my boss asked me to develop an webservice that should work in this matter:
an external app contact my app and:
if the method used is GET and the url contacted is:
http://localhost:8080/webapp/webservice/?findall
will return all rows find in a table;
If the same external app contact my app in the same method but send a key and a value like:
http://localhost:8080/webapp/webservice/?field1=value1
my app will return a set of rows filtered by field/value.
And soon on with with any method sending request and with other fields.
I know how do the operations using JPA 2.1 but how mapping the actions?
Someone could help me to starting in the right direction with JDK1.8?
Related
I am new in android and developing an android application in which admin can insert data on server and users can load that data on their devices. I don't want to load data from server every time user land on that activity. I want to save fetched data at client side using greendao and load only the new one. And i think i have to hit the backend at least once. I am looking for a most convenient method to achieve this.
My preferred way would be to track the device on the server side:
for example create a table like cachedDevices(deviceId,dataId). then whenever you are requesting new data, your server could query your data against cachedDevices internally and only send new data...
you should also be aware of that each device should have unique Id...
I know that returning a value from a JWSapp to the "calling" page cannot be done.
However, I use this JWSapp to get user ID from its biometric information.
The idea is that when you try to login, a button allows to launch the JWSapp that will deal with the biometric tasks and then return the user's idea.
Still, as I said, from a JWSapp I cannot send back the id to auto-complete the field. I found this post: Returning a value from a java web start application but I really need to keep the JWS (external constraints)...
So there's my question: is there any workaround to get the id back?
Thank you in advance :)
i was trying to call the following web service from my android app, it hung then completed without returning the result:
web service:http://androidexample.com/media/webservice/JsonReturn.php
However when I clicked on the link, it worked fine - the json file displayed. yet it would not work in my app..
but now, it works fine now in my android app, perhaps it was temporarily down is what I am guessing. How can I know if a web service is up and running for an android app to consume ?
Typically, web services are designed to have a status page that can return status text or a HTTP return code to indicate service status.
If it doesn't have that, you can design a function to periodically do a very basic request with a known result to determine state. This is much better than doing a simple ping.
If it was down it would most likely show a HTML error page, which your app would try to parse, which would cause an error.
I had a similar issue, because I needed to know if the user was returning HTML or the correct JSON, to do this I created the ArrayList I was about to use outside of the try/catch of the parse area. You should do the same if you are using a string.
What I mean is, use:
ArrayList<Something> arrayList = new ArrayList<Something>();
String testString = ""; instead of String testString = null;
I was using only ArrayList<Something> arrayList; at one point which is incorrect. If the user then returns HTML, you won't get an error, the user will simply return an empty arraylist or empty string.
You can then plan for that and show some sort of error message. This way you only need one network request but you can still plan for getting the data back, and the server being down.
I am working on a Phonegap application that uses an Android service to check for message updates while the app isn't being used. In order to do that, however, I need the session key generated by the user's username and password. The generation of the session key is handled on the Javascript/HTML side of things while the app is active in the foreground.
My question is, how do I access a Javascript variable for use in Java? I need the session key value as a String object in Java. I just need to access it once, and I don't have a clue how Javascript-to-Java communication works.
You can pass a javascript variable to the java while using the plugins as below.
cordova.exec(null, null, "service", "action", ["firstArgument", "secondArgument", 42]);
Here the first and second parameter to the exec method are the sucess and failure calllback.
service and action are the native class and method names respectively.
And the last parameter ["firstArgument", "secondArgument", 42] are the javascript variables which you can pass to the native method.
For more details please go through the following link.
http://docs.phonegap.com/en/2.8.0/guide_plugin-development_index.md.html
my question is how to push data from server in atmosphere without using javaScript
I followed the chat tutorial it was so understandable, now I want to push data from an action in struts 2 (and not from javascript) i know that I must call .onMessage() method but I'm blocked on how to build AtmosphereResponse argument I tried
AtmosphereResponse response = new AtmosphereResponse.Builder().build();
but it return NullPointerExeption when I use response.write() methode
thanks a lot for your collaboration
Solution : BroadcasterFactory.getDefault().lookup("/atmosphere").broadcast(message);
"/atmosphere" is your AtmosphereServlet pattern