File,Byte[],Object相互转化.

import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class FileUtil {

/**
* .
* TODO 把字节数组保存为一个文件
* @param f
* @return
*/
public byte[] getBytesFromFile(File f) {
if (f == null) {
return null;
}
try {
FileInputStream stream = new FileInputStream(f);
ByteArrayOutputStream out = new ByteArrayOutputStream(1000);
byte[] b = new byte[1000];
int n;
while ((n = stream.read(b)) != -1)
out.write(b, 0, n);
stream.close();
out.close();
return out.toByteArray();
} catch (IOException e) {
}
return null;
}

/**
* .
* TODO 把字节数组保存为一个文件
* @param b
* @param outputFile
* @return
*/
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;
}

/**
* .
* TODO 从字节数组获取对象
* @param objBytes
* @return
*/
public Object getObjectFromBytes(byte[] objBytes) throws Exception {
if (objBytes == null || objBytes.length == 0) {
return null;
}
ByteArrayInputStream bi = new ByteArrayInputStream(objBytes);
ObjectInputStream oi = new ObjectInputStream(bi);
return oi.readObject();
}

/**
* .
* TODO 从对象获取一个字节数组
* @param obj
* @return
*/
public byte[] getBytesFromObject(Serializable obj) throws Exception {
if (obj == null) {
return null;
}
ByteArrayOutputStream bo = new ByteArrayOutputStream();
ObjectOutputStream oo = new ObjectOutputStream(bo);
oo.writeObject(obj);
return bo.toByteArray();
}

}