我有两个实体/类（客户，订单），分别带有相应的模型bean，jsf页面和支持bean（=控制器bean）。这两个实体的ID都是从类型UUID生成的。一切运行良好。
现在，在“订单”页面中，我试图引入一个<p:selectOneMenu>来选择一个客户（在后台为一个UUID），并将该客户的UUID（->来源）输入到订单中（输入“订单”）。 uuid_Customer'（类型为UUID）（-> target）作为外键。简而言之：源实体和目标实体是不同的。
显示了DropDown，并且我可以选择正确的客户列表。在所有情况下，phaseListener都会显示所选客户的正确UUID。因此，我认为<f:selectItems>标签没有问题。
问题：：提交页面时出现验证错误“验证错误：值无效”。 （目标）字段“ order.uuid_Customer”（类型UUID）在jsf生命周期结束之前一直为空。
我看到了两个可能的错误来源：
1）我误解了两个“值”属性：
<p:selectOneMenu value="#{selectedOrder.uuid_Customer}" ...（=目标）
<f:selectItems value="#{order_Edit_C.customers}" ...（=源）
2）我误解了转换器的功能。
我不确定getAsObject方法应该返回什么。我在UUID中返回类型为UUID的对象order.uuid_Customer。我应该返回对象Customer吗？如果为“是”，则：我应该在哪里提取UUID并将其提交给order.uuid_Customer？
order_Edit.xhtml（摘录）：
<p:inputText id="a_uuid"
value="#{selectedOrder.uuid}"
readonly="true">
</p:inputText>
<p:inputText id="a_name"
value="#{selectedOrder.name}">
</p:inputText>
...
<p:selectOneMenu id="sOM_Order_Edit"
value="#{selectedOrder.uuid_Customer}"
converter="customer_Converter">
<f:selectItem itemLabel="Select One Item"/>
<f:selectItems value="#{order_Edit_C.customers}"
var="customer" itemValue="#{customer}"
itemLabel="#{customer.external_ID} - #{customer.name}" />
<f:validator validatorId="myValidator" />
</p:selectOneMenu>
这些是phaseListener行选择一个客户（显示的UUID是该客户的正确客户）。
16:22:32,956 INFO [stdout] (default task-1) ### 1 ### START PHASE RESTORE_VIEW 1 #####
16:22:32,971 INFO [stdout] (default task-1) ### 1 ### END PHASE RESTORE_VIEW 1 #####
16:22:32,971 INFO [stdout] (default task-1) ### 2 ### START PHASE APPLY_REQUEST_VALUES 2 #####
16:22:32,971 INFO [stdout] (default task-1) - getAsObject: Customer 1 / c582928e-034f-40d5-90ad-ff0901753ca6
16:22:32,971 INFO [stdout] (default task-1) ### 2 ### END PHASE APPLY_REQUEST_VALUES 2 #####
16:22:32,971 INFO [stdout] (default task-1) ### 3 ### START PHASE PROCESS_VALIDATIONS 3 #####
16:22:32,971 INFO [stdout] (default task-1) - getAsObject: Customer 1 / c582928e-034f-40d5-90ad-ff0901753ca6
16:22:32,971 INFO [stdout] (default task-1) MyValidator validate: c582928e-034f-40d5-90ad-ff0901753ca6
16:22:32,987 INFO [stdout] (default task-1) ### 3 ### END PHASE PROCESS_VALIDATIONS 3 #####
16:22:32,987 INFO [stdout] (default task-1) ### 6 ### START PHASE RENDER_RESPONSE 6 #####
16:22:33,003 INFO [stdout] (default task-1) ### 6 ### END PHASE RENDER_RESPONSE 6 #####
这些是提交页面的phaseListener行（请参见空的uuid_Customer：null）：
17:44:41,294 INFO [stdout] (default task-1) ### 1 ### START PHASE RESTORE_VIEW 1 #####
17:44:41,310 INFO [stdout] (default task-1) ### 1 ### END PHASE RESTORE_VIEW 1 #####
17:44:41,310 INFO [stdout] (default task-1) ### 2 ### START PHASE APPLY_REQUEST_VALUES 2 #####
17:44:41,310 INFO [stdout] (default task-1) ### 2 ### END PHASE APPLY_REQUEST_VALUES 2 #####
17:44:41,310 INFO [stdout] (default task-1) ### 3 ### START PHASE PROCESS_VALIDATIONS 3 #####
17:44:41,310 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,310 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,310 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,310 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,310 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,326 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,326 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,326 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,326 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,326 INFO [stdout] (default task-1) - getAsObject: Customer 1 / c582928e-034f-40d5-90ad-ff0901753ca6
17:44:41,326 INFO [stdout] (default task-1) MyValidator validate: c582928e-034f-40d5-90ad-ff0901753ca6
17:44:41,341 INFO [stdout] (default task-1) ### 3 ### END PHASE PROCESS_VALIDATIONS 3 #####
17:44:41,341 INFO [stdout] (default task-1) ### 6 ### START PHASE RENDER_RESPONSE 6 #####
17:44:41,341 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,357 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,357 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,357 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,357 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,357 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,357 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,357 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,357 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,372 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,372 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,372 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,372 INFO [stdout] (default task-1) - Order_P getSelectedOrder: je.de.model.entities.Order.Order@fc402e9
17:44:41,372 INFO [stdout] (default task-1) - uuid: ddbbb88f-2d77-4332-8121-f14d9b873d7f
17:44:41,372 INFO [stdout] (default task-1) - uuid_Contact: null
17:44:41,372 INFO [stdout] (default task-1) - getAsString: NULL / NULL
17:44:41,372 INFO [stdout] (default task-1) - getAsString: Customer 3 / 8d3908bf-700f-470f-ba15-42ebeba662b4
17:44:41,372 INFO [stdout] (default task-1) - getAsString: Customer 2 / 96be56c7-eb04-4e19-b43e-fb6d83373bfd
17:44:41,372 INFO [stdout] (default task-1) - getAsString: Customer 5 / b16a9f77-0644-44d4-b20d-038a0971e422
17:44:41,372 INFO [stdout] (default task-1) - getAsString: Customer 6 / be876edc-af63-435a-9d1b-5f7742400979
17:44:41,372 INFO [stdout] (default task-1) - getAsString: Customer 1 / c582928e-034f-40d5-90ad-ff0901753ca6
17:44:41,372 INFO [stdout] (default task-1) - getAsString: Customer 4 / f41b195a-bfc9-4c6b-872c-ad21b37dab89
17:44:41,388 INFO [stdout] (default task-1) ### 6 ### END PHASE RENDER_RESPONSE 6 #####
和转换器（两种方法均按预期返回值）：
@FacesConverter(value = "customer_Converter")
public class Customer_Converter implements Converter {
@Override
public Object getAsObject(FacesContext facesContext, UIComponent uiComponent, String uuid) {
ValueExpression valueExpression =
facesContext.getApplication().getExpressionFactory()
.createValueExpression(facesContext.getELContext(),
"#{order_Edit_C}", Order_Edit_C.class);
Order_Edit_C customers = (Order_Edit_C)valueExpression.getValue(facesContext.getELContext());
Customer customer = customers.getCustomer(uuid);
System.out.println("- getAsObject: " + customer.getExternal_ID() + " / " + customer.getUuid());
return customer.getUuid();
}
@Override
public String getAsString(FacesContext facesContext, UIComponent uiComponent, Object customer) {
//System.out.println("customer.getClass(): " + customer.getClass());
Customer x = null;
if (customer instanceof Customer) {
Object o = (Object) customer;
Customer c = (Customer) o;
x = c;
}
if (x != null) {
System.out.println("- getAsString: " + x.getExternal_ID() + " / " + x.getUuid());
return x.getUuid().toString();
}
else {
System.out.println("- getAsString: " + "NULL" + " / " + "NULL");
return null;
}
}
}
依赖项：
<dependencies>
<!--
JAVA
-->
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>8.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.persistence</groupId>
<artifactId>javax.persistence-api</artifactId>
<version>2.2</version>
</dependency>
<!--
HIBERNATE
-->
<dependency>
<groupId>org.hibernate.javax.persistence</groupId>
<artifactId>hibernate-jpa-2.1-api</artifactId>
<version>1.0.2.Final</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>5.3.1.Final</version>
<scope>provided</scope>
<exclusions>
<exclusion>
<groupId>dom4j</groupId>
<artifactId>dom4j</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.hibernate.validator</groupId>
<artifactId>hibernate-validator</artifactId>
<version>6.0.10.Final</version>
<exclusions>
<exclusion>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
</exclusion>
</exclusions>
</dependency>
<!--
PRIMEFACES
-->
<dependency>
<groupId>org.primefaces</groupId>
<artifactId>primefaces</artifactId>
<version>6.2</version>
</dependency>
<dependency>
<groupId>org.primefaces.extensions</groupId>
<artifactId>primefaces-extensions</artifactId>
<version>6.2.4</version>
</dependency>
<!--
MYSQL
-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.11</version>
</dependency>
</dependencies>
对于所有以适当方式填写“ order.uuid_Customer”字段（类型UUID）的提示，我表示感谢。