为什么我应该在Java中使用序列化而不是文件I / O

Question

在序列化机制中，我们使用objectinputstream和object outputstream将对象写入流中。这些对象通过网络传递。在这种机制中，使用Object输入/输出流。那么我可以使用File INPUT / OUTPUT Streams代替调用序列化标记接口吗？ 。

Answer 1

I guess You are mixing up serialization and general I/O.

Serialization is a way to transform objects into byte sequences (and back, which is called Deserialization). This way, You can transmit serializable objects over the network and store them into files.

File input/output streams are for storing/reading any kind of data to/from files.

Answer 2

First let's concentrate on the definition: Serialization: It is the process of converting object state into a format that can be stored and reconstructed later in the same way.

Whereas in file I/O it can't be possible to store data-structure or object and reconstructed later in the same way. That's why we use serialization or database query methods (like sql, mongodb).

JSON/XML can also be used for serialization using its parser.

Take an example of javascript (not java, but take it like language-agnostics):

var obj = { // it's an object in javascript (same like json) a: "something", b: 3, c: "another" };

Now if you try to use file i/o in this to save in a file (say abc.txt), it will be saved as a string which means it can't be accessed later in other code by reading this file (abc.txt) like this:

// readThisFile();

// obj.a;

But if you use serialization (in javascript using JSON natively), you can read it from the file

Answer 3

when you need to transfer your object on network, you need to serialized it. Below link might be useful for you.

http://java.sun.com/developer/technicalArticles/Programming/serialization/

Answer 4

File I/O and Serialization are two different things. File I/O is used to read/write a file. Serialization interface is used for binary interpretation of an object. So NO, you can't use File Streams for sending over network.(maybe there is some workaround for sending data over network using file streams, but its like trying to fly with a car)

Answer 5

Since streams are additive, you can do something like

FileOutputStream fos = new FileOutputStream("/some/file/to/write/to");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(someObject);

Not sure this is what you were asking, but it's hard to tell.

Answer 6

Serialization/Deserialization is used to read and write objects, which not only makes compressed data, which is unreadable but also is writes it in binary. The File I/O is used for reading and writing. It appears that you do not want to serialize, if you don't, well do not use it. Read and write your files in text.

Answer 7

In serialization mechanism,we write the object into s stream using ObjectInputStream and ObjectOutputStream .

Ok

These objects are passed across the network.In this mechanism using a ObjectInput/Output stream.

I am following you.

So can I use File Input/Output streams instead of calling serialization marker interface?.

Here you lost me. Do you mean to send an object over the network or just to serialize it?

Of course you can use whichever Input/Output streams along with ObjectInput/ObjectOutput streams to serialize objects to different media.

For instance:

ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("jedis.bin"));
out.writeObject(new Jedi("Luke"));

Would serialize the object into a file called jedis.bin

And the code

ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
ObjectOputStream out = new ObjectOutputStream(byteStream);
out.writeObject(new Jedi("Luke"));

Would serialize the object into a memory array.

So, anything that is an output/input stream is subject of being used as the underlying stream used by ObjectInput/ObjectOutput streams.