由Sessionfactory.getCurrentSession.merge调用时，ConstraintValidator中的@Autowired bean null [英] @Autowired bean null in ConstraintValidator when invoked by Sessionfactory.getCurrentSession.merge
问题描述
如果我明确地调用验证器，它将按预期工作，并且连接到数据库的@Autowired DAO bean被注入如预期的那样。
我以前发现在上述工作之前我需要添加下面的语句。我之前已经广泛使用了@Autowired bean，但是下面的语句对于验证器是由Spring管理的，以及注入到ConstraintValidator中的bean来说是必需的。
< bean id =validator
class =org.springframework.validation.beanvalidation.LocalValidatorFactoryBean/>
但是，如果在SessionFactory.getCurrentSession.merge期间自动调用验证器，则该bean为null。 p>
如果我通过调用javax.Validation.validate直接调用验证器，它会起作用，这让我认为我已经正确设置了Spring配置。
我已经阅读了一些人员无法获得DAO bean @Autowired的帖子，但在我的情况下，它在合并期间被调用时除外。
下面的日志输出显示验证器直接被首先调用，然后被合并操作调用。
07.12.2011 01:58:13 INFO [http-8080-1]（FileTypeAndClassValidator：isValid） - 正在验证...
07.12.2011 01:58:13 INFO [http-8080- 1]（ConstraintValidatorHelper：getPropertyValue） - propertyName = className，returnValue = com.twoh.dto.PurchaseOrder
07.12.2011 01:58:13 INFO [http-8080-1]（ConstraintValidatorHelper：g etPropertyValue） - propertyName = fileTypeId，returnValue = 4
07.12.2011 01:58:13 INFO [http-8080-1]（QueryUtil：createHQLQuery） - 从FileType选择ft.id ft ft.id = fileTypeId和ft.fileClassName =：fileClassName
07.12.2011 01:58:13 INFO [http-8080-1]（BaseDAO：merge） - 实体：com.twoh.dto.PurchaseOrder：1036.
07.12 .2011 01:58:13 INFO [http-8080-1]（FileTypeAndClassValidator：isValid） - 正在验证...
07.12.2011 01:58:13信息[http-8080-1]（ConstraintValidatorHelper：getPropertyValue） - propertyName = className，returnValue = com.twoh.dto.PurchaseOrder
07.12.2011 01:58:13 INFO [http-8080-1]（ConstraintValidatorHelper：getPropertyValue） - propertyName = fileTypeId，returnValue = 4
07.12.2011 01:58:13 INFO [http-8080-1]（FileTypeAndClassValidator：isValid） - java.lang.NullPointerException
以下是ConstraintValidator的代码：
package com.twoh.dto.ConstraintValidation;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
导入org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import com.twoh.dao.IQueryUtil;
@Component
public class FileTypeAndClassValidator implements ConstraintValidator< FileTypeAndClass，Object> {
私有日志记录器= LogFactory.getLog（this.getClass（））;
私人字符串fileClassProperty;
private String fileTypeProperty;
@Autowired
private IQueryUtil queryUtil;
public void initialize（FileTypeAndClass constraintAnnotation）{
this.fileClassProperty = constraintAnnotation.fileClassProperty（）;
this.fileTypeProperty = constraintAnnotation.fileTypeProperty（）;
public boolean isValid（Object object，ConstraintValidatorContext constraintValidatorContext）{
boolean result = true;
logger.info（Validating ...）;
if（object == null）{
result = false;
} else {
try {
String fileClassName = ConstraintValidatorHelper.getPropertyValue（String.class，fileClassProperty，object）;
整数fileTypeId = ConstraintValidatorHelper.getPropertyValue（Integer.class，fileTypeProperty，object）;
result = queryUtil.createHQLQuery（（
select ft.id+
from FileType ft+
where ft.id =：fileTypeId+
和ft.fileClassName =：fileClassName
））
.setParameter（fileTypeId，fileTypeId）
.setParameter（fileClassName，fileClassName）
。 。迭代（）hasNext（）;
} catch（Exception e）{
logger.info（e）;
}
}
返回结果;
}
}
好的在大约18个小时后，我终于遇到了一个网站，他们都描述了它有一个解决方案的问题。食谱：使用Hibernate基于事件的验证与定制的JSR-303验证器和Spring autowired注入
在我当前的项目中，我们想构建一个自定义验证器，
会检查一个在使用Hibernate保存我们的Contact实体的任何实例之前，电子邮件地址已经存在于数据库
中。这
验证器需要注入一个DAO以检查数据库中电子邮件地址的
是否存在。令我们吃惊的是，我们认为
是一件轻而易举的事情，更是一场大风。当我们的bean在
Hibernate的基于事件的验证（在我们的例子中，预插入
事件）的上下文中进行验证时，Spring的注入
根本不起作用。
最后，我的弹簧配置看起来像这样：
...
< constructor-arg ref =validator/>
< constructor-arg ref =hibernateProperties/>
< / bean>
...
< util：properties id =hibernatePropertieslocation =classpath：hibernate.properties/>
< bean id =sessionFactory
class =org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean>
< property name =dataSourceref =myDataSource/>
< property name =packagesToScanvalue =com.twoh/>
< property name =hibernatePropertiesref =hibernateProperties/>
< property name =eventListeners>
< map>
< entry key =pre-insertvalue-ref =beanValidationEventListener/>
< entry key =pre-updatevalue-ref =beanValidationEventListener/>
< / map>
< / property>
< / bean>
I have just implemented Bean Validation with Hibernate.
If I call the validator explicitly it works as expected and my @Autowired DAO bean that connects to the DB is injected as expected.
I had previously discovered that I needed to add the statement below before the above would work. I had made extensive use of @Autowired beans before but the statement below was necessary for the validator to be managed by Spring and the bean injected into the ConstraintValidator.
<bean id="validator"
class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean" />
However when the validator is called automatically during a SessionFactory.getCurrentSession.merge the bean is null.
The fact that it works if I invoke the validator directly with a call to javax.Validation.validate makes me think that I have set up the Spring configuration correctly.
I have read a number for posts where people have been unable to get the DAO bean @Autowired but in my case it is except when called during the merge.
The log output below shows the validator being called directly first and then being called as as a result of a merge operation.
07.12.2011 01:58:13 INFO [http-8080-1] (FileTypeAndClassValidator:isValid) - Validating ...
07.12.2011 01:58:13 INFO [http-8080-1] (ConstraintValidatorHelper:getPropertyValue) - propertyName=className, returnValue=com.twoh.dto.PurchaseOrder
07.12.2011 01:58:13 INFO [http-8080-1] (ConstraintValidatorHelper:getPropertyValue) - propertyName=fileTypeId, returnValue=4
07.12.2011 01:58:13 INFO [http-8080-1] (QueryUtil:createHQLQuery) - select ft.id from FileType ft where ft.id = :fileTypeId and ft.fileClassName = :fileClassName
07.12.2011 01:58:13 INFO [http-8080-1] (BaseDAO:merge) - Entity: com.twoh.dto.PurchaseOrder: 1036.
07.12.2011 01:58:13 INFO [http-8080-1] (FileTypeAndClassValidator:isValid) - Validating ...
07.12.2011 01:58:13 INFO [http-8080-1] (ConstraintValidatorHelper:getPropertyValue) - propertyName=className, returnValue=com.twoh.dto.PurchaseOrder
07.12.2011 01:58:13 INFO [http-8080-1] (ConstraintValidatorHelper:getPropertyValue) - propertyName=fileTypeId, returnValue=4
07.12.2011 01:58:13 INFO [http-8080-1] (FileTypeAndClassValidator:isValid) - java.lang.NullPointerException
Below is the code for the ConstraintValidator:
package com.twoh.dto.ConstraintValidation;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import com.twoh.dao.IQueryUtil;
@Component
public class FileTypeAndClassValidator implements ConstraintValidator<FileTypeAndClass, Object> {
private Log logger = LogFactory.getLog(this.getClass());
private String fileClassProperty;
private String fileTypeProperty;
@Autowired
private IQueryUtil queryUtil;
public void initialize(FileTypeAndClass constraintAnnotation) {
this.fileClassProperty = constraintAnnotation.fileClassProperty();
this.fileTypeProperty = constraintAnnotation.fileTypeProperty();
}
public boolean isValid(Object object, ConstraintValidatorContext constraintValidatorContext) {
boolean result = true;
logger.info("Validating ...");
if (object == null) {
result = false;
} else {
try {
String fileClassName = ConstraintValidatorHelper.getPropertyValue(String.class, fileClassProperty, object);
Integer fileTypeId = ConstraintValidatorHelper.getPropertyValue(Integer.class, fileTypeProperty, object);
result = queryUtil.createHQLQuery((
"select ft.id" +
" from FileType ft" +
" where ft.id = :fileTypeId" +
" and ft.fileClassName = :fileClassName"
))
.setParameter("fileTypeId", fileTypeId)
.setParameter("fileClassName", fileClassName)
.iterate().hasNext();
} catch (Exception e) {
logger.info(e);
}
}
return result;
}
}
Ok after about 18hrs of googling I finally came across a site that both described the problem it has a solution. Recipe: Using Hibernate event-based validation with custom JSR-303 validators and Spring autowired injection
In my current project, we wanted to build a custom validator that would check if an e-mail address already existed in the database before saving any instance of our Contact entity using Hibernate. This validator needed a DAO to be injected in order to check for the existence of the e-mail address in the database. To our surprise, what we thought would be a breeze was more of a gale. Spring’s injection did not work at all when our bean was validated in the context of Hibernate’s event-based validation (in our case, the pre-insert event).
In the end my spring configuration ended up looking like this:
...
<bean id="validator" class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean" />
<bean id="beanValidationEventListener" class="org.hibernate.cfg.beanvalidation.BeanValidationEventListener">
<constructor-arg ref="validator"/>
<constructor-arg ref="hibernateProperties"/>
</bean>
...
<util:properties id="hibernateProperties" location="classpath:hibernate.properties"/>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="myDataSource" />
<property name="packagesToScan" value="com.twoh" />
<property name="hibernateProperties" ref="hibernateProperties"/>
<property name="eventListeners">
<map>
<entry key="pre-insert" value-ref="beanValidationEventListener" />
<entry key="pre-update" value-ref="beanValidationEventListener" />
</map>
</property>
</bean>
这篇关于由Sessionfactory.getCurrentSession.merge调用时，ConstraintValidator中的@Autowired bean null的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
