Учебное пособие по JSP 2.2 и сервлетам 3.0 с помощью контейнера сервлетов со смолой OpenSource: часть 1

Контейнер для серво с открытым исходным кодом

Контейнер сервлетов веб-профиля Java EE

Необязательно: Начало работы Eclipse Java EE IDE

Сначала перейдите по ссылке, чтобы получить Eclipse для Java EE: Руководство по установке Eclipse для Java EE Indigo или выше .

Используя Eclipse Indigo или выше

Установите плагин Resin (легкий, быстрый, простой в использовании сервер Java EE 6 Web Profile):

1. Зайдите в меню Файл -> Новый проект -> Динамический веб-проект
2. В новом динамическом веб-диалоге проекта-> Новая среда выполнения …
3. В новом диалоговом окне времени выполнения -> Загрузить дополнительные серверные адаптеры -> Выбрать смолу (веб-профиль Java EE) 4.0.x



4. (Click Next and Ok until it installs Resin runtime)



5. (Eclipse needs to restart)

Bill Digman is a Java EE / Servlet enthusiast and Open Source enthusiast who loves working with Caucho’s Resin Servlet Container, a Java EE Web Profile Servlet Container.

Caucho’s Resin OpenSource Servlet Container

Java EE Web Profile Servlet Container

Setup new Web Project in Eclipse

1. File -> New Project -> Dynamic Web Project



2. In New Dynamic Web Project Dialog-> New Runtime…->Select Resin->Check create local server checkbox
3. Step 2 of New Runtime…->Click Download and Install (you only have to do this once)
4. Fill out project name etc. (bookstore).



5. (Click Next and Ok until you are done)

Resources

For each cookbook of the tutorial our goal is to provide a slide deck, and video to accompany the wiki page. The idea is between the three resources (wiki, slide deck and video or videos), you might find what you are looking for if you missed something. I don’t recommend skipping this slidedeck as it is usually done after the wiki and I catch stuff (concepts) that I missed in the text.

• Slide Deck | Java EE Servlet/JSP Tutorial- Cookbook 1
• YouTube Video | Java EE Servlets/JSP Tutorial — Cookbook 1 — Part 1
• YouTube Video | Java EE Servlets/JSP Tutorial — Cookbook 1 — Part 2

Bill Digman is a Java EE / Servlet enthusiast and Open Source enthusiast who loves working with Caucho’s Resin Servlet Container, a Java EE Web Profile Servlet Container.

Caucho’s Resin OpenSource Servlet Container

Java EE Web Profile Servlet Container

What is going to be in the project

The project will be a basic CRUD (create read update delete) listing for a BookStore.

Creating model and Repository objects for books

Create a new Java class as follows:

Eclipse: Right Click «Java Resources» in Project Explorer -> New -> Class -> Package com.bookstore -> Class Name -> Book (That is the last time I will tell you how to create a class in Eclipse.)

Add title, description, price, pubDate and id properties, and the toString and cloneMe methods as follows:

Book model class

package com.bookstore;

import java.math.BigDecimal;
import java.util.Date;

public class Book implements Cloneable {

	private String title;
	private String description;
	private BigDecimal price;
	private Date pubDate;
	private String id;

	public Book(String id, String title, String description, BigDecimal price, Date pubDate) {
		this.id = id;
		this.title = title;
		this.description = description;
		this.price = price;
		this.pubDate = pubDate;

	}

	public Book () {

	}

	public String getTitle() {
		return title;

	}

	public void setTitle(String title) {
		this.title = title;

	}

	public String getDescription() {
		return description;

	}

	public void setDescription(String description) {
		this.description = description;

	}

	public BigDecimal getPrice() {
		return price;

	}

	public void setPrice(BigDecimal price) {
		this.price = price;

	}

	public Date getPubDate() {
		return pubDate;

	}

	public void setPubDate(Date pubDate) {
		this.pubDate = pubDate;

	}

	public String getId() {
		return id;

	}

	public void setId(String id) {
		this.id = id;

	}

	public Book cloneMe() {
		try {
			return (Book) super.clone();
		} catch (CloneNotSupportedException e) {
			return null;
		}
	}

	@Override
	public String toString() {
		return "Book [title=" + title + ", description=" + description
			+ ", price=" + price + ", pubDate=" + pubDate + ", id=" + id
			+ "]";
	}



}

Bill Digman is a Java EE / Servlet enthusiast and Open Source enthusiast who loves working with Caucho’s Resin Servlet Container, a Java EE Web Profile Servlet Container.

Caucho’s Resin OpenSource Servlet Container

Java EE Web Profile Servlet Container

Are you new to Java?

If you are new to Java and the above seems foreign to you, I suggest you read up on Java a bit Official Java tutorial. Read the first three trails (Getting Started, Learning the Java Language and Essential Java Classes), and then skip ahead to Java Beans. Skimming is ok. If you have programmed before, most things you will pick up on your own.

Reminder: The methods public String getId() and public void setId(String id) would define a property called id.

This first step in this tutorial is not going to actually talk to a database or use JDBC. For now, we are just going to use the collection API to create a Repository object (some people call this a DAO — data access object). The Repository object encapsulates how an object gets persisted, queried and updated (CRUD operations).

We know we are going to later use JDBC/RDBMS (MySQL), JTA/RDBMS, JCache, MongoDB, etc. instead of the collection API so let’s define an interface so we can swap these in quickly as we get to these tutorials. The interface will define the contract with our Repository object that we can later swap out with other implementations.

Eclipse: Right Click «Java Resources» in Project Explorer -> New -> Interface -> Package = com.bookstore -> Class Name = Book -> Click Finish. (That is the last time I will tell you how to create an interface in Eclipse.)

BookRepository interface

package com.bookstore;

import java.util.List;

public interface BookRepository {
	Book lookupBookById(String id);

	void addBook(String title, String description,
		String price, String pubDate);

	void updateBook(String id, String title,
		String description, String price, String pubDate);

	void removeBook(String id);


	List<Book> listBooks();

}

Bill Digman is a Java EE / Servlet enthusiast and Open Source enthusiast who loves working with Caucho’s Resin Servlet Container, a Java EE Web Profile Servlet Container.

Caucho’s Resin OpenSource Servlet Container

Контейнер сервлетов веб-профиля Java EE

Затем создайте класс с именем BookRepositoryImpl следующим образом (не изучайте его слишком много, если не хотите, он просто имитирует доступ к базе данных):

package com.bookstore;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.math.BigDecimal;

import javax.enterprise.context.ApplicationScoped;

@ApplicationScoped
public class BookRepositoryImpl implements BookRepository {

	private SimpleDateFormat dateFormat = new SimpleDateFormat("MM/dd/yyyy");
	private int count;
	private Map<String, Book> idToBookMap = new HashMap<String, Book>();

	public BookRepositoryImpl() {
		synchronized (this) {
			books(book("War and Peace", "blah blah blah", "5.50", "5/29/1970"),
				book("Pride and Prejudice", "blah blah blah", "5.50", "5/29/1960"),
				book("book1", "blah blah blah", "5.50", "5/29/1960"),
				book("book2", "blah blah blah", "5.50", "5/29/1960"),
				book("book3", "blah blah blah", "5.50", "5/29/1960"),
				book("book4", "blah blah blah", "5.50", "5/29/1960"),
				book("book5", "blah blah blah", "5.50", "5/29/1960"),
				book("book6", "blah blah blah", "5.50", "5/29/1960"),
				book("book7", "blah blah blah", "5.50", "5/29/1960"),
				book("book8", "blah blah blah", "5.50", "5/29/1960"),
				book("book9", "blah blah blah", "5.50", "5/29/1960"),
				book("Java for dummies", "blah blah blah", "1.99", "5/29/1960"));
		}
	}

	private Book book(String title, String description, String aPrice,
			String aPubDate) {

		Date pubDate = null;
		BigDecimal price = null;

		try {
			price = new BigDecimal(aPrice);
		}catch (Exception ex) {
		}

		try {
			pubDate = dateFormat.parse(aPubDate);
		}catch (Exception ex) {
		}

		return new Book("" + (count++), title, description, price, pubDate);

	}

	private void books(Book... books) {
		for (Book book : books) {
			doAddBook(book);
		}
	}

	private void doAddBook(Book book) {
		synchronized (this) {
			this.idToBookMap.put(book.getId(), book);
		}
	}

	@Override
	public Book lookupBookById(String id) {
		synchronized (this) {
			return this.idToBookMap.get(id).cloneMe();
		}
	}

	@Override
	public void addBook(String title, String description, String price,
			String pubDate) {
		doAddBook(book(title, description, price, pubDate));
	}

	@Override
	public void updateBook(String id, String title, String description,
			String price, String pubDate) {
		Book book = book(title, description, price, pubDate);
		synchronized (this) {
			book.setId(id);
			this.idToBookMap.put(id, book);
		}
	}

	private List<Book> doListBooks() {
		List<Book> books;
		synchronized (this) {

			books = new ArrayList<Book>(this.idToBookMap.size());
			for (Book book : this.idToBookMap.values()) {
				books.add(book.cloneMe());
			}
		}
		return books;
	}

	public List<Book> listBooks() {

		List<Book> books = doListBooks();

		Collections.sort(books, new Comparator<Book>() {
			public int compare(Book bookA, Book bookB) {
				return bookA.getId().compareTo(bookB.getId());
			}
		});
		return books;
	}

	@Override
	public void removeBook(String id) {
		synchronized(this) {
			this.idToBookMap.remove(id);
		}
	}
}

Этот BookRepositoryImpl является довольно простым классом. Это в значительной степени основано на API коллекций. Вы можете узнать больше информации об API коллекций Java в этом учебном курсе . Полное обсуждение API коллекции выходит за рамки этого учебного пособия, и этот класс предназначен в основном только для тестирования, позже мы будем хранить элементы в базах данных и тому подобное.

import javax.enterprise.context.ApplicationScoped;

@ApplicationScoped
public class BookRepositoryImpl implements BookRepository {

package com.bookstore.web;

import java.io.IOException;


import javax.inject.Inject;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.bookstore.BookRepository;

@WebServlet("/book/")
public class BookListServlet extends HttpServlet {

	@Inject
	private BookRepository bookRepo;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setAttribute("books", bookRepo.listBooks());
		getServletContext().getRequestDispatcher("/WEB-INF/pages/book-list.jsp").forward(request, response);
	}

}

...

@WebServlet("/book/")
public class BookListServlet extends HttpServlet {

	@Inject
	private BookRepository bookRepo;

...

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setAttribute("books", bookRepo.listBooks());
		getServletContext().getRequestDispatcher("/WEB-INF/pages/book-list.jsp").forward(request, response);
	}

		getServletContext().getRequestDispatcher("/WEB-INF/pages/book-list.jsp").forward(request, response);

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix ="c" %>
<!DOCTYPE HTML>

<html>
<head>
<title>Book listing</title>
</head>
<body>


<table>
	<tr>
		<th>Title</th>
		<th>Description</th>
		<th>Price</th>
		<th>Publication Date</th>
		</tr>

	<c:forEach var="book" items="${books}">
		<tr>
			<td>${book.title}</td>
			<td>${book.description}</td>
			<td>${book.price}</td>
			<td>${book.pubDate}</td>
		</tr>
	</c:forEach>
</table>

</body>
</html>

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix ="c" %>

	<c:forEach var="book" items="${books}">
		<tr>
			<td>${book.title}</td>
			<td>${book.description}</td>
			<td>${book.price}</td>
			<td>${book.pubDate}</td>
		</tr>
	</c:forEach>

//doGet method
		request.setAttribute("books", bookRepo.listBooks());

$ pwd
~/workspace/javaee-tutorial/notes/src/META-INF

$ touch beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://java.sun.com/xml/ns/javaee"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/beans_1_0.xsd">
</beans>