，自己手动实现一个，大家来分享。

??? 一、字符串转换为文件

??????? /**
???????? * 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));
??????????????????????? char buf[] = new char[1024];???????? //字符缓冲区
??????????????????????? int len;
??????????????????????? while ((len = bufferedReader.read(buf)) != -1) {
??????????????????????????????? bufferedWriter.write(buf, 0, len);
??????????????????????? }
??????????????????????? 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;
??????? }

??? 二、文件转换为字符串

??????? /**
???????? * 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;
??????? }

??? 不想抛出太多的检查异常，如果你需要捕捉，就抛出吧。

??? 注意：对于文件转换为字符串，存在一个编码问题。上面的file2String方法中，如果你不知道编码，调用时候方法设为null即可，此时使用系统默认的编码类型。

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