EclipseLink – 16 – Servlet & JSP & JPA & Bootstrap
Merhaba Arkadaslar
Onceki bolumlerde Java SE uygulamalari gerceklestirdik. Bu bolumde JPA uygulamamizi bir Servlet&JSP ile yapacagiz. Bu bolumde isin icine bir miktar Bootstrap da katacagiz.
Kullanacagimiz teknolojiler ;
- Servlet&JSP
- JPA/EclipseLink
- Oracle/MySQL
- Apache Tomcat
- Bootstrap
Burada Bootstrap’i incelemeyecegiz zaten benim de pek bildigim bir konu degil 🙂
Ufak bir arastirma ile form icin ve datatable icin kullanabilecegim linkleri buldum. Bu konuda onerebileceginiz siteler varsa paylasirsaniz sevinirim.
Simdi biz uygulamamiza donelim. Oncelikle Dynamic Web Project olusturdum ve Maven Project olarak convert ediyorum. Burada bu konulardan bahsetmeyecegim Maven ve Servlet&JSP yazilarimda ilgili bilgileri bulabilirsiniz.
pom.xml
Onceki bolumlerde kullandigimiz pom.xml dosyasina benzer sekilde ayni dosyayi kullanabiliriz.
Burada ek olarak JSTL tag’i kullanacagimiz icin ilgili jar’lar icin dependency tanimlarini da ekleyelim.
... <repositories> <repository> <id>codelds</id> <url>https://code.lds.org/nexus/content/groups/main-repo</url> </repository> </repositories> <!-- Last Update Date : 22.09.2018 --> <dependencies> <!-- https://mvnrepository.com/artifact/org.eclipse.persistence/org.eclipse.persistence.jpa --> <dependency> <groupId>org.eclipse.persistence</groupId> <artifactId>org.eclipse.persistence.jpa</artifactId> <version>2.7.3</version> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.12</version> </dependency> <dependency> <groupId>com.oracle</groupId> <artifactId>ojdbc6</artifactId> <version>11.2.0.3</version> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet.jsp.jstl/jstl-api --> <dependency> <groupId>javax.servlet.jsp.jstl</groupId> <artifactId>jstl-api</artifactId> <version>1.2</version> </dependency> <!-- https://mvnrepository.com/artifact/org.apache.taglibs/taglibs-standard-impl --> <dependency> <groupId>org.apache.taglibs</groupId> <artifactId>taglibs-standard-impl</artifactId> <version>1.2.5</version> </dependency> <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>4.0.1</version> </dependency> </dependencies> ...
persistence.xml
persistence.xml dosyamiz yine META-INF klasorunde yer alacak. Bunun icin yeni bir source folder olusturabiliriz.
... <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd" version="2.1"> <persistence-unit name="EmployeePersistenceUnit" transaction-type="RESOURCE_LOCAL"> <class>model.Employee</class> <properties> <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" /> <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/jpa.schema" /> <property name="javax.persistence.jdbc.user" value="root" /> <property name="javax.persistence.jdbc.password" value="123456" /> <property name="eclipselink.ddl-generation" value="drop-and-create-tables" /> <!-- <property name="javax.persistence.jdbc.driver" value="oracle.jdbc.driver.OracleDriver" /> <property name="javax.persistence.jdbc.url" value="jdbc:oracle:thin:@localhost:1520:xe" /> <property name="javax.persistence.jdbc.user" value="Levent" /> <property name="javax.persistence.jdbc.password" value="123456" /> --> </properties> </persistence-unit> </persistence> ...
Model
Oncelikle model sinifimizi olusturalim , onceki bolumlerde kullandigimiz Employee siniflarina benzer sekilde ;
Employee.java
package model;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
@Entity
public class Employee {
@Id
@GeneratedValue(strategy = GenerationType.TABLE)
private int id;
private String name;
private String surname;
private int salary;
public Employee() {
super();
}
public Employee(String name, String surname, int salary) {
super();
this.name = name;
this.surname = surname;
this.salary = salary;
}
//getters and setters
...
}
Java SE uygulalarimizda oldugu gibi EntityManagerFactory ‘u kendimiz olusturmamiz gereklidir. Burada basit olarak bir Servlet ornegi yaptigimiz icin @PersistenceContext ve @PersistenceUnit annotationlarini kullanamayiz.
EntityManagerFactory objemizi olusturalim ;
EntityManagerUtility.java
package utility;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
public class EntityManagerUtility {
private EntityManagerUtility() {
throw new AssertionError();
// Enforce noninstantiability with a private constructor
// Joshua Bloch , Effective Java Item 04
}
private static EntityManagerFactory entityManagerFactory = Persistence
.createEntityManagerFactory("EmployeePersistenceUnit");
public static EntityManager getEntityManager() {
return entityManagerFactory.createEntityManager();
}
}
Data Access Object (DAO)
Data Access Object (DAO) design pattern yapisina uygun olarak interface ve siniflarimizi olusturalim. Onceki orneklerimizde ayni siniflari kullanmistik.
EmployeeDAO.java
package dao;
import java.util.List;
import model.Employee;
public interface EmployeeDAO {
public Employee insertEmployee(Employee employee);
public Employee findEmployee(int id);
public List<Employee> findAllEmployees();
public void removeEmployee(int id);
}
EmployeeDAOImpl.java
package dao;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.TypedQuery;
import model.Employee;
import utility.EntityManagerUtility;
public class EmployeeDAOImpl implements EmployeeDAO {
@Override
public Employee insertEmployee(Employee employee) {
EntityManager entityManager = EntityManagerUtility.getEntityManager();
entityManager.getTransaction().begin();
entityManager.persist(employee);
entityManager.getTransaction().commit();
entityManager.close();
return employee;
}
@Override
public Employee findEmployee(int id) {
EntityManager entityManager = EntityManagerUtility.getEntityManager();
Employee employee = entityManager.find(Employee.class, id);
entityManager.close();
return employee;
}
@Override
public List<Employee> findAllEmployees() {
EntityManager entityManager = EntityManagerUtility.getEntityManager();
TypedQuery<Employee> query = entityManager.createQuery("Select e from Employee e", Employee.class);
List<Employee> employees = query.getResultList();
entityManager.close();
return employees;
}
@Override
public void removeEmployee(int id) {
EntityManager entityManager = EntityManagerUtility.getEntityManager();
Employee employee = entityManager.find(Employee.class, id);
if (employee != null) {
entityManager.getTransaction().begin();
entityManager.remove(employee);
entityManager.getTransaction().commit();
entityManager.close();
}
}
}
Service
Service Layer icin sinifimizi yazalim , Service Layer’dan DAO sinifimiza ulasim sagliyoruz.
EmployeeService.java
package service;
import java.util.List;
import model.Employee;
public interface EmployeeService {
public Employee insertEmployee(Employee employee);
public Employee findEmployee(int id);
public List<Employee> findAllEmployees();
public void removeEmployee(int id);
}
EmployeeServiceImpl.java
package service;
import java.util.List;
import model.Employee;
import dao.EmployeeDAO;
import dao.EmployeeDAOImpl;
public class EmployeeServiceImpl implements EmployeeService {
private EmployeeDAO employeeDAO;
public EmployeeServiceImpl() {
employeeDAO = new EmployeeDAOImpl();
}
@Override
public Employee insertEmployee(Employee employee) {
return employeeDAO.insertEmployee(employee);
}
@Override
public Employee findEmployee(int id) {
return employeeDAO.findEmployee(id);
}
@Override
public List findAllEmployees() {
return employeeDAO.findAllEmployees();
}
@Override
public void removeEmployee(int id) {
employeeDAO.removeEmployee(id);
}
}
Controller
Simdi de Servlet sinifimizi yazalim.
@WebServlet annotation ile Servlet tanimini yapabiliriz. doPost metodunu inceleyecek olursak kullanicinin forma girdigi name, surname ve salary bilgilerini aliyoruz ve kayit olarak tabloya ekliyoruz. Daha sonrasinda tum kayitlari getirip request dispatch ediyoruz.
doGet metodunda ise id bilgisini aliyoruz ve kaydi sildikten sonra tekrar tum kayitlari getirip request dispatch ediyoruz.
Yani doPost metodunu kayit eklemek icin doGet metodunu kayit silmek icin kullaniyoruz. Tabi istersek farkli Servlet’ler kullanabiliriz.
EmployeeController.java
package controller;
import java.io.IOException;
import java.util.List;
import javax.servlet.RequestDispatcher;
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 service.EmployeeService;
import service.EmployeeServiceImpl;
import model.Employee;
@WebServlet("/employeeController")
public class EmployeeController extends HttpServlet {
private static final long serialVersionUID = 1L;
private final EmployeeService employeeService = new EmployeeServiceImpl();
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String employeeName = req.getParameter("name");
String employeeSurname = req.getParameter("surname");
int employeeSalary = Integer.parseInt(req.getParameter("salary"));
Employee employee = new Employee(employeeName, employeeSurname, employeeSalary);
employeeService.insertEmployee(employee);
List<Employee> allEmployees = employeeService.findAllEmployees();
req.setAttribute("allEmployees", allEmployees);
RequestDispatcher dispatcher = req.getRequestDispatcher("employee.jsp");
dispatcher.forward(req, resp);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
int employeeId = Integer.parseInt(req.getParameter("employeeId"));
employeeService.removeEmployee(employeeId);
List<Employee> allEmployees = employeeService.findAllEmployees();
req.setAttribute("allEmployees", allEmployees);
RequestDispatcher dispatcher = req.getRequestDispatcher("employee.jsp");
dispatcher.forward(req, resp);
}
}
View
Yazinin basinda belirttigim gibi ornekte bootstrap kullandim. Isin Bootstrap css kismini bir koseye birakacak olursak basit olarak bir form olusturdum ve submit edildiginde HTTP POST istegi EmployeeController doPost tarafindan yakalanacak.
Bootstrap icin gerekli js ve css dosyalarimi WebContent/resources dizininde ilgili dosyalarda yer alacaktir.
.... <script src="resources/js/bootstrap.min.js"></script> <link href="resources/css/bootstrap.min.css" rel="stylesheet"> ... <form class="form-horizontal" action="employeeController" method="POST"> ...
c:forEach ile allEmployees request attribute’u yazdiralim. JSTL tag’i kullanabilmek icin oncelikle @taglib directive’i eklememiz gerektigini unutmayalim. Tabi unun icin pom.xml dosyamiza ilgili dependency tanimlarini eklememiz gereklidir.
employeeId bilgisini linke parametre olarek ekliyoruz. Boylece hangi Employee kaydi silinecek belirtmis oluruz.
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
...
...
<c:forEach items="${allEmployees}" var="employee">
<tr>
<td><c:out value="${employee.name}" /></td>
<td><c:out value="${employee.surname}" /></td>
<td><c:out value="${employee.salary}" /></td>
<td><a href="employeeController?employeeId=${employee.id}"
class="btn btn-danger" type="button">Button</a></td>
</tr>
</c:forEach>
Run Application
employee.jsp dosyamizi calistiralim ve forma veri girerek yeni kayitlar ekleyelim.
Daha sonrasinda Delete butonu ile ilgili kaydi silebiliriz.
Bu ornek daha da gelistirilebilir , update islemi ve validasyon islemi yapilabilir. Ornek olmasi acisindan bizim icin simdilik yeterli olacaktir.
Github source code :
injavawetrust.servlet.jpa
Yazimi burada sonlandiriyorum.
Herkese Bol Javali Gunler dilerim.
Be an oracle man , import java.*;
Levent Erguder
OCP, Java SE 6 Programmer
OCE, Java EE 6 Web Component Developer
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