EJB 3.0和Spring 2.5 ：在Spring中使用EJB 3.0 [转]

 Meera Subbarao说道

：EJB和Spring社区的开发者为什么总是贬低对方呢？我同时使用EJB和Spring，就像所有的开发者一样，我对于两者需要大量的XML设置非常头疼，但是从Java 5发布以来，XML配置已经用annotation来替代了。但是在使用了最新的Spring 2.5和EJB 3.0,我觉得它们是互相补充的关系，而非相互竞争关系。

许多开发者理解，Spring是由Spring Source创建的最常用的非标准框架，而EJB 3.0是一个由主要的JEE厂商创建的规格。我以前曾一起工作的同事更愿意使用标准规格，选择EJB 2.X现在迁移到EJB 3.0。也有开发者愿意使用Spring而拒绝EJB。但是没有任何东西阻止开发者同时使用Spring和EJB，对不对？在Spring的配置文件增加几行就能够在Spring中无缝使用EJB 3.0组件。

下面我将展示这个过程是多么简单，我们可以通过Spring的强大的依赖注入机制来注入Customer session bean。这个Customer session bean可以使用Entity Manager来进行创建/读写/删除操作。

 

1。创建一个简单的JPA Entity：

 

package com.ejb.domain;   
  
import java.io.Serializable;   
import javax.persistence.Column;   
import javax.persistence.Entity;   
import javax.persistence.Id;   
import javax.persistence.Table;   
  
/**  
 *  
 * @author meerasubbarao  
 */  
@Entity  
@Table(name = "CUSTOMER", catalog = "", schema = "ADMIN")   
public class Customer implements Serializable {   
    private static final long serialVersionUID = 1L;   
    @Id  
    @Column(name = "CUSTOMER_ID")   
    private Long customerId;   
    @Column(name = "FIRST_NAME")   
    private String firstName;   
    @Column(name = "LAST_NAME")   
    private String lastName;   
    @Column(name = "MIDDLE_NAME")   
    private String middleName;   
    @Column(name = "EMAIL_ID")   
    private String emailId;   
  
    public Customer() {   
    }   
  
    public Customer(Long customerId) {   
        this.customerId = customerId;   
    }   
  
    public Long getCustomerId() {   
        return customerId;   
    }   
  
    public void setCustomerId(Long customerId) {   
        this.customerId = customerId;   
    }   
  
    public String getFirstName() {   
        return firstName;   
    }   
  
    public void setFirstName(String firstName) {   
        this.firstName = firstName;   
    }   
  
    public String getLastName() {   
        return lastName;   
    }   
  
    public void setLastName(String lastName) {   
        this.lastName = lastName;   
    }   
  
    public String getMiddleName() {   
        return middleName;   
    }   
  
    public void setMiddleName(String middleName) {   
        this.middleName = middleName;   
    }   
  
    public String getEmailId() {   
        return emailId;   
    }   
  
    public void setEmailId(String emailId) {   
        this.emailId = emailId;   
    }   
  
  
}  

 

 

2.创建一个EJB 3.0 Session bean.

The Interface:

 

 

package com.ejb.service;   
  
import com.ejb.domain.Customer;   
import java.util.Collection;   
import javax.ejb.Remote;   
  
/**  
 *  
 * @author meerasubbarao  
 */  
@Remote  
public interface CustomerService {   
  
    Customer create(Customer info);   
  
    Customer update(Customer info);   
  
    void remove(Long customerId);   
  
    Collection<Customer> findAll();   
  
    Customer[] findAllAsArray();   
  
    Customer findByPrimaryKey(Long customerId);   
}  

 

 

 

The Implementation Class:

 

package com.ejb.service;   
  
import com.ejb.domain.Customer;   
import java.util.Collection;   
import javax.ejb.Stateless;   
import javax.jws.WebService;   
import javax.jws.soap.SOAPBinding;   
import javax.persistence.EntityManager;   
import javax.persistence.PersistenceContext;   
import javax.persistence.Query;   
import javax.jws.WebMethod;   
  
/**  
 *  
 * @author meerasubbarao  
 */  
@WebService(name = "CustomerService", serviceName = "CustomerService", targetNamespace = "urn:CustomerService")   
@SOAPBinding(style = SOAPBinding.Style.RPC)   
@Stateless(name = "CustomerService")   
public class CustomerServiceImpl implements CustomerService {   
  
    @PersistenceContext  
    private EntityManager manager;   
  
    @WebMethod  
    public Customer create(Customer info) {   
        this.manager.persist(info);   
        return info;   
    }   
  
    @WebMethod  
    public Customer update(Customer info) {   
        return this.manager.merge(info);   
    }   
  
    @WebMethod  
    public void remove(Long customerId) {   
        this.manager.remove(this.manager.getReference(Customer.class, customerId));   
    }   
  
    public Collection<Customer> findAll() {   
        Query query = this.manager.createQuery("SELECT c FROM Customer c");   
        return query.getResultList();   
    }   
  
    @WebMethod  
    public Customer[] findAllAsArray() {   
        Collection<Customer> collection = findAll();   
        return (Customer[]) collection.toArray(new Customer[collection.size()]);   
    }   
  
    @WebMethod  
    public Customer findByPrimaryKey(Long customerId) {   
        return (Customer) this.manager.find(Customer.class, customerId);   
    }   
  
     
}  

  

 

 

3.编译，打包，部署到一个应用服务器上。

我使用GlassFish，用缺省的持久化提供工具TopLink，persistence.xml文件配置如下：

 

 

<?xml version="1.0" encoding="UTF-8"?>  
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">  
  <persistence-unit name="SpringAndEJBPU" transaction-type="JTA">  
    <provider>oracle.toplink.essentials.PersistenceProvider</provider>  
    <jta-data-source>spring-ejb</jta-data-source>  
    <properties>  
      <property name="toplink.ddl-generation" value="drop-and-create-tables"/>  
    </properties>  
  </persistence-unit>  
</persistence>  

 

 

当你的应用部署以后，确认session bean JNDI名称，在 GlassFish 中，点击JNDI浏览工具按钮查看：

 

 

 

 

 

 

4: 测试无状态 Session beans.

 

 

 

 

 

5: 创建一个 Spring Bean.

创建一个CustomerManager 接口：

 

package com.spring.service;   
  
import com.ejb.domain.Customer;   
  
/**  
 *  
 * @author meerasubbarao  
 */  
public interface CustomerManager {   
  
    public void addCustomer(Customer customer);   
    public void removeCustomer(Long customerId);   
    public Customer[] listCustomers();   
  
  
}  

  

 

package com.spring.service;   
  
import com.ejb.domain.Customer;   
import com.ejb.service.CustomerService;   
  
/**  
 *  
 * @author meerasubbarao  
 */  
public class CustomerManagerImpl implements CustomerManager {   
  
    CustomerService customerService;   
  
    public void setCustomerService(CustomerService customerService) {   
        this.customerService = customerService;   
    }   
  
    public void removeCustomer(Long customerId) {   
        customerService.remove(customerId);   
    }   
  
    public Customer[] listCustomers() {   
        return customerService.findAllAsArray();   
    }   
  
    public void addCustomer(Customer customer) {   
        customerService.create(customer);   
    }   
}  

 

 

 

6: 注入 EJB 3.0 Session bean 进入我们的 Spring Beans.

 

<?xml version="1.0" encoding="UTF-8"?>  
<beans xmlns="http://www.springframework.org/schema/beans"  
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
       xmlns:context="http://www.springframework.org/schema/context"  
       xmlns:jee="http://www.springframework.org/schema/jee"  
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd   
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd   
       http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd">  
    <jee:jndi-lookup id="customerService" <b>jndi-name="com.ejb.service.CustomerService"</b>>  
    </jee:jndi-lookup>  
    <bean id="manageCustomer"  
        class="com.spring.service.CustomerManagerImpl">  
        <property name="customerService" ref="customerService" />  
    </bean>  
</beans>  

 

 

 

<jee:jndi-lookup id="customerService" jndi-name="com.ejb.service.CustomerService">   
</jee:jndi-lookup>  

 

 

  

<bean id="manageCustomer"  
    class="com.spring.service.CustomerManagerImpl">   
    <property name="customerService" ref="customerService" />   
</bean>  

 

 

 

 

7: 测试

 

package com.spring.client;   
  
import com.ejb.domain.Customer;   
import com.spring.service.CustomerManager;   
import org.springframework.context.ApplicationContext;   
import org.springframework.context.support.ClassPathXmlApplicationContext;   
  
public class SpringAndEJBMain {   
  
    public static void main(String[] args) {   
        ApplicationContext context =   
                new ClassPathXmlApplicationContext("SpringXMLConfig.xml");   
  
        CustomerManager service = (CustomerManager) context.getBean("manageCustomer");   
        Customer customer = new Customer();   
        customer.setFirstName("Meera");   
        customer.setLastName("Subbarao");   
        customer.setMiddleName("B");   
        customer.setEmailId("[email protected]");   
        customer.setCustomerId(new Long(1));   
  
        service.addCustomer(customer);   
        for (Customer cust : service.listCustomers()) {   
            System.out.println(cust.getFirstName());   
            System.out.println(cust.getLastName());   
            System.out.println(cust.getMiddleName());   
            System.out.println(cust.getEmailId());   
  
        }   
        service.removeCustomer(new Long(1));   
  
    }   
}  

 

 

 

 

 

 

 

整个过程结束，使用Spring和EJB 3.0能够同时或者两者的好处。

 

转自：http://www.iteye.com/news/3370