将MySQL Geometry映射到EJB实体时出错

Question

I need to add geospatial information, "Points" to be specific, to entries of a MySQL database (v5.5.28). I tried to map the created column "location" to the corresponding property of my java EJB entity ServiceInfo, using the simple code:

@Column(name = "location")
private com.vividsolutions.jts.geom.Point location;

However, this causes the following error:

Exception [EclipseLink-66] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Could not deserialize object from byte array.
Internal Exception: java.io.StreamCorruptedException: invalid stream header: 00000000
Mapping: org.eclipse.persistence.mappings.DirectToFieldMapping[location-->ServiceInfo.location]
Descriptor: RelationalDescriptor(ies.persistence.entity.ServiceInfo --> [DatabaseTable(ServiceInfo)])
at org.eclipse.persistence.exceptions.DescriptorException.notDeserializable(DescriptorException.java:1218)
at org.eclipse.persistence.mappings.converters.SerializedObjectConverter.convertDataValueToObjectValue(SerializedObjectConverter.java:72)
...

I think the problem is the java mysql connector (v5.1.22) doesn't support geospatial information, which surprises me since the database does. Can someone confirm this is the case, or tell me what I might be doing wrong and point me in the right direction?

I'm working in Netbeans 7.2, using JDK 1.7 and a GlassFish Server 3.1.2

Answer 1

Ok, so I finally fixed my problem by making the following changes to my persistence tier:

I switched from a MySQL database to a PostgeSQL database, using the spatial extension PostGIS. The reason for this is that MySQL only partially implements the OpenGIS specifications. Next, I had to change the persistence unit of EclipseLink (JPA 2.0)(Default) to Hibernate (JPA 2.0).

Jars to include in the classpath of both my project and glassfish (which seemed to be unable to find them otherwise. I had to copy them to the root of domain1) are:

• postgresql-9.2-1002.jdbc4.jar
• postgis-jdbc-2.1.0SVN.jar
• Hibernate 4.1.8 (all required jars, ehcache for the optional ones and hibernate-entitymanager-4.1.8.Final.jar for JPA... These are all included in the release bundle)
• hibernate-spatial-4.0-M1.jar (hibernate-spatial-1.1.1.jar and hibernate-spatial-postgis-1.1.1.jar are NOT compatible with Hibernate 4.x!).
• jts-1.8.jar

The resulting persistence.xml file is:

<?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="IES-ejbPU" transaction-type="JTA">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <jta-data-source>jdbc/postgresql_iesdb3</jta-data-source>
    <class>ies.persistence.entity.ServiceInfo</class>
    <exclude-unlisted-classes>true</exclude-unlisted-classes>
    <properties>
      <property name="hibernate.dialect" value="org.hibernate.spatial.dialect.postgis.PostgisDialect"/>
      <property name="hibernate.hbm2ddl.auto" value="update"/>
    </properties>
  </persistence-unit>
</persistence>

The annotations to use for my EJB entitiy are:

@Type(type="org.hibernate.spatial.GeometryType") 
@Column(name = "location", columnDefinition="Geometry")
private com.vividsolutions.jts.geom.Geometry location;

We now have a proper mapping using Hibernate + JPA + PostgeSQL/PostGIS.