创建应用程序（Create Application）

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2023-12-01

要创建一个简单的EJB模块，我们将使用NetBeans“新建项目”向导。在下面给出的示例中，我们将创建一个名为Component的EJB模块项目。

创建项目

在NetBeans IDE中，选择“ File 》 New Project 》 。您将看到以下屏幕

在类别Java EE下选择项目类型，将项目类型选择为EJB Module 。单击“ Next 》按钮。您将看到以下屏幕。

输入项目名称和位置。单击“ Next 》按钮。您将看到以下屏幕。

选择Server作为JBoss Application Server 。单击Finish按钮。您将看到NetBeans创建的以下项目。

创建一个示例EJB

要创建一个简单的EJB，我们将使用NetBeans“新建”向导。在下面给出的示例中，我们将在EjbComponent项目下创建名为librarySessionBean的无状态EJB类。

在项目资源管理器窗口中选择项目EjbComponent并右键单击它。选择， New 》 Session Bean 。您将看到New Session Bean向导。

输入会话bean名称和包名称。单击Finish按钮。您将看到NetBeans创建的以下EJB类。

LibrarySessionBean - 无状态会话bean
LibrarySessionBeanLocal - 会话bean的本地接口

我正在将本地接口更改为远程接口，因为我们将在基于控制台的应用程序中访问我们的EJB。远程/本地接口用于公开EJB必须实现的业务方法。

LibrarySessionBeanLocal重命名为LibrarySessionBeanRemote，LibrarySessionBean实现LibrarySessionBeanRemote接口。

LibrarySessionBeanRemote

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

LibrarySessionBean

package cn.xnip.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;
   }
}

构建项目 (Build the Project)

在Project Explorer窗口中选择EjbComponent项目。
右键单击它以打开上下文菜单。
Select clean and build.

您将在NetBeans控制台输出中看到以下输出。

ant -f C:\\EJB\\EjbComponent clean dist
init:
undeploy-clean:
deps-clean:
Deleting directory C:\EJB\EjbComponent\build
Deleting directory C:\EJB\EjbComponent\dist
clean:
init:
deps-jar:
Created dir: C:\EJB\EjbComponent\build\classes
Copying 3 files to C:\EJB\EjbComponent\build\classes\META-INF
Created dir: C:\EJB\EjbComponent\build\empty
Created dir: C:\EJB\EjbComponent\build\generated-sources\ap-source-output
Compiling 2 source files to C:\EJB\EjbComponent\build\classes
warning: [options] bootstrap class path not set in conjunction with -source 1.6
Note: C:\EJB\EjbComponent\src\java\com\xnip\stateless
\LibraryPersistentBean.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
1 warning
compile:
library-inclusion-in-archive:
Created dir: C:\EJB\EjbComponent\dist
Building jar: C:\EJB\EjbComponent\dist\EjbComponent.jar
dist:
BUILD SUCCESSFUL (total time: 3 seconds)

启动Application Server

在Services in Services窗口中选择JBoss应用程序服务器。
右键单击它以打开上下文菜单。
选择开始。

您将在NetBeans中看到以下输出，在JBoss Application Server下输出。

Calling C:\jboss-5.1.0.GA\bin\run.conf.bat
=========================================================================
   JBoss Bootstrap Environment
   JBOSS_HOME: C:\jboss-5.1.0.GA
   JAVA: C:\Program Files (x86)\Java\jdk1.6.0_21\bin\java
   JAVA_OPTS: -Dprogram.name=run.bat -Xms128m -Xmx512m -server
   CLASSPATH: C:\jboss-5.1.0.GA\bin\run.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

部署项目

在Project Explorer窗口中选择EjbComponent项目。
右键单击它以打开上下文菜单。
选择“部署”。

您将在NetBeans控制台输出中看到以下输出。

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:\EJB\EjbComponent\dist\EjbComponent.jar
dist-directory-deploy:
pre-run-deploy:
Checking data source definitions for missing JDBC drivers...
Distributing C:\EJB\EjbComponent\dist\EjbComponent.jar to [org.jboss.deployment.spi.LocalhostTarget@1e4f84ee]
Deploying C:\EJB\EjbComponent\dist\EjbComponent.jar
Application Deployed
Operation start started
Operation start completed
post-run-deploy:
run-deploy:
run:
BUILD SUCCESSFUL (total time: 2 seconds)

JBoss应用服务器日志输出

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-cn.xnip.stateless.LibrarySessionBeanRemote
16:30:01,281 INFO  [JBossASKernel]    Class:cn.xnip.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: cn.xnip.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-cn.xnip.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: cn.xnip.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-cn.xnip.stateless.LibrarySessionBeanRemote - EJB3.x Remote Business Interface

创建客户端以访问EJB

在NetBeans IDE中，选择“ File 》 New Project 》 。
在Java类别下选择项目类型，将项目类型选择为Java Application 。单击“下一步”按钮
输入项目名称和位置。单击“ Finish 》按钮。我们选择了名字为EjbTester。
在Project explorer窗口中右键单击项目名称。选择properties 。
使用compile选项卡中的“ Add Project按钮Add Project先前在库下创建的EJB组件项目
使用compile选项卡中的Add jar/folder按钮添加jboss库。 Jboss库可以位于“jboss安装文件夹”“客户端文件夹中。

在项目下创建jndi.properties说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

在它下面创建包cn.xnip.test和EJBTester.java类。

EJBTester.java

package cn.xnip.test;
import cn.xnip.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 \n1. Add Book\n2. Exit \nEnter 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());
         }
      }
   }  
}

运行客户端以访问EJB

在项目资源管理器中找到EJBTester.java。右键单击EJBTester类并选择run file 。

在Netbeans控制台中验证以下输出。

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)

在接下来的章节中，我们将介绍这个完整EJB应用程序的多个方面。