java文件的读写

public File getFileFromBytes(byte[] b, String outputFile){
		BufferedOutputStream stream = null; 
        File file = null; 
        try{ 
            file = new File(outputFile); 
            FileOutputStream fstream = new FileOutputStream(file); 
            stream = new BufferedOutputStream(fstream); 
            stream.write(b); 
        } catch (Exception e){ 
            e.printStackTrace(); 
        } finally{ 
            if (stream != null){ 
                try{ 
                    stream.close(); 
                } catch (IOException e1){ 
                    e1.printStackTrace(); 
                } 
            } 
        } 
        return file; 

	}

 

public static ByteArrayOutputStream readFile(String filename) {
    try {
        FileInputStream fileInStream = new FileInputStream(filename);
        ByteArrayOutputStream fileByteStream = new ByteArrayOutputStream();
        int i = 0;
        while ((i = fileInStream.read()) != -1) {
            fileByteStream.write(i);
        }
        fileInStream.close();
        return fileByteStream;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

public static void writeFile(String fileName, byte[] data) {
    try {
        FileOutputStream fos = new FileOutputStream(fileName);
        fos.write(data);
        fos.close();
    } catch (Exception e) {
        e.printStackTrace();
    }

}
//transfor InputStream to byte
public static byte[] getBytes(InputStream is) throws Exception {
    byte[] data = null;

    Collection chunks = new ArrayList();
    byte[] buffer = new byte[1024 * 1000];
    int read = -1;
    int size = 0;

    while ((read = is.read(buffer)) != -1) {
        if (read > 0) {
            byte[] chunk = new byte[read];
            System.arraycopy(buffer, 0, chunk, 0, read);
            chunks.add(chunk);
            size += chunk.length;
        }
    }

    if (size > 0) {
        ByteArrayOutputStream bos = null;
        try {
            bos = new ByteArrayOutputStream(size);
            for (Iterator itr = chunks.iterator(); itr.hasNext();) {
                byte[] chunk = (byte[]) itr.next();
                bos.write(chunk);
            }
            data = bos.toByteArray();
        } finally {
            if (bos != null) {
                bos.close();
            }
        }
    }
    return data;
}