1. 需要文件转换成字节数组。

2. 将字节数组转换成字符串，不过需要注意的是需要将字节数组使用Base64加密，这样防止传输过程中因为编码问题导致文件损坏的问题。

3. 接收方将字符串转化成字节数组，再使用Base64解密，再输出到文件就OK了。

下面贴上代码：

/**

* summary:将字符串存储为文件 采用Base64解码

* @param fileStr

* @param outfile

*

*/

public static void streamSaveAsFile(InputStream is, String outFileStr) {

FileOutputStream fos = null;

try {

File file = new File(outFileStr);

BASE64Decoder decoder = new BASE64Decoder();

fos = new FileOutputStream(file);

byte[] buffer = decoder.decodeBuffer(is);

fos.write(buffer, 0, buffer.length);

} catch (Exception e) {

e.printStackTrace();

throw new RuntimeException(e);

} finally {

try {

is.close();

fos.close();

} catch (Exception e2) {

e2.printStackTrace();

throw new RuntimeException(e2);

}

}

}

/**

*

*

* summary:将字符串存储为文件

* @param fileStr

* @param outfile

*

*/

public static void stringSaveAsFile(String fileStr, String outFilePath) {

InputStream out = new ByteArrayInputStream(fileStr.getBytes());

FileStrUtil.streamSaveAsFile(out, outFilePath);

}

/**

* 将流转换成字符串 使用Base64加密

*

* @param in输入流

* @return

* @throws IOException

*/

public static String streamToString(InputStream inputStream) throws IOException {

byte[] bt = toByteArray(inputStream);

inputStream.close();

String out = new sun.misc.BASE64Encoder().encodeBuffer(bt);

return out;

}

/**

* 将流转换成字符串

*

* @param in输入流

* @return

* @throws IOException

*/

public static String fileToString(String filePath) throws IOException {

File file = new File(filePath);

FileInputStream is = new FileInputStream(file);

String fileStr = FileStrUtil.streamToString(is);

return fileStr;

}

/**

*

* summary:将流转化为字节数组

* @param inputStream

* @return

* @throws IOException

*

*/

public static byte[] toByteArray(InputStream inputStream) throws IOException {

ByteArrayOutputStream out = new ByteArrayOutputStream();

byte[] buffer = new byte[1024 * 4];

byte[] result = null;

try {

int n = 0;

while ((n = inputStream.read(buffer)) != -1) {

out.write(buffer, 0, n);

}

result = out.toByteArray();

} catch (Exception e) {

e.printStackTrace();

throw new RuntimeException(e);

} finally {

out.close();

}

return result;

}

public static void main(String[] args) throws Exception {

String fromPath = "F:\\fileupload\\aaa.docx";

String toPath = "C:\\Users\\Desktop\\aaaa.docx";

String fileStr = FileStrUtil.fileToString(fromPath);

FileStrUtil.stringSaveAsFile(fileStr, toPath);

}