java二进制文件与字节之间的转化

1、将二进制文件变成字节

public static byte[] getFile(String path) throws Exception {
		byte[] b = null;
		File file = new File(path);

		FileInputStream fis = null;
		ByteArrayOutputStream ops = null;
		try {

			if (!file.exists()) {
				System.out.println("文件不存在！");
			}
			if (file.isDirectory()) {
				System.out.println("不能上传目录！");
			}

			byte[] temp = new byte[2048];

			fis = new FileInputStream(file);
			ops = new ByteArrayOutputStream(2048);

			int n;
			while ((n = fis.read(temp)) != -1) {
				ops.write(temp, 0, n);
			}
			b = ops.toByteArray();
		} catch (Exception e) {
			throw new Exception();
		} finally {
			if (ops != null) {
				ops.close();
			}
			if (fis != null) {
				fis.close();
			}
		}
		return b;
	}

 2、将字节保存成文件，如果文件存在，会被覆盖，要自己判断

public static void saveFile(byte[] b, String path)
			throws Exception {
		File file = new File(path);
		FileOutputStream fis = null;
		BufferedOutputStream bos = null;
		try {
				fis = new FileOutputStream(file);
				bos = new BufferedOutputStream(fis);
				bos.write(b);
		} catch (Exception e) {
			throw new Exception(e);
		} finally {
			if (bos != null) {
				bos.close();
			}
			if (fis != null) {
				fis.close();
			}
		}
	}

 3、直接打开文件：先调用saveFile, 将文件保存到一个临时目录，调用了cmd命令打开文件，windows操作系统自动调用应用程序打开，非Windows系统上无效。

Runtime runtime = Runtime.getRuntime();
runtime.exec("cmd /c start " + path);

评论

2 楼 luchenqun 2014-05-08  

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

1 楼 luchenqun 2014-05-08