I have a table with 2 columns for storing application settings in Oracle database.
This is a just basic example: I want to create a java method which updates the values with prepared statement.
List; /** * Abstract * This DAO class provides CRUD database operations for the table book * in the database.
If available (not null) the form is in editing mode, otherwise it is in creating mode. This method is invoked only one time during life cycle of the servlet so it’s reasonable to put the DAO instantiation code here: It looks something like this when an error occurs: So far we have completed the code of the project.
Next, we need to implement a Data Access Layer (DAO) class that provides CRUD (Create, Read, Update, Delete) operations for the table book in database. In addition, for each individual book there are two links for editing (Edit) and deleting (Delete). * @author public class Controller Servlet extends Http Servlet class when the servlet is instantiated for the first time.
Here’s the full source code of the package net.codejava.javaee.bookstore; import tag to determine whether this object is available or not. The JDBC connection information will be read from Servlet’s context parameters.
Name the project as Bookstore: Remember to choose Target runtime as Apache Tomcat v8.0 and Dynamic web module version as 3.1 (this is the Java servlet version). Then convert this project to a Maven project by right click on the project, select Configure As you can see, the dependencies here are for Servlet, JSP, JSTL and My SQL connector Java (a JDBC driver for My SQL). The following is code of the object will be passed from a servlet which we will create later.
And remember to create a Java package for the project, here we use the package name As you can see, this class has 4 fields according to 4 columns in the table book in database: id, title, author and price. On running, this page looks something like this: As you can see, on this page we have two hyperlinks at the top menu for creating a new book (Add New Book) and showing all books (List All Books). Http Servlet Response; /** * Controller * This servlet acts as a page controller for the application, handling all * requests from the user.
The do Get method also converts the date into a format that is easy for the end user to modify and it also maps the book into request scope as follows: In the model 2 architecture, the Servlet tier prepares the form data before a form loads to be rendered and edited correctly.
In this Java tutorial, we’re going to help you understand the process of coding a basic Java web application that manages a collection of books with the basic feature: list, insert, update, delete (or CURD operations - Create, Update, Read and Delete). * @author */ public class Book DAO For detailed instructions on CRUD operations with JDBC, see JDBC Tutorial: SQL Insert, Select, Update, and Delete Examples.
The application looks something like this: You will learn to how to build this application using the following technologies: CREATE DATABASE 'Bookstore'; USE Bookstore; CREATE TABLE `book` ( `book_id` int(11) NOT NULL AUTO_INCREMENT, `title` varchar(128) NOT NULL, `author` varchar(45) NOT NULL, `price` float NOT NULL, PRIMARY KEY (`book_id`), UNIQUE KEY `book_id_UNIQUE` (`book_id`), UNIQUE KEY `title_UNIQUE` (`title`) ) ENGINE=Inno DB AUTO_INCREMENT=11 DEFAULT CHARSET=latin1 Dynamic Web Project to create a new Java dynamic web project. Next, create a JSP page for displaying all books from the database.
A CRUD (Create, Read, Update and Delete) application is the most important application for any project development. Create "user905" table in Oracle Database with auto incrementing id using sequence.
There are 5 fields in it: id, name, password, email and country.
On running, this page shows new form like this: And on editing mode: We’ll see how to connect the DAO class with the JSP pages based on user’s requests in the next section: creating the servlet class. It’s time to deploy and test the application to see how it works.