Java文件File转byte[]

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最新推荐文章于 2025-01-21 00:16:41 发布

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分类专栏： Java学习文章标签： java

本文链接：https://blog.youkuaiyun.com/yangdonghhm/article/details/84537320

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本文介绍了一种使用Java实现文件读取与写入的方法。通过将文件转换为字节数组进行处理，实现了文件的复制功能。代码示例中包含了异常处理机制，确保了文件操作的安全性。

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// 转：http://forai.iteye.com/blog/1221081
public class T3 {

	public static void main(String[] args){
		String filePath = "E:\\softoon\\workspace_softoon\\TestMobile\\src\\1.docx";
		String outFilePath = "E:\\softoon\\workspace_softoon\\TestMobile\\src";
		String outFileName = "2.docx";
		
		getFile(getBytes(filePath),outFilePath,outFileName);
	}

	/**
	 * 获得指定文件的byte数组
	 */
	public static byte[] getBytes(String filePath){
		byte[] buffer = null;
		try {
			File file = new File(filePath);
			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();
			bos.close();
			buffer = bos.toByteArray();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return buffer;
	}

	/**
	 * 根据byte数组，生成文件
	 */
	public static void getFile(byte[] bfile, String filePath,String fileName) {
		BufferedOutputStream bos = null;
		FileOutputStream fos = null;
		File file = null;
		try {
			File dir = new File(filePath);
			if(!dir.exists()&&dir.isDirectory()){//判断文件目录是否存在
				dir.mkdirs();
			}
			file = new File(filePath+"\\"+fileName);
			fos = new FileOutputStream(file);
			bos = new BufferedOutputStream(fos);
			bos.write(bfile);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (bos != null) {
				try {
					bos.close();
				} catch (IOException e1) {
					e1.printStackTrace();
				}
			}
			if (fos != null) {
				try {
					fos.close();
				} catch (IOException e1) {
					e1.printStackTrace();
				}
			}
		}
	}
}

public static byte[] File2byte(String filePath)
	{
		byte[] buffer = null;
		try
		{
			File file = new File(filePath);
			FileInputStream fis = new FileInputStream(file);
			ByteArrayOutputStream bos = new ByteArrayOutputStream();
			byte[] b = new byte[1024];
			int n;
			while ((n = fis.read(b)) != -1)
			{
				bos.write(b, 0, n);
			}
			fis.close();
			bos.close();
			buffer = bos.toByteArray();
		}
		catch (FileNotFoundException e)
		{
			e.printStackTrace();
		}
		catch (IOException e)
		{
			e.printStackTrace();
		}
		return buffer;
	}

	public static void byte2File(byte[] buf, String filePath, String fileName)
	{
		BufferedOutputStream bos = null;
		FileOutputStream fos = null;
		File file = null;
		try
		{
			File dir = new File(filePath);
			if (!dir.exists() && dir.isDirectory())
			{
				dir.mkdirs();
			}
			file = new File(filePath + File.separator + fileName);
			fos = new FileOutputStream(file);
			bos = new BufferedOutputStream(fos);
			bos.write(buf);
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
		finally
		{
			if (bos != null)
			{
				try
				{
					bos.close();
				}
				catch (IOException e)
				{
					e.printStackTrace();
				}
			}
			if (fos != null)
			{
				try
				{
					fos.close();
				}
				catch (IOException e)
				{
					e.printStackTrace();
				}
			}
		}
	}
//转：http://blog.youkuaiyun.com/commonslok/article/details/9493531

以下是fileUpload.jar写法

DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setHeaderEncoding("utf-8");
String enCoding = request.getCharacterEncoding();
if(enCoding != null){
 upload.setHeaderEncoding(enCoding);
			}

			
			List fileItems = upload.parseRequest(request);
			Iterator iter = fileItems.iterator();