在頁面中直接顯示EJB集合

littlegai — Wed, 13 Sep 2006 15:33:00 GMT

建立一個Entity Bean，選擇Sqlserver2000中Northwind下Shippers表進行映射。按照向導建立完畢EJB以后，新添一個findAll方法獲取所有對象集合。在Web程序中新建一個EJB Control。最后像下面這樣為JSP添加標簽即可：

< %@?page? language ="java" ?contentType ="text/html;charset=UTF-8" % >
< %@?taglib? uri ="netui-tags-databinding.tld" ?prefix ="netui-data" % >
< %@?taglib? uri ="netui-tags-html.tld" ?prefix ="netui" % >
< %@?taglib? uri ="netui-tags-template.tld" ?prefix ="netui-template" % >
< netui:html >
?? < head >
???? < title > Web?Application?Page title >
?? head >
?? < body >
???? < p >
????????New?Web?Application?Page
???? p >
???? < netui-data:declareControl? controlId ="ShipperControl" ?type ="Controls.ShippersBeanControl" > netui-data:declareControl >
???? < netui-data:callControl? controlId ="ShipperControl" ?method ="findAll" ?resultId ="shippers" />
???? < netui-data:repeater? dataSource ="{pageContext.shippers}" >
???? < netui-data:repeaterHeader >< table >< tr >< th > Shippers th > tr >
???? netui-data:repeaterHeader >
???? < netui-data:repeaterItem >
???? < tr >< td >
???? < netui:label? value ="{container.item.companyName}" ? />
???? < netui:label? value ="{container.item.phone}" ? />
???? tr > td >
???? netui-data:repeaterItem >
???? < netui-data:repeaterFooter > table > netui-data:repeaterFooter >
???? netui-data:repeater >
?? body >
netui:html >

其中：
netui-data:declareControl用來申明一個控件。controlId作為后面的標簽進行調用的標識。type為所建立的EJB Control的類型。
netui-data:callControl用來指明調用控件中的哪一個方法。resultId為返回結果的標識。
定義了這兩個標簽之后，建立netui-data:repeater標簽即可。其中DataSouce中的pageContext是指當前頁，而shippers就是前面聲明的返回值。
container.item.companyName對應了EJB Control中的getCompanyName方法。phone對應了EJB Control中的getPhone方法。

littlegai 2006-09-13 23:33 發表評論

EJB調用EJB

littlegai — Wed, 13 Sep 2006 15:19:00 GMT

1.新建一個CMP的Entity Bean。新的Entity Bean被映射到Sql Server 2000的Northwind Databse的Region表。在按照創建向導完成該Entity Bean的建立以后，可以得到如下所示的代碼：

package ?RegionEJB;

import ?java.util.Collection;
import ?javax.ejb.CreateException;

import ?weblogic.ejb.GenericEntityBean;

/**
?*?@ejbgen:entity
?*???ejb-name?=?"RegionBean"
?*???data-source-name?=?"NorthwindDataSource"
?*???table-name?=?"Region"
?*???prim-key-class?=?"java.lang.Integer"
?*
?*?@ejbgen:jndi-name?remote="ejb.RegionBeanRemoteHome"
?*???local?=?"ejb.RegionBeanHome"
?*
?*?@ejbgen:file-generation?local-class?=?"true"?local-class-name?=?"Region"?local-home?=?"true"?local-home-name?=?"RegionHome"?remote-class="true"?remote-class-name?=?"RegionRemote"?remote-home="true"?remote-home-name?=?"RegionRemoteHome"?value-class?=?"false"?value-class-name?=?"RegionValue"?pk-class?=?"true"
?*?@ejbgen:finder?ejb-ql="SELECT?OBJECT(o)?from?RegionBean?as?o"?generate-on="Local"?signature="Collection?findAll()"
? */

public ? abstract ? class ?RegionBean?
?? extends ?GenericEntityBean
{

?? public ?java.lang.Integer?ejbCreate(Integer?RegionID)
???? throws ?CreateException
?? {
????setRegionID(RegionID);

???? return ? null ;
??}
??
?? public ? void ?ejbPostCreate(Integer?RegionID)?
???? throws ?CreateException
?? {}

?? /**
???*?@ejbgen:cmp-field?column?=?"RegionID"
???*??primkey-field="true"
???*?@ejbgen:local-method
??? */
?? public ? abstract ?Integer?getRegionID();
?? /**
???*?@ejbgen:local-method
??? */
?? public ? abstract ? void ?setRegionID(Integer?val);
??
?? /**
???*?@ejbgen:cmp-field?column?=?"RegionDescription"
???*?@ejbgen:local-method
??? */
?? public ? abstract ?String?getRegionDescription();
?? /**
???*?@ejbgen:local-method
??? */
?? public ? abstract ? void ?setRegionDescription(String?val);
??
}

上面的代碼中已經手動添加了一個叫做findAll的方法，該方法可以得到RegionBean的集合。
2.現在建立一個Session Bean。通過這個Session Bean調用RegionBean的findAll方法，并將之保存到一個數組中。代碼如下：

package ?RegionEJB;

import ?java.io.Serializable;
import ?java.rmi.RemoteException;
import ?java.util.Collection;
import ?java.util.Iterator;
import ?javax.ejb. * ;
import ?weblogic.ejb. * ;
import ?javax.naming.Context;
import ?javax.naming.InitialContext;
import ?javax.ejb.SessionContext;
import ?javax.ejb.SessionBean;
import ?javax.ejb.CreateException;

/**
?*?@ejbgen:session?type="Stateless"
?*???ejb-name?=?"RegionView"
?*
?*?@ejbgen:jndi-name?local="ejb.RegionViewLocalHome"
?*???remote?=?"ejb.RegionViewRemoteHome"
?*
?*?@ejbgen:file-generation?remote-class?=?"true"?remote-class-name?=?"RegionViewRemote"?remote-home?=?"true"?remote-home-name?=?"RegionViewHome"?local-class="true"?local-class-name?=?"RegionViewLocal"?local-home="true"?local-home-name?=?"RegionViewLocalHome"
?*?@ejbgen:ejb-local-ref?type="Entity"?name="ejb/Region"?link="RegionBean"?jndi-name="ejb.RegionBeanHome"?local="Region"?home="RegionHome"?
? */
public ? class ?RegionView
?? extends ?GenericSessionBean
?? implements ?SessionBean
{
????SessionContext?sessionContext;
????Context?context;
????RegionHome?regionHome;
?? public ? void ?ejbCreate()? throws ?CreateException?{
???? // ?Your?code?here
??}
?? public ? void ?setSessionContext(SessionContext?sessionContext)
??{
???? this .sessionContext = sessionContext;
???? try
????{
????????initRegionHome();
????}
???? catch (Exception?ex)
????{
???????? throw ? new ?EJBException(ex.getMessage());
????}
??}
?? private ? void ?initRegionHome()? throws ?Exception
??{
???? final ?String?ENTITY_NAME = " java:comp/env/ejb/Region " ;
???? this .context = new ?InitialContext();
???? if ( null == regionHome)
????{
???????? try
????????{
????????????Object?obj = context.lookup(ENTITY_NAME);
????????????regionHome = (RegionHome)obj;
????????}
???????? catch (Exception?ex)
????????{
???????????? throw ? new ?EJBException(ex.getMessage());
????????}
????}
??}
?? /**
???*?@ejbgen:local-method
??? */
?? public ? void ?addRegion( int ?id,String?desc)? throws ?Exception
??{
???? try
????{
????????Region?region = regionHome.create( new ?Integer(id));
????????region.setRegionDescription(desc);
????}
???? catch (Exception?ex)
????{
???????? throw ? new ?Exception(ex.getMessage());
????????
????}
????
??}
?? /**
???*?@ejbgen:local-method
??? */
?? public ?Object[]?getAllRegionView()? throws ?Exception
??{
???? try
????????{
???????????Collection?collection = regionHome.findAll();
??????????? int ?size = collection.size();
??????????? if (size == 0 )
???????????? throw ? new ?Exception( " Null?Ejb?Object?Found!! " );
???????????RegionInfo[]?regionInfo = new ?RegionInfo[collection.size()];
???????????Iterator?iter = collection.iterator();
??????????? int ?regionIndex = 0 ;
??????????? while (iter.hasNext())
???????????{
???????????????RegionEJB.Region?ejb = (RegionEJB.Region)iter.next();
???????????????regionInfo[regionIndex] = new ?RegionInfo(ejb.getRegionID(),ejb.getRegionDescription());
???????????????regionIndex = regionIndex + 1 ;
??????????????? // regionInfo[regionIndex]=new?RegionInfo(new?Integer(regionIndex),iter.next().getClass().toString());
???????????}
??????????? return ?regionInfo;
????????}
???????? catch (Exception?e)
????????{
??????????? throw ? new ?Exception(e.getMessage());
????????}
????
??}
??? public ? static ? class ?RegionInfo? implements ?Serializable
????{
???????? public ?java.lang.Integer?regionID;
???????? public ?String?regionDescription;
????????
???????? public ?RegionInfo()
????????{
????????}
???????? public ?RegionInfo(java.lang.Integer?regionID,String?regionDescription)
????????{
???????????? this .regionID = regionID;
???????????? this .regionDescription = regionDescription;
????????}
????}
}

在注釋中用@ejbgen來配置Weblogic Workshop所提供的EJBGenerate工具生成EJB。在上面的代碼中，session type是手動添加的。另外為了調用其它的EJB，還要配置ejb-local-ref。因為被發布在同一個服務器中，所以使用本地調用即可。這里提取這段代碼來看一下：

* ?@ejbgen:ejb - local - ref?type = " Entity " ?name = " ejb/Region " ?link = " RegionBean " ?jndi - name = " ejb.RegionBeanHome " ?local = " Region " ?home = " RegionHome " ?

因為被調用的對象類型為Entity Bean，所以在type屬性中選擇Entity。如果被調用對象為Session Bean,則可選擇Session。name為對該引用定義指定的名字。link屬性填入被引用EJB組件的名稱。jndi-name填入被引用EJB的JNDI，local填入本地接口的名稱，home填入home接口的名稱。填寫的時候即可以手動輸入，也可以在右側的property editor中填寫。
這里調用findAll的方法getAllRegionView前面的注釋中需要添加ejbgen:local-method以定義為本地方法，這樣ejbgen才會在生成Bean代碼的時候找到它。
3.在jsp頁面中調用這個Session Bean的方法。

首先添加一個EJB控件來包容該EJB調用。然后再在頁面流中實例化一個EJB控件對象。然后為頁面流添加一個方法getAllRegion，最后配置一下JSP頁面中的netui標簽以展現數據。下面是getAllRegion方法：

public ?Object[]?getAllRegion()
????{
???????? try
????????{
???????????? return ?regionViewCtrl.getAllRegionView();
????????}
???????? catch (Exception?ex)
????????{
???????????? return ? null ;
????????}
????}

下面是JSP頁面的內容：

< %@?page? language ="java" ?contentType ="text/html;charset=UTF-8" % >
< %@?taglib? uri ="netui-tags-databinding.tld" ?prefix ="netui-data" % >
< %@?taglib? uri ="netui-tags-html.tld" ?prefix ="netui" % >
< %@?taglib? uri ="netui-tags-template.tld" ?prefix ="netui-template" % >
< netui:html >
???? < head >
???????? < title >
????????????Web?Application?Page
???????? title >
???? head >
???? < body >
???????? < p >
????????
????????Hi!You?Have?Clicked?Ok?Button!
???????? p >
??????? < netui-data:repeater? dataSource ="{pageFlow.allRegion}" >
???????? < netui-data:repeaterHeader >
???????????? < table? border ="1" >
???????????????? < tr >
???????????????????? < td >< b > ID b > td > ??
???????????????????? < td >< b > Description b > td > ????
???????????????? tr >
???????? netui-data:repeaterHeader >
???????? < netui-data:repeaterItem >
???????????? < tr >
???????????????? < td >
???????????????????? < netui:label? value ="{container.item.regionID}" ? />
???????????????? td >
???????????????? < td >
???????????????????? < netui:label? value ="{container.item.regionDescription}" ? />
???????????????? td >
???????????? tr >
???????? netui-data:repeaterItem >
???????? < netui-data:repeaterFooter >
???????????? table >
???????? netui-data:repeaterFooter > ????
???? netui-data:repeater >
???? body >
netui:html >

littlegai 2006-09-13 23:19 發表評論

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在頁面中直接顯示EJB集合

EJB調用EJB