获取文件流的几个工具函数

1 合并两个字节数组

public static byte[] mergeBytes(byte[] data1, byte[] data2) {
    byte[] data3 = new byte[data1.length + data2.length];
    System.arraycopy(data1, 0, data3, 0, data1.length);
    System.arraycopy(data2, 0, data3, data1.length, data2.length);
    return data3;
}
2 字节数组写入文件

public static void writeBytesToFile(byte[] bs,String path) throws IOException {

    OutputStream out = new FileOutputStream(path);
    InputStream is = new ByteArrayInputStream(bs);
    byte[] buff = new byte[1024];
    int len = 0;
    while ((len = is.read(buff)) != -1) {
        out.write(buff, 0, len);
    }
    is.close();
    out.close();
}
3 文件转成byte字节数组。

private byte[] fileConvertToByteArray(File file) {
    byte[] data = null;

    try {
        FileInputStream fis = new FileInputStream(file);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        int len;
        byte[] buffer = new byte[1024];
        while ((len = fis.read(buffer)) != -1) {
            baos.write(buffer, 0, len);
        }
        data = baos.toByteArray();

        fis.close();
        baos.close();
    } catch (Exception e) {
        e.printStackTrace();
    }

    return data;
}