JAVA流操作

file 转 数组，方法一：

        File file = new File("D:\\111.pdf");
        // File 转数组
        FileInputStream fis = new FileInputStream(file);
        ByteArrayOutputStream bos = new ByteArrayOutputStream(1000);
        byte[] b = new byte[1000];
        int n;
        while ((n = fis.read(b)) != -1) {
            bos.write(b, 0, n);
        }
        fis.close();
        byte[] bytes = bos.toByteArray();
        System.out.println(bytes);
        bos.close();

file 转 数组，方法二：

        File file = new File("D:\\111.pdf");
        FileInputStream fis = new FileInputStream(file);
        byte[] bytes = IoUtil.readBytes(fis, true);

字节流转文件，方法一：

    /**
     * 将字节流转换成文件
     * @param filename
     * @param data
     * @throws Exception
     */
    public static void saveFile(String filename,byte [] data)throws Exception{
        if(data != null){
            String filepath ="D:\\" + filename;
            File file  = new File(filepath);
            FileOutputStream fos = new FileOutputStream(file);
            fos.write(data,0,data.length);
            fos.flush();
            fos.close();
        }
    }

字节流转文件，方法二：

        File file = new File("D:\\111.pdf");
        FileInputStream fis = new FileInputStream(file);
        byte[] bytes = IoUtil.readBytes(fis, true);
        FileOutputStream fos = new FileOutputStream("D://333.PDF");
        IoUtil.write(fos, true, bytes);