使用Java ，如何把指定长度的字节写入文件呢，或者说如何从inputStream 中读取指定长度的字节写入outputStream中呢？
Java代码
- /***
- * write inputstream into file according to specified length.
- *
- * @param file
- * @param ins
- * : not closed
- * @param length2
- * @throws IOException
- */
- public static FileOutputStream writeInputStream2File(File file,
- InputStream ins, long length2, boolean isCloseOutputStream)
- throws IOException {
- String parentDir = SystemHWUtil.getParentDir(file.getAbsolutePath());
- File fatherFile = new File(parentDir);
- if (!fatherFile.exists()) {
- fatherFile.mkdirs();
- }
- FileOutputStream outs = new FileOutputStream(file);
- int readSize;
- byte[] bytes = null;
- bytes = new byte[(int) length2];
- long length_tmp = length2;
- while ((readSize = ins.read(bytes)) != SystemHWUtil.NEGATIVE_ONE/*-1*/) {
- length_tmp -= readSize;
- outs.write(bytes, 0, readSize);
- if (length_tmp == 0) {
- break;
- }
- //非常重要，千万不能去掉!!!
- if (length_tmp < SystemHWUtil.BUFF_SIZE/*4096*/) {
- bytes = new byte[(int) length_tmp];
- }
- }
- outs.flush();
- if (isCloseOutputStream) {
- outs.close();
- }
- return outs;
- }
- /***
- * Not responsible for closing the output and input stream 写入指定长度的字节到输出流
- *
- * @param fin
- * @param fout
- * : The divided file
- * @param length2
- * @throws IOException
- */
- public static void writeFromFile2File(InputStream fin, OutputStream fout,
- long length2) throws IOException {
- if (length2 == 0) {// want to write zero bytes
- // if (fout != null) {
- // fout.close();
- // }
- return;
- }
- int readSize;
- byte[] bytes = null;
- if (length2 >= SystemHWUtil.BUFF_SIZE) {
- bytes = new byte[SystemHWUtil.BUFF_SIZE];
- } else {
- bytes = new byte[(int) length2];
- }
- long length_tmp = length2;
- while ((readSize = fin.read(bytes)) != SystemHWUtil.NEGATIVE_ONE) {
- length_tmp -= readSize;
- fout.write(bytes, 0, readSize);
- if (length_tmp == 0) {
- break;
- }
- //非常重要，千万不能删除
- if (length_tmp < SystemHWUtil.BUFF_SIZE) {
- bytes = new byte[(int) length_tmp];
- }
- }
- }
- /***
- * Responsible for closing the output stream
- *
- * @param fin
- * @param outPutFile
- * @param length2
- * :The number of bytes to be written
- * @param append
- * : Whether additional
- * @throws IOException
- */
- public static void writeFromFile2File(FileInputStream fin, File outPutFile,
- long length2, boolean append) throws IOException {
- if (length2 == 0) {// want to write zero bytes
- return;
- }
- FileOutputStream fout = null;
- try {
- fout = new FileOutputStream(outPutFile, append/* 追加 */);
- } catch (FileNotFoundException e1) {
- e1.printStackTrace();
- }
- try {
- writeFromFile2File(fin, fout, length2);
- } catch (IOException e) {
- e.printStackTrace();
- } finally {
- fout.flush();
- fout.close();// Close the stream
- }
- }
上述代码见附件中io0007-find_progess\src\main\java\com\io\hw\file\util\FileUtils.java
依赖的包：is_chinese-0.0.2-SNAPSHOT.jar
参考：http://hw1287789687.iteye.com/blog/2023095
写入文件:
Java代码
- /***
- * 写入文件
- * @param content
- * @param charset
- * @param readAndWriteResult
- * @param file
- * @throws IOException
- */
- private static void writeStubFile(String content, String charset, File file) throws IOException {
- FileWriterWithEncoding fileW = new FileWriterWithEncoding(file, charset);
- fileW.write(content);
- fileW.close();
- }
