解决JPA工程在Glassfish下部署失败问题

    关键字：org.xml.sax.SAXParseException: cvc-complex-type.2.4.d: Invalid content was found starting with element 'class'. No
child element is expected at this point.
  
    这段时间做的一个项目，部署环境是GlassFish，但始终部署失败，但在tomcat下一切正常。错误如下：

Caused by: org.xml.sax.SAXParseException: cvc-complex-type.2.4.d: Invalid content was found starting with element 'class'. No child element is 
expected at this point.
	at com.sun.enterprise.deployment.io.DeploymentDescriptorFile.read(DeploymentDescriptorFile.java:304)
	at com.sun.enterprise.deployment.archivist.ExtensionsArchivist.open(ExtensionsArchivist.java:115)
	at com.sun.enterprise.deployment.archivist.PersistenceArchivist.readPersistenceDeploymentDescriptor(PersistenceArchivist.java:125)
	at com.sun.enterprise.deployment.archivist.WarPersistenceArchivist.open(WarPersistenceArchivist.java:88)
	at com.sun.enterprise.deployment.archivist.Archivist.readRestDeploymentDescriptors(Archivist.java:383)
	at com.sun.enterprise.deployment.archivist.Archivist.readDeploymentDescriptors(Archivist.java:373)
	at com.sun.enterprise.deployment.archivist.Archivist.open(Archivist.java:238)
	at com.sun.enterprise.deployment.archivist.Archivist.open(Archivist.java:247)
	at com.sun.enterprise.deployment.archivist.Archivist.open(Archivist.java:208)
	at com.sun.enterprise.deployment.archivist.ApplicationFactory.openArchive(ApplicationFactory.java:161)
	at org.glassfish.javaee.core.deployment.DolProvider.load(DolProvider.java:162)
	... 31 more

引起的原因是在persistence.xml文件中：

<?xml version="1.0" encoding="UTF-8"?> 
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
	<persistence-unit name="MyProject" transaction-type="RESOURCE_LOCAL">
		<properties>
			<property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider"/>
			<property name="hibernate.cache.use_query_cache" value="true"/>
			<property name="hibernate.generate_statistics" value="true"/>
			<property name="hibernate.cache.use_second_level_cache" value="true"/>
			<property name="hibernate.cache.provider_configuration_file_resource_path" value="ehcache/ehcache-hibernate-local.xml"/>
			<property name="hibernate.jdbc.fetch_size" value="50"/>
			<property name="hibernate.jdbc.batch_size" value="30"/>
		</properties>

                <!--报错说此行无效-->
		<class>org.workin.trace.domain.BehaviorPerformance</class> 
	</persistence-unit>
</persistence>

    这样配置的原因是项目中有部分实体类是放在Jar包中的，需要显示配置才能扫描得到。在网上找了N久，始终未能解决。 昨天将
eclipse工作区下的.metadata文件夹删掉，重新建立一个工作区，发现该项目persistence.xml文件中<class>com.xxx</class>这一行报错。起初还以为是XSD引用错误，但是比对了一下，这个和官网上的一模一样。
    在多次失败之后，我将<class>...</class> 放到<properties>...</properties>之前定义，发现eclipse验证居然通过了。再将其发布到GlassFish下，问题不再出现。

更改之后的代码如下：

<?xml version="1.0" encoding="UTF-8"?> 
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
	<persistence-unit name="MyProject" transaction-type="RESOURCE_LOCAL">
            <class>org.workin.trace.domain.BehaviorPerformance</class>		
            <properties>
			<property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider"/>
			<property name="hibernate.cache.use_query_cache" value="true"/>
			<property name="hibernate.generate_statistics" value="true"/>
			<property name="hibernate.cache.use_second_level_cache" value="true"/>
			<property name="hibernate.cache.provider_configuration_file_resource_path" value="ehcache/ehcache-hibernate-local.xml"/>
			<property name="hibernate.jdbc.fetch_size" value="50"/>
			<property name="hibernate.jdbc.batch_size" value="30"/>
		</properties>
	</persistence-unit>
</persistence>

    错误发生原因： W3C XML架构xsd规范中<xsd:sequence>要求组中的元素以指定的顺序出现在包含元素中,Glassfish在部署时会根据xsd对文件进行验证。而Tomcat中未出现类似问题，原因可能是GlassFish的验证比Tomcat更加严谨。
  
    总结： 在用Eclipse开发时，validation这一项尽量不要禁用，虽然开启它会使得Eclipse速度很慢，但是却能及时提醒你错误信息。