【转】Java中File,byte[],Object间的变换

【转】Java中File,byte[],Object间的转换

一、有两点需要注意：

????1、Object 对象必须是可序列化对象 。

??? 2、可序列化的 Object 对象都可以转换为一个磁盘文件；反过来则不一定成立，只有序列
???????? 化文件才可以转换为 Object 对象。

二、相关的转换方法：
??????

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?Byte_File_Object?...{

????/**?*//**
?????*?文件转化为字节数组
?????*?@Author?Sean.guo
?????*?@EditTime?2007-8-13?上午11:45:28
?????*/
????public?static?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];
????????????for (int n;(n = stream.read(b)) != -1;) {

out.write(b, 0, n);

}

????????????stream.close();
????????????out.close();
????????????return?out.toByteArray();
????????}?catch?(IOException?e)?...{
????????}
????????return?null;
????}

????/**?*//**
?????*?把字节数组保存为一个文件
?????*?@Author?Sean.guo
?????*?@EditTime?2007-8-13?上午11:45:56
?????*/
????public?static?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;
????}

????/**?*//**
?????*?从字节数组获取对象
?????*?@Author?Sean.guo
?????*?@EditTime?2007-8-13?上午11:46:34
?????*/
????public?static?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();
????}

????/**?*//**
?????*?从对象获取一个字节数组
?????*?@Author?Sean.guo
?????*?@EditTime?2007-8-13?上午11:46:56
?????*/
????public?static?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();
????}

}

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