copyBigDataToSD

private void copyBigDataToSD(String strOutFileName) {
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)
            != PackageManager.PERMISSION_GRANTED) {
        //申请WRITE_EXTERNAL_STORAGE权限
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE},
                1);
    }
    InputStream myInput = null;
    OutputStream myOutput = null;
    File myDir = new File(strOutFileName);
    myDir.mkdirs();
    File file = new File(myDir, "out.json");
    if (file.exists()) {
        file.delete();
    }
    try {
        file.createNewFile();

        myOutput = new FileOutputStream(file);
        myInput = this.getAssets().open("plants.json");

        byte[] buffer = new byte[1024];
        int length = myInput.read(buffer);
        while (length > 0) {
            myOutput.write(buffer, 0, length);
            length = myInput.read(buffer);
        }
        myOutput.flush();
        myInput.close();
        myOutput.close();

    } catch (IOException e) {
        e.printStackTrace();
    }
}