编写大文件Android时出现OutofMemory错误

Question

I'm trying to encrypt a large file which is 500MB but my code throws an out of memory error, for small files below 50MB the code works fine. Im using a third party library called JNCryptor for encryption, please have a look at my code and correct me if any mistake. Thanks in advance.

public void encrypt() {
    String file = Environment.getExternalStorageDirectory() + "/sai/ravi_enc.exe";
    byte[] filedata = null;
    try {
        filedata = IOUtils.toByteArray(new FileInputStream(file));
    } catch (IOException e) {
        e.printStackTrace();
    }

    JNCryptor cryptor = new AES256JNCryptor();
    String password = "123456789";

    try {
        byte[] ciphertext = cryptor.decryptData(filedata, password.toCharArray());
        String Outfile = Environment.getExternalStorageDirectory() + "/sai/ravi_dec.exe";
        writeFile(ciphertext, Outfile);
        System.out.println("Done");
    } catch (CryptorException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public void writeFile(byte[] data, String fileName) throws IOException {
    FileOutputStream out = new FileOutputStream(fileName);
    out.write(data);
    out.close();
}

Answer 1

This is up to JNCryptor to well manage memory, especially if it uses temp buffer. It is better to work on streams instead of buffers. Just for testing, if you write directly the fileData to your outFile, do you get OutOfMemoryError?

writeFile(filedata, Outfile);