package cn.iworker.file;  

import java.io.BufferedOutputStream;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;  

public class FileTest

{  

    public static void main(String[] args)

    {

        file2BetyArray();

        fileToBetyArray();

        BetyToFile("D:\\Study\\Java\\First.class");

    }  

    public static byte[] file2BetyArray()

    {

        File file = new File("D:\\Study\\Java\\First.class");

        if (!file.exists()) {

            return null;

        }

        FileInputStream stream = null;

        ByteArrayOutputStream out = null;

        try {

            stream = new FileInputStream(file);

            out = new ByteArrayOutputStream(1000);

            byte[] b = new byte[1000];

            int n;

            while ((n = stream.read(b)) != -1) {

                out.write(b, 0, n);

            }

            return out.toByteArray();// 此方法大文件OutOfMemory

        } catch (Exception e) {

            System.out.println(e.toString());

        } finally {

            try {

                stream.close();

                out.close();

            } catch (IOException e) {

                e.printStackTrace();

            }  

        }

        return null;

    }  

    public static byte[] fileToBetyArray()

    {

        FileInputStream fileInputStream = null;

        File file = new File("D:\\Study\\Java\\First.class");

        byte[] bFile = null;

        try {

            bFile = new byte[(int) file.length()];

            fileInputStream = new FileInputStream(file);

            fileInputStream.read(bFile);

            fileInputStream.close();

            for (int i = 0; i < bFile.length; i++) {

                System.out.print((char) bFile[i]);

            }

            System.out.println("Done");

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            try {

                fileInputStream.close();

                bFile.clone();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

        return bFile;

    }  

    public  static File BetyToFile( String filePath)

    {

        File file = new File(filePath);

        BufferedOutputStream stream = null;

        FileOutputStream fstream = null;

        byte[] data=new byte[(int)file.length()];

        try {

            fstream = new FileOutputStream(file);

            stream = new BufferedOutputStream(fstream);

            stream.write(data);

        } catch (Exception e) {

            e.printStackTrace();

        } finally {

            try {

                if (stream != null) {

                    stream.close();

                }

                if (null != fstream) {

                    fstream.close();

                }

            } catch (IOException e1) {

                e1.printStackTrace();

            }

        }

        return file;

    }  

}  

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();

                }

            }

        }

    }