EJB創建應用

要創建一個簡單的EJB模塊，我們這裏使用NetBeans「 New project」嚮導。在下面的例子中，我們將創建一個名爲「 Component」的EJB模塊項目。

創建項目

在NetBeans IDE中，選擇File > New Project >. 可以看到如下圖.

在類別中選擇項目類型，Java EE的EJB模塊項目類型。點擊Next>按鈕，你會看到以下的畫面。

輸入項目的名稱和位置。點擊Next>按鈕。你會看到以下的畫面。

選擇服務器爲JBoss應用服務器。單擊「Finish」按鈕。你會看到以下由NetBeans創建的項目。

創建一個簡單的EJB

要創建一個簡單的EJB，我們將使用NetBeans「New」嚮導。在下面的例子中，我們將在EjbComponent項目下創建一個無狀態EJB類名爲librarySessionBean。

在項目資源管理器窗口中選擇項目EjbComponent，右鍵單擊它。選擇New > Session Bean。您將看到新的會話Bean嚮導。

輸入會話bean的名稱和包名。單擊「Finish 」按鈕。你會看到以下由NetBeans創建的EJB類。

LibrarySessionBean - 無狀態會話bean
LibrarySessionBeanLocal - 本地接口的會話bean

要改變本地接口，我們要一個基於控制檯的應用程序訪問我們的EJB遠程接口。遠程/本地接口用於公開一個EJB的業務方法實現。

LibrarySessionBeanLocal更名爲LibrarySessionBeanRemote和LibrarySessionBean實現LibrarySessionBeanRemote接口。

LibrarySessionBeanRemote

package com.tutorialspoint.stateless; import java.util.List; import javax.ejb.Remote; @Remote public interface LibrarySessionBeanRemote { void addBook(String bookName); List getBooks(); }

LibrarySessionBean

package com.tutorialspoint.stateless; import java.util.ArrayList; import java.util.List; import javax.ejb.Stateless; @Stateless public class LibrarySessionBean implements LibrarySessionBeanRemote { List<String> bookShelf; public LibrarySessionBean(){ bookShelf = new ArrayList<String>(); } public void addBook(String bookName) { bookShelf.add(bookName); } public List<String> getBooks() { return bookShelf; } }

構建項目

在Project Explorer窗口中選擇EjbComponent項目。
右鍵點擊它來打開上下文菜單。
選擇 clean and build。

在NetBeans控制檯輸出，你會看到以下的輸出。

ant -f C:\EJB\EjbComponent clean dist
init:
undeploy-clean:
deps-clean:
Deleting directory C:EJBEjbComponentuild
Deleting directory C:EJBEjbComponentdist
clean:
init:
deps-jar:
Created dir: C:EJBEjbComponentuildclasses
Copying 3 files to C:EJBEjbComponentuildclassesMETA-INF
Created dir: C:EJBEjbComponentuildempty
Created dir: C:EJBEjbComponentuildgenerated-sourcesap-source-output
Compiling 2 source files to C:EJBEjbComponentuildclasses
warning: [options] bootstrap class path not set in conjunction with -source 1.6
Note: C:EJBEjbComponentsrcjavacom utorialspointstateless
LibraryPersistentBean.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 warning
compile:
library-inclusion-in-archive:
Created dir: C:EJBEjbComponentdist
Building jar: C:EJBEjbComponentdistEjbComponent.jar
dist:
BUILD SUCCESSFUL (total time: 3 seconds)

啓動應用程序服務器

服務器在服務窗口下選擇JBoss應用服務器。
右鍵點擊它來打開上下文菜單。
選擇start。

你會看到下面的輸出在NetBeans中JBoss應用服務器下的輸出。

Calling C:jboss-5.1.0.GAin
un.conf.bat
=========================================================================

JBoss Bootstrap Environment

JBOSS_HOME: C:jboss-5.1.0.GA

JAVA: C:Program Files (x86)Javajdk1.6.0_21injava

JAVA_OPTS: -Dprogram.name=run.bat -Xms128m -Xmx512m -server

CLASSPATH: C:jboss-5.1.0.GAin
un.jar

=========================================================================

16:25:50,062 INFO [ServerImpl] Starting JBoss (Microcontainer)...
16:25:50,062 INFO [ServerImpl] Release ID: JBoss [The Oracle] 5.1.0.GA (build: SVNTag=JBoss_5_1_0_GA date=200905221634)
...

16:26:40,420 INFO [TomcatDeployment] deploy, ctxPath=/admin-console
16:26:40,485 INFO [config] Initializing Mojarra (1.2_12-b01-FCS) for context '/admin-console'
16:26:42,362 INFO [TomcatDeployment] deploy, ctxPath=/
16:26:42,406 INFO [TomcatDeployment] deploy, ctxPath=/jmx-console
16:26:42,471 INFO [Http11Protocol] Starting Coyote HTTP/1.1 on http-127.0.0.1-8080
16:26:42,487 INFO [AjpProtocol] Starting Coyote AJP/1.3 on ajp-127.0.0.1-8009
16:26:42,493 INFO [ServerImpl] JBoss (Microcontainer) [5.1.0.GA (build: SVNTag=JBoss_5_1_0_GA date=200905221634)] Started in 52s:427ms

部署項目

在Project Explorer窗口中選擇EjbComponent項目。
右擊它，打開上下文菜單。
選擇 Deploy.

在NetBeans控制檯輸出，你會看到下面的輸出。

ant -f C:\EJB\EjbComponent -DforceRedeploy=true -Ddirectory.deployment.supported=false -Dnb.wait.for.caches=true run
init:
deps-jar:
compile:
library-inclusion-in-archive:
Building jar: C:EJBEjbComponentdistEjbComponent.jar
dist-directory-deploy:
pre-run-deploy:
Checking data source definitions for missing JDBC drivers...
Distributing C:EJBEjbComponentdistEjbComponent.jar to [org.jboss.deployment.spi.LocalhostTarget@1e4f84ee]
Deploying C:EJBEjbComponentdistEjbComponent.jar
Applicaton Deployed
Operation start started
Operation start completed
post-run-deploy:
run-deploy:
run:
BUILD SUCCESSFUL (total time: 2 seconds)

JBoss應用服務器的日誌輸出

16:30:00,963 INFO [DeployHandler] Begin start, [EjbComponent.jar]
...
16:30:01,233 INFO [Ejb3DependenciesDeployer] Encountered deployment AbstractVFSDeploymentContext@12038795{vfszip:/C:/jboss-5.1.0.GA/server/default/deploy/EjbComponent.jar/}
...
16:30:01,281 INFO [JBossASKernel] jndi:LibrarySessionBean/remote-com.tutorialspoint.stateless.LibrarySessionBeanRemote
16:30:01,281 INFO [JBossASKernel] Class:com.tutorialspoint.stateless.LibrarySessionBeanRemote
16:30:01,281 INFO [JBossASKernel] jndi:LibrarySessionBean/remote
16:30:01,281 INFO [JBossASKernel] Added bean(jboss.j2ee:jar=EjbComponent.jar,name=
LibrarySessionBean,service=EJB3) to KernelDeployment of: EjbComponent.jar
16:30:01,282 INFO [JBossASKernel] installing bean: jboss.j2ee:jar=EjbComponent.jar,name=BookMessageHandler,service=EJB3
16:30:01,282 INFO [JBossASKernel] with dependencies:
16:30:01,282 INFO [JBossASKernel] and demands:
16:30:01,282 INFO [JBossASKernel] jboss.ejb:service=EJBTimerService
...
16:30:01,283 INFO [EJB3EndpointDeployer] Deploy AbstractBeanMetaData@5497cb{name=jboss.j2ee:jar=EjbComponent.jar, name=LibrarySessionBean, service=EJB3_endpoint bean=org.jboss.ejb3.endpoint.deployers.impl.EndpointImpl properties=[container] constructor=null autowireCandidate=true}
...
16:30:01,394 INFO [SessionSpecContainer] Starting jboss.j2ee:jar=EjbComponent.jar,name=LibrarySessionBean,service=EJB3
16:30:01,395 INFO [EJBContainer] STARTED EJB: com.tutorialspoint.stateless.LibrarySessionBean ejbName: LibrarySessionBean
16:30:01,401 INFO [JndiSessionRegistrarBase] Binding the following Entries in Global JNDI:
LibrarySessionBean/remote - EJB3.x Default Remote Business Interface
LibrarySessionBean/remote-com.tutorialspoint.stateless.LibrarySessionBeanRemote - EJB3.x Remote Business Interface
16:30:02,723 INFO [SessionSpecContainer] Starting jboss.j2ee:jar=EjbComponent.jar,name=LibrarySessionBean,service=EJB3
16:30:02,723 INFO [EJBContainer] STARTED EJB: com.tutorialspoint.stateless.LibrarySessionBean ejbName: LibrarySessionBean
16:30:02,731 INFO [JndiSessionRegistrarBase] Binding the following Entries in Global JNDI:

LibrarySessionBean/remote - EJB3.x Default Remote Business Interface
LibrarySessionBean/remote-com.tutorialspoint.stateless.LibrarySessionBeanRemote - EJB3.x Remote Business Interface

創建客戶端訪問EJB

在NetBeans IDE中選擇 File > New Project >.
類別下選擇項目類型爲Java，項目類型爲Java應用程序的Java。點擊**Next>**按鈕。
輸入項目的名稱和位置。單擊「**Finish >**「按鈕。我們選擇名爲EjbTester。
右鍵點擊項目名稱(在Project explore窗口中)。選擇屬性properties。
添加EJB組件項目的庫使用「Add Project 」按鈕，在compile選項卡下創建的。
添加JBoss庫使用添加Add jar/folder按鈕，在compile選項卡。 Jboss的庫可以位於<JBOSS安裝文件夾>客戶端文件夾。

在工程中創建 jndi.properties說一個句話 EjbTester.

jndi.properties

java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces
java.naming.provider.url=localhost

創建包com.tutorialspoint.test和EJBTester.java類在下面。

EJBTester.java

package com.tutorialspoint.test; import com.tutorialspoint.stateless.LibrarySessionBeanRemote; import java.io.BufferedReader; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStreamReader; import java.util.List; import java.util.Properties; import javax.naming.InitialContext; import javax.naming.NamingException; public class EJBTester { BufferedReader brConsoleReader = null; Properties props; InitialContext ctx; { props = new Properties(); try { props.load(new FileInputStream("jndi.properties")); } catch (IOException ex) { ex.printStackTrace(); } try { ctx = new InitialContext(props); } catch (NamingException ex) { ex.printStackTrace(); } brConsoleReader = new BufferedReader(new InputStreamReader(System.in)); } public static void main(String[] args) { EJBTester ejbTester = new EJBTester(); ejbTester.testStatelessEjb(); } private void showGUI(){ System.out.println("**********************"); System.out.println("Welcome to Book Store"); System.out.println("**********************"); System.out.print("Options

Add Book
Exit
Enter Choice: "); } private void testStatelessEjb(){ try { int choice = 1; LibrarySessionBeanRemote libraryBean = (LibrarySessionBeanRemote)ctx.lookup("LibrarySessionBean/remote"); while (choice != 2) { String bookName; showGUI(); String strChoice = brConsoleReader.readLine(); choice = Integer.parseInt(strChoice); if (choice == 1) { System.out.print("Enter book name: "); bookName = brConsoleReader.readLine(); libraryBean.addBook(bookName); }else if (choice == 2) { break; } } List<String> booksList = libraryBean.getBooks(); System.out.println("Book(s) entered so far: " + booksList.size()); for (int i = 0; i < booksList.size(); ++i) { System.out.println((i+1)+". " + booksList.get(i)); } LibrarySessionBeanRemote libraryBean1 = (LibrarySessionBeanRemote)ctx.lookup("LibrarySessionBean/remote"); List<String> booksList1 = libraryBean1.getBooks(); System.out.println( "***Using second lookup to get library stateless object***"); System.out.println( "Book(s) entered so far: " + booksList1.size()); for (int i = 0; i < booksList1.size(); ++i) { System.out.println((i+1)+". " + booksList1.get(i)); } } catch (Exception e) { System.out.println(e.getMessage()); e.printStackTrace(); }finally { try { if(brConsoleReader !=null){ brConsoleReader.close(); } } catch (IOException ex) { System.out.println(ex.getMessage()); } } } }

運行客戶端訪問EJB

在project explorer中找到EJBTester.java。右鍵點擊上EJBTester類，並選擇「run file」。

在Netbeans控制檯驗證以下輸出。

run:
**********************
Welcome to Book Store
**********************
Options

Add Book
Exit
Enter Choice: 1
Enter book name: Learn Java
**********************
Welcome to Book Store
**********************
Options
Add Book
Exit
Enter Choice: 2
Book(s) entered so far: 1
Learn Java
***Using second lookup to get library stateless object***
Book(s) entered so far: 0
BUILD SUCCESSFUL (total time: 13 seconds)

在下面的章節中，我們將討論這個完整的EJB的多個層面應用程序。