使用EclipseLink JPA插入空结构

k3fezbri 于 2023-02-09 发布在 Eclipse

关注(0)|答案(3)|浏览(139)

我有一个带有SDO_GEOMETRY列的Oracle表，我正尝试使用EclipseLink JPA2 2.6.1进行持久化。我的实体类使用JTS Geometry作为几何对象，我编写了一个AttributeConverter将SDO_GEOMETRY转换为JTS Geometry。这很好用，我可以从数据库读取和写入几何。我遇到的问题是我无法持久化空的JTS Geometry。出现以下错误：
ORA-00932：不一致的数据类型：应为MDSYS. SDO_GEOMETRY，但获得了CHAR
不确定我是做错了什么，还是EclipseLink或Oracle中有bug。
persistence.xml

<?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="mainPersistence">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <class>persistence.v1.dao.jpa2.converters.GeometryConverter</class>

    <class>persistence.v1.dto.AuthorizationDto</class>

    <properties>
        <property name="eclipselink.weaving" value="false"/>
</persistence-unit>

实体类

package persistence.v1.dto;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import persistence.v1.dao.jpa2.converters.GeometryConverter;

import com.vividsolutions.jts.geom.Geometry;

@Entity
@Table(name="AUTHORIZATION")
public class AuthorizationDto {

private String authorizationGuid;
private Geometry authorizationGeometry;

public AuthorizationDto() {
}

@Id
@GeneratedValue(strategy = GenerationType.AUTO, generator = "system-uuid")
@Column(name="AUTHORIZATION_GUID", nullable=false)
public String getAuthorizationGuid() {
    return this.authorizationGuid;
}

public void setAuthorizationGuid(String authorizationGuid) {
    this.authorizationGuid = authorizationGuid;
}

@javax.persistence.Convert(converter=GeometryConverter.class)
@Column(name="AUTHORIZATION_GEOMETRY")
public Geometry getAuthorizationGeometry() {
    return this.authorizationGeometry;
}

public void setAuthorizationGeometry(Geometry authorizationGeometry) {
    this.authorizationGeometry = authorizationGeometry;
}
}

几何转换器类

package persistence.v1.dao.jpa2.converters;

import java.sql.SQLException;
import java.sql.Struct;

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;

import oracle.jdbc.OracleConnection;
import oracle.sql.STRUCT;
import oracle.sql.StructDescriptor;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.io.oracle.OraReader;
import com.vividsolutions.jts.io.oracle.OraWriter;

@Converter(autoApply = true)
public class GeometryConverter implements AttributeConverter<Geometry, Object> {

private static ThreadLocal<OracleConnection> currentConnection = new ThreadLocal<>();

public static void setConnection(OracleConnection connection) {
    currentConnection.set(connection);
}

private Geometry toGeometry(Object geometryData) {
    Geometry result = null;

    OraReader reader = new OraReader();

    try {
        StructDescriptor descriptor = new StructDescriptor(
                "MDSYS.SDO_GEOMETRY", currentConnection.get());
        STRUCT geometryStruct = new STRUCT(descriptor,
                currentConnection.get(), (Object[]) geometryData);

        result = reader.read(geometryStruct);
    } catch (SQLException e) {
        logger.warn("Cound not create geometry from database column", e);
        throw new RuntimeException(e);
    }

    return result;
}

private Struct fromGeometry(Geometry geometry) {
    try {
        return new OraWriter().write(geometry, currentConnection.get());
    } catch (SQLException e) {
        logger.warn("Cound not create database column from geometry "
                + geometry.toText(), e);
        throw new RuntimeException(e);
    }
}

@Override
public Object convertToDatabaseColumn(Geometry geometry) {
    logger.debug("<convertToDatabaseColumn");
    Object result = null;

    if(geometry!=null) {
        result = fromGeometry(geometry);
    }

    logger.debug(">convertToDatabaseColumn "+result);
    return result;
}

@Override
public Geometry convertToEntityAttribute(Object geometryData) {
    logger.debug("<convertToEntityAttribute");
    Geometry result = null;

    if(geometryData!=null) {
        result = toGeometry(geometryData);
    }

    logger.debug(">convertToEntityAttribute "+result);
    return result;
}
}

谢谢

jpa

来源：https://stackoverflow.com/questions/34229944/insert-null-struct-using-eclipselink-jpa

3条答案

按热度按时间

vddsk6oq1#

该异常是由EclipseLink使用VARCHAR作为未知类型的默认值引起的。奇怪的是，AttibuteConverter.convertToEntityAttribute方法接收到SDO_GEOMETRY类型的Object数组而不是Struct，但却期望AttibuteConverter.convertToDatabaseColumn方法返回Struct。这可能是潜在问题的症状。可能有一种方法可以使用注解或其他一些配置来告诉EclipseLink是什么类型，但我无法发现如何做到这一点，所以这是我的变通办法。
我创建了一个EclipseLink SessionEventListener，它使用prelogin方法来识别返回Geometry类型的Entity方法。我使用DatabaseField对象来创建一个新的ObjectRelationalDatabaseField，然后我将sqlType属性设置为Struct，并将sqlTypeName属性设置为“MDSYS.SDO_GEOMETRY”。然后我使用新的ObjectRelationalDatabaseField对象更新Map。EclipseLink代码现在有足够的信息来正确设置语句。setNull（字符串参数名称，int sqlType，字符串类型名称）方法。
在persistence.xml中配置了SessionEventListener，现在空插入成功。
几何初始化器会话事件侦听器类

package persistence.v1.dao.jpa2.listeners;

import java.lang.reflect.Method;
import java.sql.Types;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Vector;

import org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.internal.descriptors.MethodAttributeAccessor;
import org.eclipse.persistence.mappings.DatabaseMapping;
import org.eclipse.persistence.mappings.DirectToFieldMapping;
import org.eclipse.persistence.mappings.structures.ObjectRelationalDatabaseField;
import org.eclipse.persistence.sessions.Session;
import org.eclipse.persistence.sessions.SessionEvent;
import org.eclipse.persistence.sessions.SessionEventListener;

import com.vividsolutions.jts.geom.Geometry;

public class GeometryInitializerSessionEventListener implements SessionEventListener {

// Omitting empty interface methods

@Override
public void preLogin(SessionEvent event) {

    Session s = event.getSession();

    @SuppressWarnings("rawtypes")
    Map<Class, ClassDescriptor> descriptorMap = s.getDescriptors();

    for (@SuppressWarnings("rawtypes") Entry<Class, ClassDescriptor> entry : descriptorMap.entrySet()) {
        Class<?> cls = entry.getKey();
        ClassDescriptor desc = entry.getValue();

        Vector<DatabaseMapping> mappings = desc.getMappings();
        for(DatabaseMapping mapping:mappings) {

            if (mapping.getAttributeAccessor() instanceof MethodAttributeAccessor) {
                MethodAttributeAccessor maa = (MethodAttributeAccessor) mapping.getAttributeAccessor();

                String methodName = maa.getGetMethodName();

                Method method;
                try {
                    method = cls.getMethod(methodName, new Class[]{});
                } catch (NoSuchMethodException e) {
                    throw new RuntimeException(e);
                } catch (SecurityException e) {
                    throw new RuntimeException(e);
                }

                Class<?> returnType = method.getReturnType();

                if(Geometry.class.equals(returnType)) {

                    DirectToFieldMapping directToFieldMapping = (DirectToFieldMapping) mapping;

                    ObjectRelationalDatabaseField objectRelationalDatabaseField = new ObjectRelationalDatabaseField(mapping.getField());
                    objectRelationalDatabaseField.setSqlType(Types.STRUCT);
                    objectRelationalDatabaseField.setSqlTypeName("MDSYS.SDO_GEOMETRY");
                    directToFieldMapping.setField(objectRelationalDatabaseField);
                }
            }
        }
    }
}
}

Persistence.xml

<?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="mainPersistence">
    <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider
    <class>persistence.v1.dao.jpa2.converters.GeometryConverter</class>

    <class>persistence.v1.dto.AuthorizationDto</class>

    <properties>
        <property name="eclipselink.weaving" value="false"/>

        <property name="eclipselink.session-event-listener"  value="persistence.v1.dao.jpa2.listeners.GeometryInitializerSessionEventListener"/>
    </properties>
</persistence-unit>

赞(0）回复(0）举报 2023-02-09

tp5buhyn2#

使用方法标注时，上述答案是正确的。使用字段标注时，请使用GeometryInitializerSessionEventListener的以下实现：

package persistence.dao.jpa2.listeners;

import java.lang.reflect.Field;
import java.sql.Types;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Vector;

import org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.internal.descriptors.InstanceVariableAttributeAccessor;
import org.eclipse.persistence.mappings.DatabaseMapping;
import org.eclipse.persistence.mappings.DirectToFieldMapping;
import org.eclipse.persistence.mappings.structures.ObjectRelationalDatabaseField;
import org.eclipse.persistence.sessions.Session;
import org.eclipse.persistence.sessions.SessionEvent;
import org.eclipse.persistence.sessions.SessionEventListener;

import com.vividsolutions.jts.geom.Geometry;

public class GeometryInitializerSessionEventListener implements SessionEventListener
{
    @Override
    public void preLogin(SessionEvent event)
    {
        Session s = event.getSession();

        @SuppressWarnings("rawtypes")
        Map<Class, ClassDescriptor> descriptorMap = s.getDescriptors();

        for (@SuppressWarnings("rawtypes")
        Entry<Class, ClassDescriptor> entry: descriptorMap.entrySet())
        {
            ClassDescriptor desc = entry.getValue();
            Vector<DatabaseMapping> mappings = desc.getMappings();
            for (DatabaseMapping mapping: mappings)
            {
                if (mapping.getAttributeAccessor() instanceof InstanceVariableAttributeAccessor)
                {
                    InstanceVariableAttributeAccessor ivaa = (InstanceVariableAttributeAccessor)mapping.getAttributeAccessor();

                    try
                    {
                        Field field = getFieldInHierarchy(desc.getJavaClass(), ivaa.getAttributeName());
                        if (Geometry.class.equals(field.getType()))
                        {
                            DirectToFieldMapping directToFieldMapping = (DirectToFieldMapping)mapping;

                            ObjectRelationalDatabaseField objectRelationalDatabaseField = new ObjectRelationalDatabaseField(mapping.getField());
                            objectRelationalDatabaseField.setSqlType(Types.STRUCT);
                            objectRelationalDatabaseField.setSqlTypeName("MDSYS.SDO_GEOMETRY");
                            directToFieldMapping.setField(objectRelationalDatabaseField);
                        }
                    }
                    catch (IllegalArgumentException e)
                    {
                        throw new IllegalStateException(e);
                    }
                }
            }
        }
    }

    private static Field getFieldInHierarchy(Class<?> clazz, String fieldName)
    {
        for (Class<?> c = clazz; c != null; c = c.getSuperclass())
        {
            try
            {
                return c.getDeclaredField(fieldName);
            }
            catch (final NoSuchFieldException e)
            {
                // continue, trying parent
            }
            catch (Exception e)
            {
                throw new IllegalArgumentException("Cannot access field " + clazz.getName() + "." + fieldName, e);
            }
        }

        throw new IllegalArgumentException("Cannot find field " + clazz.getName() + "." + fieldName);
    }
}

赞(0）回复(0）举报 2023-02-09

8qgya5xd3#

这个错误是我忘记注解模型类时发生的，您至少需要使用@Entity和@Id，当然还要在persistance.xml中注册class或your_models.jar

@Entity
class TestModel{
    @Id
    public int id;
    public String name;

    @Override
    public String toString() {
        return "TestModel [id=" + id + ", name=" + name + "]";
    }
}

赞(0）回复(0）举报 2023-02-09

我来回答

使用EclipseLink JPA插入空结构

3条答案

相关问题

热门标签

最新问答