标签：style blog http io ar color os 使用 sp
具体选型为EJB+springMVC+spring+JPA稍微技术选型和大家分享
实体是轻量级持久域对象，通常表示在关系数据库中的表。一个POJO成为一个实体bean的主要要求是该类必须与javax.persistence.Entity注解注释。表示一个主键属性或字段，使用javax.persistence.Id注解，告诉EJB容器这是EJB的实体bean
<span style="font-size:18px;"><span style="font-size:18px;"><span style="font-size:18px;">package Jc.entity;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import org.hibernate.annotations.GenericGenerator;
@Entity
@Table(name="lisheheceshi_Student")
public class Student implements Serializable {
private static final long serialVersionUID = -4969613879943565834L;
@Id
@GeneratedValue(generator="hibernateuuidgenerator")
@GenericGenerator(name="hibernateuuidgenerator",strategy="uuid")
@Column(name="studentId",length=32)
private String studentId;
@Column(name="studentCode",length=32)
private String studentCode;
public String getStudentCode() {
return studentCode;
}
public void setStudentCode(String studentCode) {
this.studentCode = studentCode;
}
public String getStudentId() {
return studentId;
}
public void setStudentId(String studentId) {
this.studentId = studentId;
}
public static long getSerialversionuid() {
return serialVersionUID;
}
}
</span></span></span><span style="font-size:18px;"><span style="font-size:18px;"><span style="font-size:18px;">package mgr.student.service.impl;
import javax.ejb.EJB;
import javax.ejb.Remote;
import javax.ejb.Stateless;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;
import javax.ejb.TransactionManagement;
import javax.ejb.TransactionManagementType;
import jc.eao.IStudentEao;
import Base.Service.impl.BaseServiceImpl;
import Base.eao.IBaseEao;
import Jc.entity.Student;
import Jc.mgr.student.service.IStudentBean;
@Stateless
@Remote(IStudentBean.class)
@TransactionManagement(TransactionManagementType.CONTAINER)
@TransactionAttribute(TransactionAttributeType.REQUIRED)
public class StudentBeanimpl extends BaseServiceImpl<Student> implements IStudentBean {
@EJB(beanName="BaseEao")
private IBaseEao BaseEao;
public boolean test(Student student) {
System.out.print("李社河是好人调到ejb了");
BaseEao.save(student);
System.out.print("李社河是好人调到Eao了");
return false;
}
// @Override
// public IBaseEao<Student> getEao() {
// return this.studentEao;
// }
//
// public void save()
// @EJB(beanName="studentEao")
// private IStudentEao studentEao;
// public boolean test(Student student) {
//
// System.out.print("李社河是好人调到ejb了");
// studentEao.save(student);
// System.out.print("李社河是好人调到Eao了");
// return false;
// }
// public IStudentEao getStudentEao() {
// return studentEao;
// }
// public void setStudentEao(IStudentEao studentEao) {
// this.studentEao = studentEao;
// }
//// @Override
//// public IBaseEao<Student> getEao() {
//// return this.studentEao;
//// }
////
//// public void save()
}
</span></span></span><span style="font-size:18px;"><span style="font-size:18px;">package jc.action;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import Jc.entity.Student;
import Jc.mgr.student.service.IStudentBean;
@Controller
public class TestController {
private IStudentBean studentbean;
private Student student;
@RequestMapping("/add")
public String add(HttpServletRequest request, HttpServletResponse response) {
System.out.println("ssss");
Student student =new Student();
student.setStudentId("001");
student.setStudentCode("lishehe");
studentbean.test(student);
return "/list.jsp";
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
public IStudentBean getStudentbean() {
return studentbean;
}
public void setStudentbean(IStudentBean studentbean) {
this.studentbean = studentbean;
}
}
</span></span>
配置数据库链接xml
<span style="font-size:18px;"><span style="font-size:18px;"><?xml version="1.0" encoding="UTF-8"?>
<persistence 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" version="1.0">
<persistence-unit name="Jc-entity" transaction-type="JTA">
<!-- <provider>net.bull.javamelody.JpaPersistence</provider> -->
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<!-- <jta-data-source>java:/MySqlDS</jta-data-source> -->
<!-- <jta-data-source>java:/JcOracleDS</jta-data-source> -->
<jta-data-source>java:jboss/datasources/JcOracleDS</jta-data-source>
<class>Jc.entity.Student</class>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
<!-- <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/> -->
<property name="hibernate.hbm2ddl.auto" value="update" />
<property name="hibernate.show_sql" value="true" />
<!-- 指定二级缓存产品的提供商 -->
<!-- <property name="hibernate.cache.provider_class" -->
<!-- value="net.sf.ehcache.hibernate.SingletonEhCacheProvider"/> -->
<!-- <property name="hibernate.cache.region.factory_class" -->
<!-- value="org.hibernate.cache.ehcache.EhCacheRegionFactory"/> -->
<!-- 开启二级缓存 -->
<!-- <property name="hibernate.cache.use_second_level_cache" value="true"/> -->
<!-- 开启查询缓存 -->
<!-- <property name="hibernate.cache.use_query_cache" value="true"/> -->
<!-- 指定缓存配置文件位置 -->
<!-- <property name="hibernate.cache.provider_configuration_file_resource_path" -->
<!-- value="/ehcache.xml"/> -->
</properties>
</persistence-unit>
</persistence>
</span></span>
Spring的applicationContext-common配置
<span style="font-size:18px;"><span style="font-size:18px;"><context:component-scan base-package="jc.action"/></span></span>
，通过jndi查找到EJB的Bean，之后通过spring容器把StudentBean注入到Controller.调用
<span style="font-size:18px;"><span style="font-size:18px;"><?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jee="http://www.springframework.org/schema/jee" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd"> <!-- <bean id="test" class="Jc.mgr.student.service.impl.StudentBeanimpl"> --> <!-- </bean> --> <jee:local-slsb id="StudentBean" jndi-name="global/lishehe_core/StudentBeanimpl!Jc.mgr.student.service.IStudentBean" business-interface="Jc.mgr.student.service.IStudentBean" /> <bean name="/testController/**" class="jc.action.TestController"> <property name="studentbean" ref="StudentBean"></property> </bean> <!-- 注解探测器 --> <!-- <context:component-scan base-package="com.sfpay"/> --> <!-- annotation默认的方法映射适配器 --> <!-- <bean id="handlerMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" /> --> <!----> <!-- <bean id="handlerAdapter" class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" /> --> </beans> </span></span>
<span style="font-size:18px;"><?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:applicationContext-*.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app></span>运行后打出EJB的信息
<span style="font-size:18px;">0:36:42,255 INFO [org.jboss.as.ejb3.deployment.processors.EjbJndiBindingsDeploymentUnitProcessor] (MSC service thread 1-8) JNDI bindings for session bean named StudentBeanimpl in deployment unit deployment "lishehe_core.jar" are as follows: java:global/lishehe_core/StudentBeanimpl!Jc.mgr.student.service.IStudentBean java:app/lishehe_core/StudentBeanimpl!Jc.mgr.student.service.IStudentBean java:module/StudentBeanimpl!Jc.mgr.student.service.IStudentBean java:jboss/exported/lishehe_core/StudentBeanimpl!Jc.mgr.student.service.IStudentBean java:global/lishehe_core/StudentBeanimpl java:app/lishehe_core/StudentBeanimpl java:module/StudentBeanimpl 20:36:42,257 INFO [org.jboss.as.ejb3.deployment.processors.EjbJndiBindingsDeploymentUnitProcessor] (MSC service thread 1-8) JNDI bindings for session bean named BaseEao in deployment unit deployment "lishehe_core.jar" are as follows: java:global/lishehe_core/BaseEao!Base.eao.IBaseEao java:app/lishehe_core/BaseEao!Base.eao.IBaseEao java:module/BaseEao!Base.eao.IBaseEao java:jboss/exported/lishehe_core/BaseEao!Base.eao.IBaseEao java:global/lishehe_core/BaseEao java:app/lishehe_core/BaseEao java:module/BaseEao 20:36:42,257 INFO [org.jboss.as.ejb3.deployment.processors.EjbJndiBindingsDeploymentUnitProcessor] (MSC service thread 1-8) JNDI bindings for session bean named studentEao in deployment unit deployment "lishehe_core.jar" are as follows: java:global/lishehe_core/studentEao!jc.eao.IStudentEao java:app/lishehe_core/studentEao!jc.eao.IStudentEao java:module/studentEao!jc.eao.IStudentEao java:jboss/exported/lishehe_core/studentEao!jc.eao.IStudentEao java:global/lishehe_core/studentEao java:app/lishehe_core/studentEao java:module/studentEao</span>
页面程序访问到的结果提示：
<span style="font-size:18px;">20:37:14,027 INFO [stdout] (http-localhost/127.0.0.1:8080-1) 李社河是好人调到ejb了BaseEaoImpl中的save方法开始调用</span>
总结EJB的优点
假定一个JavaBeans为A，那么一般使用这个JavaBeans命令如下：
A a = new A();
但是，在高访问量的环境中，new A()其实是很费时消耗系统性能的，因此，能不能在软件系统启动时候就预先建立一些对象，这样，系统运行时，从这些已经生成的对象池中借用一个，这样，就无需在使用时进行New，节约了开销，提高了性能，因此，真正成熟性能解决方案都是需要对象池等支持。
在一个纯Web结构的系统（也就是只能运行在Tomat环境中），例如Struts + Hibernate等这样的系统，除非自己动手做，一般是没有对象池技术支持的，因此他们的性能只能算是Demo演示版本的性能，根本无法承受大容量并发访问，也无法称为一个成熟的系统，所以，我们研究成熟的开源Web系统，如Jive、OFBize，LifeRay等，他们都在Web层拥有自己的对象池和缓存池。
对象池和缓存机制是J2EE必须的吗？当然，是所有成熟系统必须的，Windows系统如果去掉缓存将会变得怎样？
自己动手开发对象池和缓存机制并不是一件简单的事情，需要对多线程以及同步锁等底层原理有深层次的把握，这其实也是一门非常深入的Java研究分支，所以，你可以抛开你的客户焦急的催促，精心研究开发自己的对象池和缓存池。
但是，EJB容器（如JBoss）已经提供了对象池和缓存机制，所以，没有事务机制的无状态Session Bean的性能肯定要强于普通JavaBeans。EJB容器不但在单机中提供了对象池和缓存，而且可以跨服务器实现动态负载平衡，这些都无需开发者自己开发任何软件代码，结构如下：
每一个jar包代表一个EJB组件，一个系统可以由多个可重用的EJB组件构成，例如：树形结构EJB组件；自增序号EJB组件；用户资料EJB组件等，这样的EJB组件可以象积木一样搭配在大部分应用系统中，提高了系统的开发效率，保证了开发质量。
EJB提供的事务机制非常周全，但事务机制带来的缺点是性能的降低，因此，有些人认为EJB很重，因为在实际应用中，有的用户系统可能不需要事务机制，只是需要EJB提供的性能优化机制，这样，如果使用EJB，就象叫一个人来背东西，他除了背着我要的东西外，还背着我不要的东西。
除非你是一个完美主义，在一般企业应用或数据库系统应用中，EJB不会对你构成很重的包袱。
集成JPA+springmvc+spring+EJB中的Java EE应用
标签：style blog http io ar color os 使用 sp
原文地址：http://blog.csdn.net/lishehe/article/details/41622175
