I have a system where a serialized file is created with a C# program and then deserialized in another C# program. I'm wondering if it's possible to do binary deserialization of a C# file in Java?
Thanks
You can try using some serializator that has implementations for both platforms and outputs data in a platform-independet format, like Protobuf.
Or if you need a full RPC over network between Java and C# application, you can go for Apache Thrift.
I assume you are speaking of an object serialized with BinaryFormatter. The answer then is a qualified "yes," since Java implements a Turing machine. However, this is will not be straightforward.
In this case the data will be in a format most suitable for consumption by a .NET runtime, and will contain information about .NET types and assemblies. You would have to implement your own reader for this format, and then have some way to map between .NET and Java types. (The Mono project implements a BinaryFormatter compatible with .NET's, so you could use their reader implementation as a reference.)
As an alternative, consider using another format for data serialization, such as JSON. This will give you instant portability to a wide array of languages, as well as the possibility for easy human inspection of the data.
Deserializing an object in Java which was serialized with C#'s built-in binary serialization would you'd to implement C#'s deserialization logic in java. That's a pretty involved process, so let's compare some options:
Use a third party library for serialization which works for C# and Java.
Write a routine to serialize each object. One in C#, one in Java. This will be tedious, and hard to maintain.
Implement C#'s serialization logic in Java, or vice versa. This will be difficult, time consuming, and you likely won't get it right the first time.
I recommend option 1, use a third-party library. Here's two third-party libraries I've used and highly suggest.
Google ProtoBufs
Apache Thrift
You can use any cross-platform binary format. Your options include, among others:
Protobuf
BSON (Binary JSON)
GZIP
JSON and XML (herrrrp) are also options, albeit text-based ones.
One other option would be to base64-encode the data, and decode it on the other side; albeit you may get a huge payload because it's binary (probably not a good idea).
Related
I am working on a project which is made up on c# and there are some of data are serialized And now I need the same values to be serialized in java.
So, can I get the java serialized out put which should equivalent to the c# serialized out put. Because c# code is already been done I cant change the reader format. I need to send the same data by java which is currently in c#.
So, is the serialized out put of both the language are same.
So, is the serialized out put of both the language are same.
Certainly not if you use the default binary serialization mechanisms of each platform. It would be almost inconceivable that they could be compatible.
You should pick a platform-neutral serialization format, such as Protocol Buffers, Thrift, YAML, JSON, XML (with custom serializers) etc.
The binary serialization is almost always not the same, because of different serialization implementations. However thats why we have XML or Json and other inter-compatible formats, so we can use them regardless of the technology we use.
Server side - C# or java
Client side Objective C
I need a way to serialize an object in C#\java and de-serialize it in Objective C.
I'm new to Objective C and I was wondering where I can get information about this issue.
Thanks.
Apart from the obvious JSON/XML solutions, protobuf may also be interesting. There are Java//c++/python backends for it and 3rd parties have created backends for C# and objective-c (never used that one though) as well.
The main advantages are it being much, much faster to parse[1], much smaller[2] since it's a binary format and the fact that versioning was an important factor from the beginning.
[1] google claims 20-100times compared to XML
[2] 3-10times according to the same source
Another technology similar to protobufs is Apache Thrift.
Apache Thrift is a software framework for scalable cross-language services development. Apache Thrift allows you to define data types and service interfaces in a simple definition file. Taking that file as input, the compiler generates code to be used to easily build RPC clients and servers that communicate seamlessly across programming languages.
JSON for relatively straight forward object graphs
XML/REST for more complex object graphs (distinction between Arrays / Collections / nested arrays etc)
Sudzc. I am using it. It is pretty easy to invoke a Webservice from i-os app.
You dont have to write code to serialize object.
JSON is probably the best choice, because:
It is simple to use
It is human-readable
It is data-based rather than being tied to any more complex object model
You will be able to find decent libraries for import/export in most languages.
Serialisation of more complex objects is IMHO not a good idea from the perspective of portability since often one language/platform has no effective way of expressing a concept from another language / platform. e.g. as soon as you start declaring "types" or "classes" of serialised objects you run into the thorny issue of differing object models between languages.
On iOS there are couple of JSON frameworks and libraries with an Objective-C API:
JSONKit
SBJson
TouchJson
are probably the most prominent.
JSONKit is fast and simple, but can only parse a contiguous portion of JSON text. This means, you need to save downloaded data into a temporary file, or you need to save all downloaded JSON text into a NSMutableData object (kept in memory). Only after the JSON text has been downloaded completely you can start parsing.
SBJson is more flexible to use. It provides an additional "SAX style" interface, can parse partial input and can parse more than one JSON document per "input" (for example several JSON documents per network connection). This is very handy when you want to connect to a "streaming API" (e.g. Twitter Streaming API), where many JSON documents can arrive per connection. The drawback is, it is a much slower than JSONKit.
TouchJson is even somewhat slower than SBJson.
My personal preference is some other, though. It is faster than JSONKit (20% faster on arm), has an additional SAX style API, can handle "streaming APIs", can simultaneously download and parse, can handle very large JSON strings without severely impacting memory foot-print, while it is especially easy to use with NSURLConnection. (Well, I'm probably biased since I'm the author).
You can take a look at JPJson (Apache License v2):
JPJson - it's still in beta, though.
I have a have a java project that serializes some objects and ints to a file with functions like
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeInt(RANK_SIZE);
oos.writeObject(_firstArray);
oos.writeObject(_level[3]);
oos.writeObject(_level[4]);
...
Now I have trouble deserializing that file with C# (tried the BinaryFormatter) as it apparently can only deserialize the whole file into a single object (or arrays, but I have different objects with different lenghts).
I tried first to port the generation of these files to C#, but failed miserably. These files are small and I don't must to generate them myself.
Do I need to alter the way those files are generated in Java or can I deserialize it in any way?
There is nothing in the standard .NET framework which knows how to deserialize Java objects. You could, in theory, use the Java serialization spec and write your own deserialization code in C#. But it would be a large and complex project, and I don't think you'd find many customers interested in using it.
Far, far easier would be to change the way you serialize the data to use a portable format: JSON, or some form of XML. There are both Java and C# libraries to deal with such formats and the total effort would be orders of magnitude less. I would vastly prefer this second approach.
Maybe an at first sight counterintuitive solution might be to serialize them to some commonly understandable format like JSON? I'm not even sure the binary format for serialized objects in Java is guaranteed to remain unchanged between Java versions....
Jackson is my personal favorite when it comes to Java JSON libraries.
http://www.ikvm.net/ IKVM can do it perfectly.
I have a .NET application which serializes an object in binary format.
this object is a struct consisting of a few fields.
I must deserialize and use this object in a C++ application.
I have no idea if there are any serialization libraries for C++, a google search hasn't turned up much.
What is the quickest way to accomplish this?
Thanks in advance.
Roey.
Update :
I have serialized using Protobuf-net , in my .NET application, with relative ease.
I also get the .proto file that protobuf-net generated, using GetProto() command.
In the .proto file, my GUID fields get a type of "bcl.guid", but C++ protoc.exe compiler does not know how to interpret them!
What do I do with this?
If you are using BinaryFormatter, then it will be virtually impossible. Don't go there...
Protocol buffers is designed to be portable, cross platform and version-tolerant (so it won't explode when you add new fields etc). Google provide the C++ version, and there are several C# versions freely available (including my own) - see here for the full list.
Small, fast, easy.
Note that the v1 of protobuf-net won't handle structs directly (you'll need a DTO class), but v2 (very soon) does have tested struct support.
Can you edit the .NET app? If so why not use XML Serialization to output the data in a easy to import format?
Both boost and Google have libraries for serialization. However, if your struct is pretty trivial, you might consider managing the serialization yourself by writing bytes out from C# and then reading the data in C++ with fread.
Agree with others. You are making your app very vulnerable by doing this. Consider the situation if one of the classes you're serializing is changed in any way or built on a later version of the C# compiler: Your serialized classes could potentially change causing them to be unreadable.
An XML based solution might work well. Have you considered SOAP? A little out of fashion now but worth a look. The main issue is to decouple the implementation from the data. You can do this in binary if speed / efficiency is an issue, although in my experience, it rarely is.
Serializing in a binary format and expecting an application in another language to read the binary is a very brittle solution (ie it will tend to break on the smallest change to anything).
It would be more stable to serialize the data in a common standard format.
Do you have the option of changing the format? If so, consider choosing a non-binary format for greater interoperability. There are plenty of libraries for reading and writing XML. Json is popular as well.
Binary formats are efficient, but vulnerable to implementation details (does your C++ compiler pack data structures? how are ints and floats represented? what byte ordering is used?), and difficult to adjust if mangled. Text based formats are verbose, but tend to be much more robust. If you are uncertain about binary representations, text representations tend to be easier to understand (apart from challenges such as code pages and wide/narrow characters...).
For C++ XML libraries, the most capable (and perhaps also most complex) would still seem to be the Xerces library. But you should decide for yourself which library best fits your needs and skills.
Use XML Serialization its the best way to go, in fact is the cleanest way to go.
XmlSerializer s = new XmlSerializer( typeof( YourClassType ) );
TextWriter w = new StreamWriter( #"c:\list.xml" );
s.Serialize( w, yourClassListCollection );
w.Close();
Is there an easy way to serialize data in c++ (either to xml or binary), and then deserialize the data in C#?
I'm working with some remote WINNT machines that won't run .Net. My server app is written entirely in C#, so I want an easy way to share simple data (key value pairs mostly, and maybe some representation of a SQL result set). I figure the best way is going to be to write the data to xml in some predefined format on the client, transfer the xml file to my server, and have a C# wrapper read the xml into a usable c# object.
The client and server are communicating over a tcp connection, and what I really want is to serialize the data in memory on the client, transfer the binary data over the socket to a c# memory stream that I can deserialize into a c# object (eliminating file creation, transfer, etc), but I don't think anything like that exists. Feel free to enlighten me.
Edit
I know I can create a struct in the c++ app and define it in c# and transfer data that way, but in my head, that feels like I'm limiting what can be sent. I'd have to set predefined sizes for objects, etc
Protocol Buffers might be useful to you.
Protocol buffers are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler. You define how you want your data to be structured once, then you can use special generated source code to easily write and read your structured data to and from a variety of data streams and using a variety of languages – Java, C++, or Python.
.NET ports are available from Marc Gravell and Jon Skeet.
I checked out all mentioned projects like prottocol buffers, json, xml, etc. but after I have found BSON I use this because of the following reasons:
Easy to use API
Available in many languages (C, C++, Haskell, Go, Erlang, Perl, PHP, Python, Ruby, C#, ...)
Binary therefore very space efficient and fast (less bytes->less time)
constistent over platforms (no problems with endianess, etc)
hierarchical. The data model is comparable to json (what the name suggests) so most data modelling tasks should be solvable.
No precompiler necessary
wideley used (Mongodb, many languages)
C++ doesn't have structural introspection (you can't find out the fields of a class at runtime), so there aren't general mechanisms to write a C++ object. You either have to adopt a convention and use code generation, or (more typically) write the serialisation yourself.
There are some libraries for standard formats such as ASN.1, HDF5, and so on which are implementation language neutral. There are proprietary libraries which serve the same purpose (eg protocol buffers).
If you're targeting a particular architecture and compiler, then you can also just dump the C++ object as raw bytes, and create a parser on the C# side.
Quite what is better depends how tightly coupled you want your endpoints to be, and whether the data is mainly numerical (HDF5), tree and sequence structures (ASN.1), or simple plain data objects (directly writing the values in memory)
Other options would be:
creating a binary file that contains the data in the way you need it
( not a easy & portable solution )
XML
YAML
plain text files
There are a lot of options you can choose from. Named pipes, shared
memory, DDE, remoting... Depends on your particular need.
Quick googling gave the following:
Named pipes
Named Shared Memory
DDE
As mentioned already, Protocol Buffers are a good option.
If that option doesn't suit your needs, then I would look at sending the XML over to the client (you would have to prefix the message with the length so you know how much to read) and then using an implementation of IXmlSerializer or use the DataContract/DataMember attributes in conjunction with the DataContractSerializer to get your representation in .NET.
I would recommend against using the marshaling attributes, as they aren't supported on things like List<T> and a number of other standard .NET classes which you would use normally.