EJB+JPA演示实体类基本操作CRUD的实现

作者: Michael 日期: 2013 年 9 月 25       原文地址：http://www.micmiu.com/j2ee/ejb/ejb-jpa-entity-crud-demo/

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

1package com.micmiu.ejb.vo;

2 

3import java.io.Serializable;

4 

5/**

6 * Blog vo对象

7 *

8 * @author <a href="http://www.micmiu.com">Michael</a>

9 * @time Create on 2013-9-25 下午3:02:17

10 * @version 1.0

11 */

12public class BlogVo implements Serializable {

13 

14    private static final long serialVersionUID = -6384496304647072095L;

15 

16    private Integer id;

17 

18    private String title;

19 

20    private String url;

21 

22    private String author;

23 

24    public Integer getId() {

25        return id;

26    }

27 

28    public String getTitle() {

29        return title;

30    }

31 

32    public String getUrl() {

33        return url;

34    }

35 

36    public String getAuthor() {

37        return author;

38    }

39 

40    public void setId(Integer id) {

41        this.id = id;

42    }

43 

44    public void setTitle(String title) {

45        this.title = title;

46    }

47 

48    public void setUrl(String url) {

49        this.url = url;

50    }

51 

52    public void setAuthor(String author) {

53        this.author = author;

54    }

55 

56    @Override

57    public String toString() {

58        return "BlogVo [id=" + id + ", title=" + title + ", url=" + url

59                + ", author=" + author + "]";

60    }

61}

[二]、创建Entity：Blog.java

1package com.micmiu.ejb.entity;

2 

3import java.io.Serializable;

4 

5import javax.persistence.Column;

6import javax.persistence.Entity;

7import javax.persistence.GeneratedValue;

8import javax.persistence.Id;

9import javax.persistence.NamedQueries;

10import javax.persistence.NamedQuery;

11import javax.persistence.Table;

12 

13/**

14 * 实体类blog

15 *

16 * @author <a href="http://www.micmiu.com">Michael</a>

17 * @time Create on 2013-9-24 下午1:57:47

18 * @version 1.0

19 */

20@Entity

21@Table(name = "DEMO_T_BLOG")

22@NamedQueries({ @NamedQuery(name = "queryAll", query = "select t from Blog t ") })

23public class Blog implements Serializable {

24 

25    private static final long serialVersionUID = -1371929956020543775L;

26 

27    @Id

28    @GeneratedValue

29    @Column(name = "ID")

30    private Integer id;

31 

32    @Column(name = "TITLE", length = 128)

33    private String title;

34 

35    @Column(name = "URL", length = 1024)

36    private String url;

37 

38    @Column(name = "AUTHOR", length = 20)

39    private String author;

40 

41    public Integer getId() {

42        return id;

43    }

44 

45    public String getTitle() {

46        return title;

47    }

48 

49    public String getUrl() {

50        return url;

51    }

52 

53    public String getAuthor() {

54        return author;

55    }

56 

57    public void setId(Integer id) {

58        this.id = id;

59    }

60 

61    public void setTitle(String title) {

62        this.title = title;

63    }

64 

65    public void setUrl(String url) {

66        this.url = url;

67    }

68 

69    public void setAuthor(String author) {

70        this.author = author;

71    }

72 

73    @Override

74    public String toString() {

75        return "Blog [id=" + id + ", title=" + title + ", url=" + url

76                + ", author=" + author + "]";

77    }

78 

79}

[三]、配置persistence.xml

修改配置文件 src: META-INF/persistence.xml 

1<?xml version="1.0" encoding="UTF-8"?>

2<persistence version="2.0"

3    xmlns="http://java.sun.com/xml/ns/persistence"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

4    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence

5             http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">

6    <!-- 为持久化单元取名=micmiuJPA,transaction-type=JTA 利用容器的事务管理 -->

7    <persistence-unit name="micmiuJPA" transaction-type="JTA">

8        <provider>org.hibernate.ejb.HibernatePersistence</provider>

9 

10        <jta-data-source>java:/micmiuOracleDS</jta-data-source>

11        <!-- <class>com.micmiu.ejb.entity.Blog</class> -->

12        <!-- 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 -->

13        <exclude-unlisted-classes>true</exclude-unlisted-classes>

14        <properties>

15            <property name="hibernate.archive.autodetection" value="class,hbm"/>

16            <!--配置Hibernate方言 -->

17            <property name="hibernate.dialect"value="org.hibernate.dialect.Oracle10gDialect" />

18            <!--自动输出schema创建DDL语句 -->

19            <property name="hibernate.hbm2ddl.auto" value="update" />

20            <!-- 输出SQL语句 -->

21            <property name="hibernate.show_sql" value="true" />

22            <!-- 格式化SQL语句 -->

23            <property name="hibernate.format_sql" value="true" />

24        </properties>

25    </persistence-unit>

26</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

1package com.micmiu.ejb;

2 

3import java.util.List;

4 

5import javax.ejb.Remote;

6 

7import com.micmiu.ejb.vo.BlogVo;

8 

9/**

10 * BlogBean remote

11 *

12 * @author <a href="http://www.micmiu.com">Michael</a>

13 * @time Create on 2013-9-25 下午3:05:42

14 * @version 1.0

15 */

16@Remote

17public interface BlogBeanRemote {

18 

19    BlogVo create(BlogVo blog);

20 

21    BlogVo read(Integer id);

22 

23    void update(BlogVo blog);

24 

25    void delete(Integer id);

26 

27    List<BlogVo> queryAll();

28 

29    List<BlogVo> queryByAuthor(String author);

30}

[五]、创建SessionBean实现类

BlogBean.java

1package com.micmiu.ejb;

2 

3import java.util.ArrayList;

4import java.util.List;

5 

6import javax.ejb.Stateless;

7import javax.persistence.EntityManager;

8import javax.persistence.PersistenceContext;

9import javax.persistence.Query;

10 

11import com.micmiu.ejb.entity.Blog;

12import com.micmiu.ejb.vo.BlogVo;

13 

14/**

15 * Session Bean implementation class BlogBean

16 *

17 * @author <a href="http://www.micmiu.com">Michael</a>

18 * @time Create on 2013-9-25 上午9:20:36

19 * @version 1.0

20 */

21@Stateless

22public class BlogBean implements BlogBeanRemote {

23 

24    @PersistenceContext(unitName = "micmiuJPA")

25    private EntityManager em;

26 

27    /**

28     * Default constructor.

29     */

30    public BlogBean() {

31    }

32 

33    @Override

34    public BlogVo create(BlogVo vo) {

35        Blog po = this.parseVo2Po(vo);

36        em.persist(po);

37        em.flush();

38        return this.parsePo2Vo(po);

39    }

40 

41    @Override

42    public BlogVo read(Integer id) {

43        Blog po = em.find(Blog.class, id);

44        return this.parsePo2Vo(po);

45 

46    }

47 

48    @Override

49    public void update(BlogVo vo) {

50        Blog po = this.parseVo2Po(vo);

51        em.merge(po);

52    }

53 

54    @Override

55    public void delete(Integer id) {

56        em.remove(em.getReference(Blog.class, id));

57    }

58 

59    @SuppressWarnings("unchecked")

60    @Override

61    public List<BlogVo> queryAll() {

62        List<Blog> list = em.createNamedQuery("queryAll").getResultList();

63        List<BlogVo> volist = new ArrayList<BlogVo>();

64        for (Blog po : list) {

65            volist.add(this.parsePo2Vo(po));

66        }

67        return volist;

68    }

69 

70    @SuppressWarnings("unchecked")

71    @Override

72    public List<BlogVo> queryByAuthor(String author) {

73        Query query = em.createQuery(

74                "select t from Blog t where t.author =:author").setParameter(

75                "author", author);

76        List<Blog> list = query.getResultList();

77        List<BlogVo> volist = new ArrayList<BlogVo>();

78        for (Blog po : list) {

79            volist.add(this.parsePo2Vo(po));

80        }

81        return volist;

82    }

83 

84    private Blog parseVo2Po(BlogVo vo) {

85        Blog blog = new Blog();

86        blog.setAuthor(vo.getAuthor());

87        blog.setId(vo.getId());

88        blog.setTitle(vo.getTitle());

89        blog.setUrl(vo.getUrl());

90        return blog;

91    }

92 

93    private BlogVo parsePo2Vo(Blog po) {

94        BlogVo vo = new BlogVo();

95        vo.setAuthor(po.getAuthor());

96        vo.setId(po.getId());

97        vo.setTitle(po.getTitle());

98        vo.setUrl(po.getUrl());

99        return vo;

100    }

101}

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：http://www.micmiu.com/j2ee/ejb/ejb-deploy-jboss-ds-config/

[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

1package com.micmiu.ejb.demo;

2 

3import java.util.List;

4import java.util.Properties;

5 

6import javax.naming.InitialContext;

7import javax.naming.NamingException;

8 

9import com.micmiu.ejb.BlogBeanRemote;

10import com.micmiu.ejb.vo.BlogVo;

11 

12/**

13 * 客户端调用测试类

14 *

15 * @author <a href="http://www.micmiu.com">Michael</a>

16 * @time Create on 2013-9-21 下午2:51:59

17 * @version 1.0

18 */

19public class BlogBeanClientTest {

20 

21    /**

22     * @param args

23     */

24    public static void main(String[] args) {

25        try {

26            Properties props = new Properties();

27            props.setProperty("java.naming.factory.initial",

28                    "org.jnp.interfaces.NamingContextFactory");

29            props.setProperty("java.naming.provider.url", "localhost:1099");

30            props.setProperty("java.naming.factory.url.pkgs",

31                    "org.jboss.naming");

32 

33            System.out.println(">>>> InitialContext ");

34            InitialContext ctx = new InitialContext(props);

35 

36            System.out.println(">>>> lookup  ");

37            String serviceName = "BlogBean/remote";

38            BlogBeanRemote remote = (BlogBeanRemote) ctx.lookup(serviceName);

39 

40            System.out.println(">>>>  操作之前 query michael's Blog");

41            List<BlogVo> list = remote.queryByAuthor("michael");

42            System.out.println("query result size = " + list.size());

43            for (BlogVo blog : list) {

44                System.out.println(blog);

45            }

46 

47            System.out.println(">>>> create new blog");

48            BlogVo blog = new BlogVo();

49            blog.setAuthor("michael");

50            blog.setTitle("图文演示Eclipse+JBoss创建第一个EJB项目");

51            blog.setUrl("http://www.micmiu.com/j2ee/ejb/eclipse-jboss-ejb-demo/");

52            BlogVo createVo = remote.create(blog);

53            System.out.println(createVo);

54 

55            System.out.println(">>>> read exit blog");

56            BlogVo readVo = remote.read(1);

57            System.out.println(readVo);

58 

59            System.out.println(">>>> update blog");

60            System.out.println("update title " + readVo.getTitle()

61                    + " to 大大&&小小 ");

62            readVo.setTitle("大大&&小小");

63            remote.update(readVo);

64 

65            System.out.println(">>>>  操作之后 query michael's Blog");

66            list = remote.queryByAuthor("michael");

67            System.out.println(">>>> 结果 = " + list.size());

68            for (BlogVo vo : list) {

69                System.out.println(vo);

70            }

71 

72        } catch (NamingException e) {

73            e.printStackTrace();

74        }

75    }

76}

[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]

本文介绍到此结束@Michael Sun.