I'm building a small webservice and the client is an android client.
I must use dates and I want to save it in my database.
The server side is in PHP and the client is in Java. What format is the best to send date to PHP and how can I convert it easily ?
EDIT: When i say format, i'm not talking of the data format. Just the format of the date. Because the data are sent with JSON but the dates are passed as string.
I was thinking about the timestamp but it's not a good idea since we know its size limit...
Thanks.
#Gp2mv3 -
jmort253 is correct: JSON is an excellent data interchange format. Go for it!
You can use getTimeStamp()" on the PHP side
You can convert a PHP timestamp to a Java long timestamp as follows:
Date d=new Date((long)phpTimeStamp*1000);
PS:
If you use timestamps, you must never assume the client and the server are in any way synchronized with each other.
The main advantage of RESTful webservices is that you can easily send data from one application to another, using a common transport that both will understand.
Both XML and JSON have been used to facilitate communication between different applications, even if they're both written in different languages.
While XML is a great solution, JSON has been gaining traction as a strong option due to it's simplicity and out-of-the-box compatibility with JavaScript.
In Java, you could use a library called Jackson, which will serialize your classes into JSON and deserialize JSON strings back into Java classes.
Also, I'm not sure what you have against timestamps. Since they are long values, they should be really easy to work with in terms of date comparisons, and they should be easy to store since they're typically long values.
the easiest and most common way to store is using timestamps.
you can anytime change this timestamp into the required format using DateFormat. i hope that helps.
Related
I'm communication with a web service and it the json response has dates in it. the problem is those dates are in different formats. is there a generic way to parse these strings?
You should probably have an ordered list of formats to try (ideally using Joda Time as a far better API than the built-in one) and try each in turn until one works. It's not ideal in terms of performance (all the exceptions for failure) but it'll work and should be reasonably clear.
Of course, if you can get in touch with the web service provider and suggest that they return a standard format instead, that would be cleaner...
I'm new to Java. I want to send an array (ArrayList) of objects over the network via Java Web Service to my Silverlight app. This ArrayList contains custom class objects:
ArrayList<SVNSearchResult> results
so I'm thinking the best way is to serialize this to an XML String and on the Silverlight part, use LinQ to parse it. If there's a better way to send it please let me know. Thanks.
XML is a good fit for this. JSON would be one of the other usual suspects these days.
Whatever format you end up choosing, make sure you get the encoding right.
For a starter, try JSON. It has a network-efficient format, and is supported by any major language in the world.
XML is only my second choice as it is more complicated to generate/parse and is more verbose.
Is there any way to deserialize in PHP an object serialized in Java? IE If I have a Java class that implements Serialization and I use an ObjectOutputStream to write the object, and convert the result to a string, is there a way in PHP to take that string and create a similar object representation from it?
What does the Java Serialized data look like?
Response:
���sr�com.site.entity.SessionV3Data���������xpsr�java.util.HashMap���`��F�
loadFactorI� thresholdxp?#�����w������t� sessionIdt�0NmViMzUxYWItZDRmZC00MWY4LWFlMmUtZjg2YmZjZGUxNjg5xx
:)
I would heavily recommend you don't do this. Java serialization is meant for a Java instance to both save and load the data (for either transmission to another Java application or persistence between invocations of the same application). It was not at all meant to be a cross-platform protocol.
I would advise you to make an API adapter layer between the two. Output the contents of your Java object to a format you can work with in PHP, be it XML, YAML, or even a binary format (where you could use DataOutputStream).
What is the easiest way to eat soup with chopsticks when the soup was put in a bowl with a ladle? Put the soup in a cup and discard your chopsticks, because chopsticks are a poor choice for aiding in the consumption of soup. A cup (ubiquitous) eliminates external dependencies except for "mouth" and "opposable thumbs", both of which come with the standard library of humans.
A more elegant solution would be to encode that Java object with a JSON Serializer or XML serializer. Protocol Buffers or any other intentionally cross-language serialization technique would work fine plus Protocol Buffers can efficiently encode binary data.
Some time ago i did something simillar. However i didn't make PHP read "Java serialize" format. I did the oposite, that is, made Java serialize itself to a "PHP serialize" format. This is actually quite easy. Have look at PHPSerializedResponseWriter class that is a part of Solr package:
https://github.com/terrancesnyder/solr-analytics/blob/master/solr/core/src/java/org/apache/solr/response/PHPSerializedResponseWriter.java
...then all you have to do is just read the string and call:
$result = unserialize($string);
From comments in the online PHP manual, there is a Java class that serializes to the PHP serialization format that you can look into. Then you can unserialize the data using the standard PHP functionality.
Is it possible to use one of the more common cross platform data formats like JSON to communicate between your Java app and PHP? PHP has plenty of parsers for those formats. Check out json_decode for an example.
Is there any way to deserialize in PHP
an object serialized in Java?
Yes. The question is, should you? Exporting the Java object as XML or JSON probably makes more sense.
The following SO question might also help.
Dynamically create PHP object based on string
I'm trying to read a file that was created in a Java-based game using ObjectOutputStream in PHP. The data is a serialized object written in a binary format.
I've been using fopen and fread to get the binary data, but I have absolutely no idea what to do with it.
PHP doesn't understand Java. Both do however understand a common format like JSON, XML, CSV, etc. I'd suggest to change the format to either of them and use that as data transfer format instead.
In case of JSON, you can in Java use Google Gson to convert (encode) fullworthy javabeans into JSON flavor and in PHP you can use json_decode() to convert (decode) it into an associative PHP array.
It doesn't seem easy to reimplement http://download.oracle.com/javase/6/docs/platform/serialization/spec/protocol.html
You can't do it so easily (unless an existing framework is available). This because the binary format used by Java serialization is highly specialized to the JVM, think that there's not guaranteed compatibility even between different JVM versions.
You should use a different approach, for example using XML, YAML or JSON..
JSON stands for JavaScript Object Notation. But how come languages like php, java, c etc can also communication each other with json.
What I want to know is that, am i correct to say that json is not limited to js only, but served as a protocol for applications to communicate with each other over the network, which is the same purpose as XML?
JSON cannot handle complex data hierarchies like XML can (attributes, namespaces, etc.), but on the other hand you don't get the same overhead with JSON as you get with XML (if you don't need the complex data structures).
Since JSON is plain text with a special notation for JS to interpret, it's an easy protocol to adopt in other languages.
It is easy for a JS script to parse JSON, since it can be done using 'eval' in which the JS enginge can use its full power.
On the other hand, it is more complicated to generate JSON from within JS. Usually one uses the JSON package from www.json.org in which an object can easily be serialised using JSON.stringify, but it is implemented in JS so its not running with optimal performance.
So serialising JSON is about the same complexity using JS as when using Java, PHP or any other server side language.
Therefore, in my opinion, JSON is best suited when there is asymmetry between produce/consumer e.g. a web server that generates a lot of data that is consumed by the web application. Not the other way around.
But! When one choses JSON as data format it should be used in both directions, not XML<>JSON. Except for when simple get requests are used to retrieve JSON data.
yes, JSON is also wildly used as a data exchange protocol much like XML.
Typically a program (not written in JavaScript) needs a JSON library to parse and create JSON objects (although you can probably create them even without one).
Your right - it's a light weight data interchange format -- more details at: http://www.json.org
You are completely correct. JSON definition of how data should be formatted. It is more light weight than XML and therefore well suited to things like AJAX where you want to send data back and forth to the server quickly.