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order.java
package org.jboss.tutorial.entity.bean;
import javax.persistence.cascadetype;
import javax.persistence.entity;
import javax.persistence.fetchtype;
import javax.persistence.generatortype;
import javax.persistence.id;
import javax.persistence.onetomany;
import javax.persistence.table;
import javax.persistence.id;
import javax.persistence.cascadetype;
import javax.persistence.fetchtype;
import java.util.arraylist;
import java.util.collection;
@entity
@table(name = "purchase_order")
//if the table name isnt specified it defaults to the bean name
//of the class. for instance, the lineitem ejb would be mapped to
//the lineitem table
public class order implements java.io.serializable
{
private int id;
private double total;
private collection<lineitem> lineitems;
@id(generate = generatortype.auto)
public int getid()
{
return id;
}
public void setid(int id)
{
this.id = id;
}
public double gettotal()
{
return total;
}
public void settotal(double total)
{
this.total = total;
}
public void addpurchase(string product, int quantity, double price)
{
if (lineitems == null) lineitems = new arraylist<lineitem>();
lineitem item = new lineitem();
item.setorder(this);
item.setproduct(product);
item.setquantity(quantity);
item.setsubtotal(quantity * price);
lineitems.add(item);
total += quantity * price;
}
//cascadetype.all specifies that when an order is created,
//any lineitems held in the lineitems collection will be created
//as well (cascadetype.persist). if the order is delete from
//persistence storage, all related lineitems will be
//deleted (cascadetype.remove). if an order instance is
//reattached to persistence storage, any changes to the
//lineitems collection will be merged with persistence
//storage (cascadetype.merge).
//fetchtype.eager specifies that when the order is loaded
//whether or not to prefetch the relationship as well.
//if you want the lineitems to be loaded on demand, then specify fetchtype.lazy.
// the mappedby attribute specifies that this is a bi-directional
//relationship that is managed by the order property on the lineitem entity bean.
@onetomany(cascade = cascadetype.all, fetch = fetchtype.eager, mappedby="order")
public collection<lineitem> getlineitems()
{
return lineitems;
}
public void setlineitems(collection<lineitem> lineitems)
{
this.lineitems = lineitems;
}
}
加了不少英文注释，希望能看得懂。
@table(name = "purchase_order")
指名数据库（jboss的数据库为hsqldb）中对应得表的名字，默认为class的名字，比如下面的lineitem就没有@table。（order.java , lineitem.java都为o/r映射，值得互相对照）
@id(generate = generatortype.auto)
递增，同数据库里的相同。必须在getter方法上标注。
@onetomany(cascade = cascadetype.all, fetch = fetchtype.eager, mappedby="order")
关系：order和lineitem为1对多的关系。在这里cascadetype.all是指明当建立一个order被实例化后，都应该同时同时建立lineitem。注释里的就是根据两者建立时间的不同，定义了不同的cascadetype。
lineitem.java
package org.jboss.tutorial.entity.bean;
import javax.persistence.entity;
import javax.persistence.generatortype;
import javax.persistence.id;
import javax.persistence.joincolumn;
import javax.persistence.manytoone;
import javax.persistence.entity;
@entity
public class lineitem implements java.io.serializable
{
private int id;
private double subtotal;
private int quantity;
private string product;
private order order;
@id(generate = generatortype.auto)
public int getid()
{
return id;
}
public void setid(int id)
{
this.id = id;
}
public double getsubtotal()
{
return subtotal;
}
public void setsubtotal(double subtotal)
{
this.subtotal = subtotal;
}
public int getquantity()
{
return quantity;
}
public void setquantity(int quantity)
{
this.quantity = quantity;
}
public string getproduct()
{
return product;
}
public void setproduct(string product)
{
this.product = product;
}
//the @joincolumn specifies the foreign key column within the lineitem table.
@manytoone
@joincolumn(name = "order_id")
public order getorder()
{
return order;
}
public void setorder(order order)
{
this.order = order;
}
}
shoppingcart.java
package org.jboss.tutorial.entity.bean;
import javax.ejb.remote;
import javax.ejb.remove;
@remote
public interface shoppingcart
{
void buy(string product, int quantity, double price);
order getorder();
@remove void checkout();
}
shoppingcartbean.java
package org.jboss.tutorial.entity.bean;
import javax.persistence.entitymanager;
import javax.ejb.inject;
import javax.ejb.remove;
import javax.ejb.stateful;
@stateful
public class shoppingcartbean implements shoppingcart
{
@inject
private entitymanager manager; //the entitymanager is used to do querying,
//creating, find by primary key, and removal of entity beans.
private order order;
public void buy(string product, int quantity, double price)
{
if (order == null) order = new order();
order.addpurchase(product, quantity, price);
}
public order getorder()
{
return order;
}
@remove
public void checkout()
{
manager.persist(order);
}
}
entitymanager的作用可大了，可以用于查询，创建，删除实体bean,这里插入个entitymanager,主要是在最后用户离开时，在数据库里保存数据，相当于保存个object。运行完client.java后就可以在hsqldb上看到有purchase_order 和 lineitem 的两张表。hypersonicdatabase ，找到startdatabasemanager然后下面有个invoke,点击就可以访问hsqldb了。
client.java
package org.jboss.tutorial.entity.client;
import org.jboss.tutorial.entity.bean.lineitem;
import org.jboss.tutorial.entity.bean.order;
import org.jboss.tutorial.entity.bean.shoppingcart;
import javax.naming.initialcontext;
public class client
{
public static void main(string[] args) throws exception
{
initialcontext ctx = new initialcontext();
shoppingcart cart = (shoppingcart) ctx.lookup(shoppingcart.class.getname());
system.out.println("buying 2 memory sticks");
cart.buy("memory stick", 2, 500.00);
system.out.println("buying a laptop");
cart.buy("laptop", 1, 2000.00);
system.out.println("print cart:");
order order = cart.getorder();
system.out.println("total: $" + order.gettotal());
for (lineitem item : order.getlineitems())
{
system.out.println(item.getquantity() + " " + item.getproduct() + " " + item.getsubtotal());
}
system.out.println("checkout");
cart.checkout();
}
}
这里附上log4j.properties 在jboss-ejb-3.0_preview_5.zip 里面没有这个老是显示缺少appender。有了这个将在该目录下生成个record.log日志文件。
log4j.properties
log4j.appender.r=org.apache.log4j.rollingfileappender
log4j.appender.r.file=record.log
log4j.appender.r.layout=org.apache.log4j.patternlayout
log4j.appender.r.layout.conversionpattern=%p %d{hh:mm:ss} %t %c{1} -%m%n
log4j.appender.r.maxbackupindex=1
log4j.appender.r.maxfilesize=100kb
log4j.appender.stdout.layout=org.apache.log4j.patternlayout
log4j.appender.stdout.layout.conversionpattern=%5p [%t] (%f:%l) -%m%n
log4j.appender.stdout=org.apache.log4j.consoleappender
log4j.rootlogger=stdout,r
运行：参考installing.html
windows下
打开命令提示符cmd，到 jboss_home/bin
run.bat –c all
用ant
先build后run 就行了。
