mySQL connection with javascript

Question

Good day! Here's the situation. We are trying to connect our mySQL database using javascript. We already have the java codes to access the database, but the thing is, they are java files and I cannot find ways how to transform them to javascripts. How can these different classes (e.g. DatabaseClass.java, DBConnectionFactory.java, DBConnectionFactoryImpl.java) work together in an HTML file? Can someone provide a link which could help us with this?

P.S. We're just beginners. I hope you guys can understand what we are trying to do. Cheers!

• Buggabill: See the answer to this question.
• Jite: If you are thinking of doing front-end database connections i would STRONGLY suggest another approach. That is a very big vulnerability, due to the fact that any client have full control of the client-side code.
• user2836881: I have read some of the disadvantages of using javascript to connect to the database. However, we are required to use javascript on this project.
• Jite: You should ask for clarification on the project rules in that case. Maybe you are intended to use server-side js, Node.js or something? I cant believe that any teacher or senior (not sure if school or work) would suggest to do client-side database connections.
• Jite: Reading the other comments and posts, I would believe that your professor have created a API that you are supposed to use via javascript. Could this be the case? Then its probably AJAX you are after.

Answer 1

You're mistaking that Java and Javascript are somehow related. They're not, and you can't just magically use Java classes in Javascript.

You need to have Java access the database, and communicate with the Java backend from Javascript.

• user2836881: So the codes that we have done using an IDE is totally different from what we will be using to write an HTML file?
• Kayaman: That's a broad question, which is also technology dependent, but basically yes. Which technologies are you using? Servlets on Tomcat? JSP? Pure Javascript?
• user2836881: I believe that is only pure javascript that we're dealing with. Our problem is that our professor left us with working java DB connector files, and he expects us to be able to access the database with our HTML projects using javascript.
• Kayaman: He can't be expecting that, since it's not possible (except in a very limited sense). You'll need to clarify the requirements from your teacher.

Answer 2

You need to make a server call to get data from the database. It is bad practice to call the database directly from the client side (you don't want to expose a database login to the client).

If you know what to look for when the page is called you can make the page a servlet, JSP, CGI-script or any other technology that facilitates dynamic web pages.

If you know (or want to learn) java I would recommend a servlet (with java code) that forwards to a jsp (for the presentation). Note that you need an application server that supports servlets and jsp.

If you need to make the database call on the fly, after the page has loaded, you can use Ajax or AJAJ to call a servlet (or other server side facility).

• Gimby: Exactly that. (client side) Javascript code is as visible as you can make it and if it wants to connect to a database, you need to store the connection details SOMEWHERE, which is going to be where the javascript code can reach it, and thus the browser can reach it because it is the browser that will be executing said Javascript, and thus anyone using the browser can also reach it since whatever is visible to the browser is visible to its user no matter how much trickery you throw at it to hide implementation details. Its just a Really Bad Idea (TM).

Answer 3

my two cents: if you need to work with Java and a DB, don't go for HTML. HTML is static, while it seems you want a dynamic application. then the best option (for beginners) would be to learn basic JSP and Servlets.

it is possible to access a database using JavaScript (though I wouldn't recommend it), here and here you can find topics on that subject.

• Kayaman: I'll eat my shorts if the professor wants them to use an IE specific Windows solution. But seems you got the "correct answer".
• user2836881: Those snippets gave me an idea. Thanks! One more thing, how about those java imports which have to be declared so classes would work properly? Aren't they important when it comes to javascript?
• Klas Lindbäck: You aren't actually considering calling the database directly from javascript? Seriously? DON'T! It is wrong in so many ways.
• Klas Lindbäck: Just don't submit it as a work sample when you are looking for a job.
• Jite: Does it run? Cause I cant believe that any teacher would supply you with server-side java code to look at and convert to client-side javascript, including DB connections and all. That would be like giving you a recipe on stew as an example on how to cut down a tree.

Answer 4

I think you'd better learn basic JSP/servlet , and then you can use then through a web server like tomcat ...