Read/write json from js to file on server (not server app)

I'm working with a .js client and have and object that开发者_如何学Python I need to write out to a file on the server. A couple of questions - file i/o with JavaScript is new to me... I was planning on using jquery and json. I'm using java serverside. I don't have a problem reading what I get back from my servlet, but the file i/o is killing me! A couple of questions:

1. I can open a file I generated myself via the .js with an $.ajax call, but it's not handling my json syntax (I tried both an $.getJson and $.ajax - handwritten json, so I might (probably) are doing something wrong with it). I used firebug's console and it looks ok...

2. How can I write my object to a file on the server?

3. Then, when I want to read it, what do I need to do to process it? Right now I'm using a jsonFilter function (uses JSON.parse if that's available, otherwise eval) to process data that I'm getting from the servlet.

4. The object I'm writing isn't simple, but it's not super complex either. There's an array that contains an array, but that shouldn't make a difference if the software is both reading/writing it.

Thanks for any help! I'm at a loss - tried alot of different things.

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1. You can open a file located on the server via ajax by querying the file and loading it into a JSON object. You might want to LINT your JSON

2. You can not write to an object on the server via the client. This is a severe security breach. Common practice is to change the JSON data and then send it via ajax to server-side code. The server will then do the file IO.

3. Yes using JSON.parse otherwise eval is indeed correct. I would recommend json2.js

4. The data should be fine as long as it passes JSONLint.

Your main issue is that it's impossible to write to the server from the client. Get the client to load the data through ajax change it and then query the server to update the file.

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js don't have i/o property;

you should use ajax or http request to send message to server,and tell server to do de i/o action...