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 bookShelf;
public LibrarySessionBean(){
bookShelf = new ArrayList();
}
public void addBook(String bookName) {
bookShelf.add(bookName);
}
public List 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
1. Add Book
2. 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 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 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
1. Add Book
2. Exit
Enter Choice: 1
Enter book name: Learn Java
**********************
Welcome to Book Store
**********************
Options
1. Add Book
2. Exit
Enter Choice: 2
Book(s) entered so far: 1
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。
(編輯：雷林鵬 來源：網絡|侵刪)