这个系列文章我是根据 Rick Hightower 发表在 IBM 网站的文章 《 EJB - CMP/CMR 介绍》 改编而成的,这是一个系列,共有4篇文章。这篇文章综合了那4篇文章,看这篇文章前一定要参考一下,这样理解起来很方便,不过我做了部分修改,原理基本还是不变的。关于 CMP 方面的知识我不说了,我这里只是介绍如何使用 Lomboz 和 JBoss-IDE 在Eclipse 中开发 CMP。
这篇文章主要讲述如何开发一对多的双向联系,这里设计了一个GroupBean,和UserInfoBean建立联系(注意,IBM 网站的文章是和UserBean建立联系,这里我认为和UserInfoBean建立联系更合适)。重点放在如何使用XDoclet建立一对多的双向联系,客户端的调用比较简单。
这篇文章是由 《
Eclipse快速上手EJB -- 2. 设计一个实体Bean》、《
Eclipse快速上手EJB -- 3. 设计一对一的双向关系的CMR(1)》 《
Eclipse快速上手EJB -- 4. 多对多的单向关系的CMR(1) 》延伸而来。所以,必须要有这三篇文章的基础才行。
关于环境配置、使用技巧还是要参考我以前的文章,这里尽量省略。
一、设计实体Bean :GroupBean
1. 建立主体部分:
●
在 CMP_Sample 项目中,右击“src” ->新建 ->Lomboz EJB Creation Wizard :
· 包(K) :javamxj.ejb.cmp
· 名称(M): Group
· EJB Type: 选择 Container Managed Entity EJB
点击下一步。
● Schema Name: GroupSchema
Table Name: GroupTable
● 增加一个 name 栏:
并且使它成为主键。
· Field: name
· Field Type: java.lang.String
· Database Column: 名称
· SQL Type: varchar
● 同样,再增加一个 description 栏:
· Field: description
· Field Type: java.lang.String
· Database Column: 行业说明
· SQL Type: varchar
效果如下,最后点击完成。

注意:如上篇文章一样,将生成代码中的 sql-type="varchar" 改写成 sql-type="varchar(xy)" ,xy是一个合适的VARCHAR 的位数。
2.
完成 ejbCreate 和 ejbPostCreate 方法:

3. 在类标记中加入以下标记:

4. 增加一个Select method ,你可以使用JBoss-IDE得到,这里是代码(后面有完整的源代码):
//######################## Select method ##############################
/**
* Select method
* @ejb.select
* query = "SELECT user.email FROM GroupSchema AS g, IN (g.users) AS user WHERE g.name = ?1"
*
*/
public abstract java.util.Collection ejbSelectUserIDs(String groupName)
throws javax.ejb.FinderException;
/**
* Select method
* @ejb.select
* query = "SELECT user.email FROM GroupSchema AS g, IN (g.users) AS user WHERE g.name = ?1"
*
*/
public abstract java.util.Collection ejbSelectUserIDs(String groupName)
throws javax.ejb.FinderException;
/**
* Home method
* @throws FinderException
* @ejb.home-method view-type = "local"
*/
public java.util.ArrayList ejbHomeGetUserIDs(String groupName)
throws javax.ejb.FinderException {
return (java.util.ArrayList) ejbSelectUserIDs(groupName);
}
5. 将 GroupBean 加入到 cmpEJB 模块中,然后 lomboz ->Generate EJB Classes
6. 重点:建立 GroupBean 与 UserInfoBean 的一对多的双向联系:
● 右击 GroupBean ->J2EE ->Add CMR Relationship :

生成的代码参考下面给出的完整的源代码。
● 切换到
UserInfoBean.java:
右击 UserInfoBean ->J2EE ->Add CMR Relationship :

在 UserInfoBean.java 中生成的代码(需要手工添加
@jboss.relation):
/**
* Getter for CMR Relationship
*
* @ejb.interface-method view-type="local"
* @ejb.relation name = "GroupsHaveUserInfos"
* role-name = "UserInfosInGroup"
* target-multiple = "yes"
* @jboss.relation
* fk-column = "组别"
* related-pk-field = "name"
*/
public abstract javamxj.ejb.cmp.GroupLocal getGroup();
/**
* Setter for CMR Relationship
*
* @ejb.interface-method view-type="local"
*/
public abstract void setGroup(javamxj.ejb.cmp.GroupLocal value);
* Getter for CMR Relationship
*
* @ejb.interface-method view-type="local"
* @ejb.relation name = "GroupsHaveUserInfos"
* role-name = "UserInfosInGroup"
* target-multiple = "yes"
* @jboss.relation
* fk-column = "组别"
* related-pk-field = "name"
*/
public abstract javamxj.ejb.cmp.GroupLocal getGroup();
/**
* Setter for CMR Relationship
*
* @ejb.interface-method view-type="local"
*/
public abstract void setGroup(javamxj.ejb.cmp.GroupLocal value);
Ok,再次 Generate EJB Classes ,如果一切正常,再进行下一步。
● 下面给出了GroupBean.java的完整的源代码:
GroupBean.java
/* * 创建日期 2005-1-26 * * 作者:javamxj(分享java快乐) */ package javamxj.ejb.cmp; /** * * <!-- begin-user-doc --> You can insert your documentation for '<em><b>GroupBean</b></em>'. <!-- end-user-doc --> * <!-- begin-lomboz-definition --> <?xml version="1.0" encoding="UTF-8"?> <lomboz:EJB xmlns:j2ee="http://java.sun.com/xml/ns/j2ee" xmlns:lomboz="http://lomboz.objectlearn.com/xml/lomboz"> <lomboz:entity> <lomboz:entityEjb> <j2ee:display-name>Group</j2ee:display-name> <j2ee:ejb-name>Group</j2ee:ejb-name> <j2ee:ejb-class>javamxj.ejb.cmp.GroupBean</j2ee:ejb-class> <j2ee:persistence-type>Container</j2ee:persistence-type> <j2ee:prim-key-class>java.lang.String</j2ee:prim-key-class> <j2ee:cmp-version>2.x</j2ee:cmp-version> <j2ee:abstract-schema-name>GroupSchema</j2ee:abstract-schema-name> <j2ee:primkey-field>name</j2ee:primkey-field> </lomboz:entityEjb> <lomboz:fieldMappings> <lomboz:fieldName>name</lomboz:fieldName> <lomboz:fieldType>java.lang.String</lomboz:fieldType> <lomboz:columnName>名称</lomboz:columnName> <lomboz:jdbcType>VARCHAR</lomboz:jdbcType> <lomboz:sqlType>varchar</lomboz:sqlType> <lomboz:readOnly>false</lomboz:readOnly> <lomboz:primaryKey>true</lomboz:primaryKey> </lomboz:fieldMappings> <lomboz:fieldMappings> <lomboz:fieldName>description</lomboz:fieldName> <lomboz:fieldType>java.lang.String</lomboz:fieldType> <lomboz:columnName>行业说明</lomboz:columnName> <lomboz:jdbcType>VARCHAR</lomboz:jdbcType> <lomboz:sqlType>varchar</lomboz:sqlType> <lomboz:readOnly>false</lomboz:readOnly> <lomboz:primaryKey>false</lomboz:primaryKey> </lomboz:fieldMappings> <lomboz:tableName>GroupTable</lomboz:tableName> <lomboz:dataSourceName></lomboz:dataSourceName> </lomboz:entity> </lomboz:EJB> <!-- end-lomboz-definition --> * * <!-- begin-xdoclet-definition --> * @ejb.bean name="Group" * jndi-name="Group" * type="CMP" * primkey-field="name" * schema="GroupSchema" * cmp-version="2.x" * view-type = "local" * data-source="" * * @ejb.persistence * table-name="GroupTable" * * * * @ejb.finder * query="SELECT OBJECT(a) FROM GroupSchema as a" * signature="java.util.Collection findAll()" * * @ejb.pk class="java.lang.String" * <!-- end-xdoclet-definition --> * @generated **/ public abstract class GroupBean implements javax.ejb.EntityBean { /** * @ejb.create-method */ public java.lang.String ejbCreate(String name, String description) throws javax.ejb.CreateException { // EJB 2.0 spec says return null for CMP ejbCreate methods. setName(name); setDescription(description); return null; } /** * The container invokes this method immediately after it calls ejbCreate. */ public void ejbPostCreate(String name, String description) throws javax.ejb.CreateException { } /** * CMP Field name * @return the name * @ejb.persistent-field * @ejb.persistence * column-name="名称" * jdbc-type="VARCHAR" * sql-type="varchar(24)" * read-only="false" * @ejb.pk-field * * @ejb.interface-method */ public abstract java.lang.String getName(); /** * @param java.lang.String the new name value * @ejb.interface-method */ public abstract void setName(java.lang.String name); /** * CMP Field description * @return the description * @ejb.persistent-field * @ejb.persistence * column-name="行业说明" * jdbc-type="VARCHAR" * sql-type="varchar(24)" * read-only="false" * * * @ejb.interface-method */ public abstract java.lang.String getDescription(); /** * @param java.lang.String the new description value * @ejb.interface-method */ public abstract void setDescription(java.lang.String description); //######################## Select method ############################## /** * Select method * @ejb.select * query = "SELECT user.email FROM GroupSchema AS g, IN (g.users) AS user WHERE g.name = ?1" * */ public abstract java.util.Collection ejbSelectUserIDs(String groupName) throws javax.ejb.FinderException; /** * Home method * @throws FinderException * @ejb.home-method view-type = "local" */ public java.util.ArrayList ejbHomeGetUserIDs(String groupName) throws javax.ejb.FinderException { return (java.util.ArrayList) ejbSelectUserIDs(groupName); } // ######################## CMR Relationship ############################## /** * Getter for CMR Relationship * * @ejb.interface-method view-type="local" * @ejb.relation name = "GroupsHaveUserInfos" * role-name = "GroupHasUserInfos" * target-multiple = "no" */ public abstract java.util.Collection getUsers(); /** * Setter for CMR Relationship * * @ejb.interface-method view-type="local" */ public abstract void setUsers(java.util.Collection value); }
二、在UserManagementBean中添加业务方法
1. 增加一个 GroupLocalHome 的变量 groupHome,并将它放入 ejbCreate 和 ejbPassivate 方法中。

2. 依次增加以下几个业务方法。
UserManagementBean中有关 GroupBean 的部分(很简单) |
//********************************************************************** // 一对多的双向关系 //********************************************************************** /** * 创建组别 * @throws CreateException * @ejb.interface-method view-type="remote" */ public void createGroup(String groupName, String description) throws CreateException { groupHome.create(groupName, description); } /** * 删除组别 * @throws RemoveException * @throws EJBException * @ejb.interface-method view-type="remote" */ public void removeGroup(String groupName) throws EJBException, RemoveException { groupHome.remove(groupName); } /** * 显示所有组别 * @throws FinderException * @ejb.interface-method view-type="remote" */ public ArrayList getGroups() throws FinderException { ArrayList groupList = new ArrayList(30); Iterator iter = groupHome.findAll().iterator(); while (iter.hasNext()) { GroupLocal group = (GroupLocal) iter.next(); groupList.add(group.getName()); } return groupList; } /** * 将用户添加到组 * @throws FinderException * @ejb.interface-method view-type="remote" */ public void moveUserToGroup(String email, String groupName) throws FinderException { UserInfoLocal user = infoHome.findByPrimaryKey(email); GroupLocal group = groupHome.findByPrimaryKey(groupName); user.setGroup(group); } /** * 验证用户所在组 * @throws FinderException * @ejb.interface-method view-type="remote" */ public boolean inGroup(String email, String groupName) throws FinderException { UserInfoLocal user = infoHome.findByPrimaryKey(email); return user.getGroup().getName().equals(groupName); } /** * 给一组用户增加权限 * @throws FinderException * @ejb.interface-method view-type="remote" */ public void addRoleToUsers(String groupName, String roleName) throws FinderException { GroupLocal group = groupHome.findByPrimaryKey(groupName); RoleLocal role = roleHome.findByPrimaryKey(roleName); Iterator iter = group.getUsers().iterator(); while (iter.hasNext()) { UserInfoLocal user = (UserInfoLocal) iter.next(); user.getUser().getRoles().add(role); } } /** * 通过 ejb.finder 输出某组别的用户 * @throws FinderException * @ejb.interface-method view-type="remote" */ public ArrayList getUserIDsInGroup1(String groupName) throws FinderException { ArrayList userList = new ArrayList(30); GroupLocal group = groupHome.findByPrimaryKey(groupName); Iterator iter = group.getUsers().iterator(); while (iter.hasNext()) { UserInfoLocal element = (UserInfoLocal) iter.next(); userList.add(element.getEmail()); } return userList; } /** * 通过 ejb.select 输出某组别的用户 * Business method * @throws FinderException * @ejb.interface-method view-type = "remote" */ public ArrayList getUserIDsInGroup2(String groupName) throws FinderException { return groupHome.getUserIDs(groupName); } |
3. 好了,保存,Generate EJB Classes,启动MySql, 启动JBoss服务器, Deploy Module 。
如果一切正常,则会在 cmp_sample 库中自动建立一个表:grouptable。
三、创建客户端
1. 右击 src 文件夹 ->新建 ->Lomboz EJB Test Client Wizard:
创建一个 CMPClient4.java 文件 (步骤同前两篇文章一样)。
2. 修改生成的 CMPClient4.java,调用UserManagementBean中的方法。
这里给出了完整的源代码:
CMPClient4.java
/* * 创建日期 2005-1-26 * * 作者:javamxj(分享java快乐) */ package javamxj.ejb.client; import java.rmi.RemoteException; import java.util.ArrayList; import java.util.Hashtable; import java.util.Iterator; import javamxj.ejb.cmp.UserManagement; import javax.ejb.CreateException; import javax.ejb.FinderException; import javax.naming.InitialContext; import javax.naming.NamingException; /** * @author pc * * TODO 要更改此生成的类型注释的模板,请转至 * 窗口 - 首选项 - Java - 代码样式 - 代码模板 */ public class CMPClient4 { private javamxj.ejb.cmp.UserManagementHome getHome() throws NamingException { return (javamxj.ejb.cmp.UserManagementHome) getContext().lookup( javamxj.ejb.cmp.UserManagementHome.JNDI_NAME); } private InitialContext getContext() throws NamingException { Hashtable props = new Hashtable(); props.put(InitialContext.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory"); props.put(InitialContext.PROVIDER_URL, "jnp://127.0.0.1:1099"); // This establishes the security for authorization/authentication // props.put(InitialContext.SECURITY_PRINCIPAL,"username"); // props.put(InitialContext.SECURITY_CREDENTIALS,"password"); InitialContext initialContext = new InitialContext(props); return initialContext; } public void testBean() { try { javamxj.ejb.cmp.UserManagement userMgmt = getHome().create(); createUsers(userMgmt); System.out.println("输出group表中的组名:"); printList(userMgmt.getGroups()); System.out.println("改动前,通过 ejb.finder 输出组别为IT的用户"); printList(userMgmt.getUserIDsInGroup1("IT")); System.out.println("改动:将lisi@bbb.ccc添加到IT组"); userMgmt.moveUserToGroup("lisi@bbb.ccc", "IT"); System.out.println("改动后,通过 ejb.select 输出组别为IT的用户"); printList(userMgmt.getUserIDsInGroup2("IT")); System.out.println("通过用户组给用户增加权限"); userMgmt.addRoleToUsers("IT", "manager"); System.out.println("验证用户所在组"); if (userMgmt.inGroup("javamxj@yahoo.com.cn", "IT")) { System.out.println("javamxj is in the IT group"); } else if (userMgmt.inGroup("javamxj@yahoo.com.cn", "marketing")) { System.out.println("javamxj is now in the marketing group"); } } catch (RemoteException e) { e.printStackTrace(); } catch (CreateException e) { e.printStackTrace(); } catch (NamingException e) { e.printStackTrace(); } catch (FinderException e) { e.printStackTrace(); } } // 创建用户 public static void createUsers(UserManagement userMgmt) throws RemoteException, CreateException { System.out.println("向Group表中添加数据"); userMgmt.createGroup("Marketing", "市场组"); userMgmt.createGroup("Engineering", "工程组"); userMgmt.createGroup("Sales", "销售组"); userMgmt.createGroup("IT", "信息科技组"); } // 输出ArrayList private static void printList(ArrayList list) { Iterator i = list.iterator(); while (i.hasNext()) { Object details = (Object) i.next(); System.out.println(details.toString()); } System.out.println(""); } public static void main(String[] args) { CMPClient4 test = new CMPClient4(); test.testBean(); } }
3. 运行客户端
·控制台输出:

·数据库中相对应的表的改变:



三、创建客户端
1. 右击 src 文件夹 ->新建 ->Lomboz EJB Test Client Wizard:
创建一个 CMPClient4.java 文件 (步骤同前两篇文章一样)。
2. 修改生成的 CMPClient4.java,调用UserManagementBean中的方法。
这里给出了完整的源代码:
CMPClient4.java
/* * 创建日期 2005-1-26 * * 作者:javamxj(分享java快乐) */ package javamxj.ejb.client; import java.rmi.RemoteException; import java.util.ArrayList; import java.util.Hashtable; import java.util.Iterator; import javamxj.ejb.cmp.UserManagement; import javax.ejb.CreateException; import javax.ejb.FinderException; import javax.naming.InitialContext; import javax.naming.NamingException; /** * @author pc * * TODO 要更改此生成的类型注释的模板,请转至 * 窗口 - 首选项 - Java - 代码样式 - 代码模板 */ public class CMPClient4 { private javamxj.ejb.cmp.UserManagementHome getHome() throws NamingException { return (javamxj.ejb.cmp.UserManagementHome) getContext().lookup( javamxj.ejb.cmp.UserManagementHome.JNDI_NAME); } private InitialContext getContext() throws NamingException { Hashtable props = new Hashtable(); props.put(InitialContext.INITIAL_CONTEXT_FACTORY, "org.jnp.interfaces.NamingContextFactory"); props.put(InitialContext.PROVIDER_URL, "jnp://127.0.0.1:1099"); // This establishes the security for authorization/authentication // props.put(InitialContext.SECURITY_PRINCIPAL,"username"); // props.put(InitialContext.SECURITY_CREDENTIALS,"password"); InitialContext initialContext = new InitialContext(props); return initialContext; } public void testBean() { try { javamxj.ejb.cmp.UserManagement userMgmt = getHome().create(); createUsers(userMgmt); System.out.println("输出group表中的组名:"); printList(userMgmt.getGroups()); System.out.println("改动前,通过 ejb.finder 输出组别为IT的用户"); printList(userMgmt.getUserIDsInGroup1("IT")); System.out.println("改动:将lisi@bbb.ccc添加到IT组"); userMgmt.moveUserToGroup("lisi@bbb.ccc", "IT"); System.out.println("改动后,通过 ejb.select 输出组别为IT的用户"); printList(userMgmt.getUserIDsInGroup2("IT")); System.out.println("通过用户组给用户增加权限"); userMgmt.addRoleToUsers("IT", "manager"); System.out.println("验证用户所在组"); if (userMgmt.inGroup("javamxj@yahoo.com.cn", "IT")) { System.out.println("javamxj is in the IT group"); } else if (userMgmt.inGroup("javamxj@yahoo.com.cn", "marketing")) { System.out.println("javamxj is now in the marketing group"); } } catch (RemoteException e) { e.printStackTrace(); } catch (CreateException e) { e.printStackTrace(); } catch (NamingException e) { e.printStackTrace(); } catch (FinderException e) { e.printStackTrace(); } } // 创建用户 public static void createUsers(UserManagement userMgmt) throws RemoteException, CreateException { System.out.println("向Group表中添加数据"); userMgmt.createGroup("Marketing", "市场组"); userMgmt.createGroup("Engineering", "工程组"); userMgmt.createGroup("Sales", "销售组"); userMgmt.createGroup("IT", "信息科技组"); } // 输出ArrayList private static void printList(ArrayList list) { Iterator i = list.iterator(); while (i.hasNext()) { Object details = (Object) i.next(); System.out.println(details.toString()); } System.out.println(""); } public static void main(String[] args) { CMPClient4 test = new CMPClient4(); test.testBean(); } }
3. 运行客户端
·控制台输出:

·数据库中相对应的表的改变:


