Java File和byte数据之间的转换

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;
}

}