How to connect to Oracle with a Java program?
you need to go through JDBC tutorial.
You should never really have anything other than presentation logic in JSP. I am worried that thinking of connecting to Database from JSP is a bad idea. Use Servlets with JSP. Keep JDBC connectivity in servlet and presentation logic in JSP.
As long as solving your problem stands, you can just embed Java code in JSP as mentioned here Establishing a Connection. For Oracle, use URL like
jdbc:oracle:thin://[host][:port]/SID
See this worked example.
I should point out that doing database transaction inside a JSP is not a good idea. It is generally thought to be better to do the request argument processing and database heavy lifting in a pure Java servlet within your webapp, attach the results as request attributes, and then use the request dispatcher to 'forward' to or 'include' the JSP.
One problem with doing database stuff in the JSP itself is that it is difficult to report problems properly. For instance the JSP will most likely commit the response right at the beginning, making it impossible to change the response status code and/or headers. The net result could be the delivery of a truncated page with the wrong status code.
You can try this:
connect = DriverManager.getConnection("jdbc:oracle:thin:xyz/ abc#(descrip
tion=(address_list=(address=(protocol=tcp) (host=servername or ip)
(port=1521))) (source_route=yes)(connect_data=(sid=ora)))");
Related
I'm developing a web app using JSTL and Javascript in Eclipse Juno. I've been reading questions like How to set the JSTL variable value in javascript? and my code works good even if I have error in eclipse:
But... Is it a good practice to use JSTL and Javascript like this?
Does it cause a low performance in the time of rendering the webpage?
Can this be done in other way?
Is it a good practice to use JSTL and Javascript like this?
It is not bad practice or good practice. The bad practice would be using JSTL to control the flow of JavaScript, which is plain wrong because JSTL runs on server side and JavaScript on client side.
Does it cause a low performance in the time of rendering the webpage?
JSTL will only help to generate the HTML for the current view. JavaScript is not involved in the HTML generation at server side but at client side unless you work with nodejs or similar technologies.
Can this be done in other way?
This depends on what you're doing. Common way to access to data when accessing to a web page:
Application Server (AS) receives a GET request on http://www.foo.com/bar
AS pre process the GET request (load data from database or another data source, pre calculations, etc)
AS creates the response for the GET request (apply the data to generate the HTML)
AS sends the response to the client.
The browser client renders the HTML.
Another way to do it:
Application Server (AS) receives a GET request on http://www.foo.com/bar
AS creates the response for the GET request (generate the HTML which contains JavaScript functions to load the data in the onload event).
AS sends the response to the client.
The browser client renders the HTML.
The onload event fires and load data in the onload event through RESTful services. This way, the data interaction is handled in client side only, but the data comes from server side.
These are two very simple alternatives to handle the same problem. Which one to choose and work with will depend entirely on your design, there's no definitive answer.
yesterday i started brainstorm for a project of mine and I'm not sure if its the correct approach.
On my website I'm having an (kind of an order form) which sends a post to a target URL, which works with a simple curl php script. The target is an external service (where I have no access no rights, nothing). I only know that I will get a POST with further processed data back from the service, which I have to save into my DB.
in steps:
Users fills out the (order) form and posts data to an external url on my website.
data gets externally handled and after finishing that resents a post.
read incoming post data.
save data into DB.
Success page on my website.
My thoughts were to handle the incoming data with a servlet (spring maven project) but I'm not sure if this is a correct approach. Is there a better why to do this. Or is the first step with the php scripts wrong. thx for any help.
A simplest workflow could be
1. Forward the initial (Order form with values) request to a servlet
2. Invoke a post request using java to an external url inside this servlet (Using Apache http client, or libraries such as HTMLUnit)
3. Once you get the incoming response in your servlet, you can update your database.
If you are using spring, the controller could forward initial request to a business class which will handle this post processing and delegate the database update to respective DAO.
There are a number of suitable ways to handle this, and the decision is largely a matter of preference and what you're familiar with. Spring can handle this sort of job quite well.
Note: Maven is a build system for Java and some other JVM languages. I recommend using it, but it's not part of Spring; what you're probably looking for is Spring MVC.
I created a java swing applet and inserted it in to a web page but I can't connect to the database through the web page how can I solve it? Please help.
You're facing several things here:
your applet by design can't connect to any resources except those hosted on the same host as the applet itself
your applet when run directly from a webbrowser (so not called from an http server but loading the html page it sits in from your harddisk) has no host so can't connect to anything at all
as mentioned in comments, having an applet contain account information for a database (or indeed anything) is a massive security risk
not even mentioning scalability concerns here, at your level of competence you'll not run into problems with that as not enough people will ever access your applet (no insult intended, but if you don't know this you're not going to be working for a high traffic website as they'd never have hired you)
Best thing to do is have the applet call a servlet using HTTP calls, then have the servlet do the database work and return the results to the applet, NOT the ResultSet or other JDBC entities, but turn the result into something like an XML document or CSV and send that back in the HTTP response.
The database code is below:
Class.forName("Driver Name");//example Driver Name="sun.jdbc.odbc.JdbcOdbcBridge" if your are using ODBC Driver
Connection con=DriverManager.getConnection("Connection String");
This question is about a proper architecture using JSP as a controller for ExtJS.
I am fairly new to server side development but I am pretty familiar with ExtJS 4 and getting better with Java and SQL daily.
I am trying to create a JSP controller to write the data from stores in ExtJS. I have MSSQL database and Tomcat running on the server.
I successfully created a JSP (sqlData.jsp) that reads from the database and returns JSON data. I pass a query name to this JSP, it then looks up what the query is from a "query" table (columns: [query_id],[query_name],[query]). It then runs the query and returns the data in a JSON format - this is working fine to get data into ExtJS from a database.
To use this backend set-up I usually configure the store like this:
var store = Ext.create('Ext.data.Store', {
model: 'aModel',
proxy: {
type: 'ajax',
url: 'sqlData.jsp?queryName=aQueryName',
reader: 'json'
},
autoLoad: true
});
Somehow, I need this sqlData.jsp to also handle a store.save() call from the ExtJS framework. Which means the JSP needs to receive a POST request and then do an update based on a pile of JSON data (ExtJS sends read request as GET and write methods like store.save() are POST).
My plan was to add something in the Java to recognize whether it is a POST or GET request. Then, if it is a POST request, I would send it to a different Java method in the JSP to parse the JSON and write it to the database.
Of course I would have to change my "query" table to have another column for update/insert statements linked to the same queryName (i.e.: [query_id],[query_name],[select_query],[update_query]).
Does this backend implementation make any sense?
Anyone else use JSP and ExtJS to achieve this smoother?
I noticed that there is an api config option I can set in my proxy to specify different URLs for the different operations (READ, WRITE, DELETE, etc). Should I make a separate JSP and direct all write requests using this config instead?
Would it be wiser to add a writer: 'json' config on the proxy so that it parses before POSTING? I figured I would have to parse it in the JSP either way so I didn't think I should.
Any pointers will be much appreciated.
since your backend is Java, I would really recommend using Spring 3.0 MVC to code your backend.
JSP is not a good option for the stuff you are doing because:
the functions you write in there are not unit testable.
the functions you write in there are not reusable.
the code you write in JSP are functional in nature, not object oriented, you can't inject the services you need into your JSP.
Spring 3.0 MVC has really good synergy with ExtJS 4, namely the RESTful URL's and content negotiation.
This example shows how to integrate the two things together. http://java.dzone.com/articles/extjs-4-file-upload-spring-mvc
I would skip jsp and just go directly to servlets. i.e. implement the logic in the servlets for both returning json, and handling things like POST, PUT, etc.....
jsps are meant to be views. But in your case, your view layer is its own application running in the client. You only need the data.
The Servlet API puts allows you to handle requests, get the http method, and stream data to the response.
My advice is go with an MVC server side framework. My favorite is Grails which lets you work with JSON objects directly for both input and output. Its also super simple to with grails to read and write data to the database.
I a deveveloping a web site that comunicates with a custom made webserver by me in Java. The web site is made in PHP/JavaScript/JQuery running on Apache and i made a simple second webserver in Java to support some designed features by me, and this server runs under another port XXXXX. The problem is, i want to make requests in jQuery to second server the domain is diferent, the page runs on domain and the $.getJSON function calls domain:XXXXX wich is not allowed. I thought user $.getJSONP but im concerning concerned issues. The connections between two points is authed (i was think by passing a token beyond the callback generated by jquery). The two poins are supported by. Is there safe in this case use $.getJSONP or exists other alternatives thinking in browsers support(IE7+ and FF3+).
Sorry for my english :)
Best regards lealoureiro
JSONP should work for your needs, however your other option would be to have a proxy service on your second server that would make the request server side. Your client-side code could then access all the data natively via json instead of jsonp.