EJB+JPA CRUD实现

本文详细介绍EJB+JPA实现Entity的CRUD基本操作。

目录

• 创建POJO：BlogVo
• 创建Entity：Blog
• 配置persistence.xml
• 定义Remote接口
• 创建SessionBean实现类
• 配置datasource数据源
• 部署EJB工程
• 创建客户端测试类
• 运行测试类

[一]、创建POJO：BlogVo.java

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package com.micmiu.ejb.vo;   import java.io.Serializable;   /** * Blog vo对象 * * @author <a href="http://www.micmiu.com">Michael</a> * @time Create on 2013-9-25 下午3:02:17 * @version 1.0 */ public class BlogVo implements Serializable {   private static final long serialVersionUID = -6384496304647072095L;   private Integer id;   private String title;   private String url;   private String author;   public Integer getId() { return id; }   public String getTitle() { return title; }   public String getUrl() { return url; }   public String getAuthor() { return author; }   public void setId(Integer id) { this.id = id; }   public void setTitle(String title) { this.title = title; }   public void setUrl(String url) { this.url = url; }   public void setAuthor(String author) { this.author = author; }   @Override public String toString() { return "BlogVo [id=" + id + ", title=" + title + ", url=" + url + ", author=" + author + "]"; } }

[二]、创建Entity：Blog.java

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package com.micmiu.ejb.entity;   import java.io.Serializable;   import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.NamedQueries; import javax.persistence.NamedQuery; import javax.persistence.Table;   /** * 实体类blog * * @author <a href="http://www.micmiu.com">Michael</a> * @time Create on 2013-9-24 下午1:57:47 * @version 1.0 */ @Entity @Table(name = "DEMO_T_BLOG") @NamedQueries({ @NamedQuery(name = "queryAll", query = "select t from Blog t ") }) public class Blog implements Serializable {   private static final long serialVersionUID = -1371929956020543775L;   @Id @GeneratedValue @Column(name = "ID") private Integer id;   @Column(name = "TITLE", length = 128) private String title;   @Column(name = "URL", length = 1024) private String url;   @Column(name = "AUTHOR", length = 20) private String author;   public Integer getId() { return id; }   public String getTitle() { return title; }   public String getUrl() { return url; }   public String getAuthor() { return author; }   public void setId(Integer id) { this.id = id; }   public void setTitle(String title) { this.title = title; }   public void setUrl(String url) { this.url = url; }   public void setAuthor(String author) { this.author = author; }   @Override public String toString() { return "Blog [id=" + id + ", title=" + title + ", url=" + url + ", author=" + author + "]"; }   }

[三]、配置persistence.xml

修改配置文件 src: META-INF/persistence.xml 

XHTML

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<?xml version="1.0" encoding="UTF-8"?> <persistence version="2.0" 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_2_0.xsd"> <!-- 为持久化单元取名=micmiuJPA,transaction-type=JTA 利用容器的事务管理 --> <persistence-unit name="micmiuJPA" transaction-type="JTA"> <provider>org.hibernate.ejb.HibernatePersistence</provider>   <jta-data-source>java:/micmiuOracleDS</jta-data-source> <!-- <class>com.micmiu.ejb.entity.Blog</class> --> <!-- 声明是否扫描jar文件中标注了@Enity类.若不扫描,值为true 默认也是true --> <exclude-unlisted-classes>true</exclude-unlisted-classes> <properties> <property name="hibernate.archive.autodetection" value="class,hbm" /> <!--配置Hibernate方言 --> <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect" /> <!--自动输出schema创建DDL语句 --> <property name="hibernate.hbm2ddl.auto" value="update" /> <!-- 输出SQL语句 --> <property name="hibernate.show_sql" value="true" /> <!-- 格式化SQL语句 --> <property name="hibernate.format_sql" value="true" /> </properties> </persistence-unit> </persistence>

ps：<jta-data-source></jta-data-source>配置的值“java:/micmiuOracleDS”需要和JBOSS_HOME/server/default/conf/tandardjbosscmp-jdbc.xml 中配置的<datasource></datasource>一致，详见 下面 第[六]部分 配置datasource数据源

[四]、定义Remote接口

BlogBeanRemote.java

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package com.micmiu.ejb;   import java.util.List;   import javax.ejb.Remote;   import com.micmiu.ejb.vo.BlogVo;   /** * BlogBean remote * * @author <a href="http://www.micmiu.com">Michael</a> * @time Create on 2013-9-25 下午3:05:42 * @version 1.0 */ @Remote public interface BlogBeanRemote {   BlogVo create(BlogVo blog);   BlogVo read(Integer id);   void update(BlogVo blog);   void delete(Integer id);   List<BlogVo> queryAll();   List<BlogVo> queryByAuthor(String author); }

[五]、创建SessionBean实现类

BlogBean.java

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package com.micmiu.ejb;   import java.util.ArrayList; import java.util.List;   import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.Query;   import com.micmiu.ejb.entity.Blog; import com.micmiu.ejb.vo.BlogVo;   /** * Session Bean implementation class BlogBean * * @author <a href="http://www.micmiu.com">Michael</a> * @time Create on 2013-9-25 上午9:20:36 * @version 1.0 */ @Stateless public class BlogBean implements BlogBeanRemote {   @PersistenceContext(unitName = "micmiuJPA") private EntityManager em;   /** * Default constructor. */ public BlogBean() { }   @Override public BlogVo create(BlogVo vo) { Blog po = this.parseVo2Po(vo); em.persist(po); em.flush(); return this.parsePo2Vo(po); }   @Override public BlogVo read(Integer id) { Blog po = em.find(Blog.class, id); return this.parsePo2Vo(po);   }   @Override public void update(BlogVo vo) { Blog po = this.parseVo2Po(vo); em.merge(po); }   @Override public void delete(Integer id) { em.remove(em.getReference(Blog.class, id)); }   @SuppressWarnings("unchecked") @Override public List<BlogVo> queryAll() { List<Blog> list = em.createNamedQuery("queryAll").getResultList(); List<BlogVo> volist = new ArrayList<BlogVo>(); for (Blog po : list) { volist.add(this.parsePo2Vo(po)); } return volist; }   @SuppressWarnings("unchecked") @Override public List<BlogVo> queryByAuthor(String author) { Query query = em.createQuery( "select t from Blog t where t.author =:author").setParameter( "author", author); List<Blog> list = query.getResultList(); List<BlogVo> volist = new ArrayList<BlogVo>(); for (Blog po : list) { volist.add(this.parsePo2Vo(po)); } return volist; }   private Blog parseVo2Po(BlogVo vo) { Blog blog = new Blog(); blog.setAuthor(vo.getAuthor()); blog.setId(vo.getId()); blog.setTitle(vo.getTitle()); blog.setUrl(vo.getUrl()); return blog; }   private BlogVo parsePo2Vo(Blog po) { BlogVo vo = new BlogVo(); vo.setAuthor(po.getAuthor()); vo.setId(po.getId()); vo.setTitle(po.getTitle()); vo.setUrl(po.getUrl()); return vo; } }

ps:

• @PersistenceContext 用来注入 EntityManager
  
• unitName 的值”micmiuJPA” 和配置文件persistence.xml 中定义的名称一致

[六]、配置datasource数据源

数据源配置详见：

EJB部署在JBoss下的datasource配置

[七]、部署EJB工程

导出EJB工程打包，copy 到 JBOSS_HOME/server/default/deploy 默认发布配置下,启动JBOSS即可，能看的类似如下的日志信息：

09:39:43,291 INFO [SessionSpecContainer] Starting jboss.j2ee:jar=EJB-HelloWorld.jar,name=BlogBean,service=EJB3
09:39:43,298 INFO [EJBContainer] STARTED EJB: com.micmiu.ejb.BlogBean ejbName: BlogBean
09:39:43,306 INFO [JndiSessionRegistrarBase] Binding the following Entries in Global JNDI:

BlogBean/remote – EJB3.x Default Remote Business Interface
BlogBean/remote-com.micmiu.ejb.BlogBeanRemote – EJB3.x Remote Business Interface

[八]、创建客户端测试类

把EJB工程中的Remote接口以及引用到的Vo类导出JAR包，copy到客户端工程中，然后创建客户端调用类：BlogBeanClientTest.java

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package com.micmiu.ejb.demo;   import java.util.List; import java.util.Properties;   import javax.naming.InitialContext; import javax.naming.NamingException;   import com.micmiu.ejb.BlogBeanRemote; import com.micmiu.ejb.vo.BlogVo;   /** * 客户端调用测试类 * * @author <a href="http://www.micmiu.com">Michael</a> * @time Create on 2013-9-21 下午2:51:59 * @version 1.0 */ public class BlogBeanClientTest {   /** * @param args */ public static void main(String[] args) { try { Properties props = new Properties(); props.setProperty("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory"); props.setProperty("java.naming.provider.url", "localhost:1099"); props.setProperty("java.naming.factory.url.pkgs", "org.jboss.naming");   System.out.println(">>>> InitialContext "); InitialContext ctx = new InitialContext(props);   System.out.println(">>>> lookup  "); String serviceName = "BlogBean/remote"; BlogBeanRemote remote = (BlogBeanRemote) ctx.lookup(serviceName);   System.out.println(">>>>  操作之前 query michael's Blog"); List<BlogVo> list = remote.queryByAuthor("michael"); System.out.println("query result size = " + list.size()); for (BlogVo blog : list) { System.out.println(blog); }   System.out.println(">>>> create new blog"); BlogVo blog = new BlogVo(); blog.setAuthor("michael"); blog.setTitle("图文演示Eclipse+JBoss创建第一个EJB项目"); blog.setUrl("http://www.micmiu.com/j2ee/ejb/eclipse-jboss-ejb-demo/"); BlogVo createVo = remote.create(blog); System.out.println(createVo);   System.out.println(">>>> read exit blog"); BlogVo readVo = remote.read(1); System.out.println(readVo);   System.out.println(">>>> update blog"); System.out.println("update title " + readVo.getTitle() + " to 大大&&小小 "); readVo.setTitle("大大&&小小"); remote.update(readVo);   System.out.println(">>>>  操作之后 query michael's Blog"); list = remote.queryByAuthor("michael"); System.out.println(">>>> 结果 = " + list.size()); for (BlogVo vo : list) { System.out.println(vo); }   } catch (NamingException e) { e.printStackTrace(); } } }

[九]、运行测试类

运行后日志信息如下：

>>>> InitialContext
>>>> lookup
>>>> 操作之前 query michael’s Blog
query result size = 1
BlogVo [id=1, title=Michael的博客, url=http://www.micmiu.com, author=michael]
>>>> create new blog
BlogVo [id=114, title=图文演示Eclipse+JBoss创建第一个EJB项目, url=http://www.micmiu.com/j2ee/ejb/eclipse-jboss-ejb-demo/, author=michael]
>>>> read exit blog
BlogVo [id=1, title=Michael的博客, url=http://www.micmiu.com, author=michael]
>>>> update blog
update title Michael的博客 to 大大&&小小
>>>> 操作之后 query michael’s Blog
>>>> 结果 = 2
BlogVo [id=1, title=大大&&小小, url=http://www.micmiu.com, author=michael]
BlogVo [id=114, title=图文演示Eclipse+JBoss创建第一个EJB项目, url=http://www.micmiu.com/j2ee/ejb/eclipse-jboss-ejb-demo/, author=michael]