当Sessionfactory.getCurrentSession.merge调用时,@ Aututired bean在ConstraintValidator中为null

Question

我刚刚用Hibernate实现了Bean Validation.

如果我显式调用验证器它按预期工作,并且按预期注入连接到DB的@Autowired DAO bean.

我以前发现我需要在上面的内容之前添加以下语句.之前我已经广泛使用了@Autowired bean,但下面的语句对于由Spring管理验证器和注入ConstraintValidator的bean是必要的.

<bean id="validator"
class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean" />

但是,当在SessionFactory.getCurrentSession.merge期间自动调用验证器时,bean为null.

如果我通过调用javax.Validation.validate直接调用验证器,它的工作原理使我认为我已正确设置了Spring配置.

我已经读过人们无法获得DAO bean @Autowired的帖子的数字,但在我的情况下,除了在合并期间调用时.

下面的日志输出显示首先直接调用验证器,然后作为合并操作的结果调用.

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

以下是ConstraintValidator的代码:

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;
    }
}

Answer 1

大约18小时的谷歌搜索后,我终于遇到了一个网站,它都描述了它有解决方案的问题.配方:使用基于事件的Hibernate验证与自定义JSR-303验证器和Spring自动注入

在我当前的项目中,我们想要构建一个自定义验证器,在使用Hibernate保存Contact实体的任何实例之前,它将检查数据库中是否已存在电子邮件地址.此验证器需要注入DAO以检查数据库中是否存在电子邮件地址.令我们惊讶的是,我们认为微风更像是一场大风.当我们的bean在Hibernate基于事件的验证(在我们的例子中是插入前事件)的上下文中被验证时,Spring的注入根本不起作用.

最后,我的弹簧配置最终看起来像这样:

...
<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>

Answer 2

从2.5.1开始,您可以使用Spring框架提供的以下方法

SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);

它更清晰,因为您不必在整个应用程序中设置任何侦听器/属性.

你的代码看起来像这样:

public class ValidUniqueUserEmailValidator implements ConstraintValidator<ValidUniqueUserEmail, Object>, Serializable {

    private static final long serialVersionUID = 1L;

    @Autowired
    private UserDAO userDAO;

    @Override
    public void initialize(ValidUniqueUserEmail constraintAnnotation) {
        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
    }

    @Override
    public boolean isValid(Object value, ConstraintValidatorContext context) {
        boolean isValid = true;
        if (value instanceof String) {
            String email = value.toString();
            if (email == null || email.equals("")) {
                isValid = false;
            }else{
                User user = new User();
                user.setEmail(email);
                isValid = (userDAO.countByEmail(user) > 0);
            }
        }
        return isValid;

    }

}

希望它可以帮助你们