Question

我是一个Neo4j / Spring数据新手，如果这是显而易见的事情，我很抱歉，但我看到这里和那里，并不能弄清楚它是否是一个错误或功能。我正在使用SDN 3.1.0和Neo4j 2.0.4，现在在内存中运行（用于测试）。

我有一个超级简单的POJO，我尝试使用SDN保存到Neo4j中。它看起来像这样：

@NodeEntity
public class Weekday {

@GraphId
private Long id;

@Indexed(unique = true)
public DayOfWeek weekdayCode;
}

当我使其非唯一索引或根本没有索引时，一切都很美妙。当我将它设为String时，它可以使用唯一约束。（好吧，有点，我知道它不会抛出异常而是默默地更新现有的 - 这不是完美的但我发现JIRA问题与此相关）。不幸的是，当我尝试将其保存为具有唯一约束的枚举时，我得到一个例外：

org.springframework.dao.InvalidDataAccessResourceUsageException: Error executing statement MERGE (n:`Weekday` {`weekdayCode`: {value}}) ON CREATE SET n={props}  return n; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: Error executing statement MERGE (n:`Weekday` {`weekdayCode`: {value}}) ON CREATE SET n={props}  return n; nested exception is java.lang.IllegalArgumentException: [MONDAY:java.time.DayOfWeek] is not a supported property value
at org.springframework.data.neo4j.support.query.CypherQueryEngineImpl.query(CypherQueryEngineImpl.java:61)
at org.springframework.data.neo4j.support.schema.SchemaIndexProvider.merge(SchemaIndexProvider.java:114)
at [...]
Caused by: org.springframework.dao.InvalidDataAccessResourceUsageException: Error executing statement MERGE (n:`Weekday` {`weekdayCode`: {value}}) ON CREATE SET n={props}  return n; nested exception is java.lang.IllegalArgumentException: [MONDAY:java.time.DayOfWeek] is not a supported property value
at org.springframework.data.neo4j.support.query.CypherQueryEngineImpl.parseAndExecuteQuery(CypherQueryEngineImpl.java:72)
at org.springframework.data.neo4j.support.query.CypherQueryEngineImpl.query(CypherQueryEngineImpl.java:58)
... 63 more
Caused by: java.lang.IllegalArgumentException: [MONDAY:java.time.DayOfWeek] is not a supported property value
at org.neo4j.kernel.api.properties.PropertyConversion.convertProperty(PropertyConversion.java:107)
at org.neo4j.kernel.api.properties.Property.property(Property.java:51)
at [...]

据我所知，这是因为将唯一字段放入地图“props”中，并且地图的内容不会自动转换，因此它会向Neo4j发送枚举，这显然不会等。

这是预期还是我应该提出SDN的错误？
如果这是预期的行为，除了将字段设为字符串外，我还有其他选择吗？

Answer 1

我不确定它是不是真正的错误，但是我使用自己的Enum类时遇到了类似的问题。

所以，你可以尝试这样的事情：

创建转换器
在neo4j

首先创建您的转换器，如：

@Component
public class StringToDayOfWeekConverter implements Converter<String, DayOfWeek> {

    @Override
    public DayOfWeek convert(String source) {
        return DayOfWeek.valueOf(source);
    }
}

@Component
public class DayOfWeekToStringConverter implements Converter<DayOfWeek, String> {

    @Override
    public String convert(DayOfWeek source) {
        return source.name();
    }

}

然后你注册转换器，所以neo4j可以使用它们：

@Configuration
@EnableNeo4jRepositories("my.repository.package")
@EnableTransactionManagement
public class MyNeo4jConfiguration extends Neo4jConfiguration {

    @Autowired
    private StringToDayOfWeekConverter stringToDayOfWeekConverter;

    @Autowired
    private DayOfWeekToStringConverter dayOfWeekToStringConverter;


    @Override
    protected ConversionService neo4jConversionService() throws Exception {
        ConverterRegistry converterRegistry = (ConverterRegistry) super.neo4jConversionService();
        converterRegistry.addConverter(stringToDayOfWeekConverter);
        converterRegistry.addConverter(dayOfWeekToStringConverter);
        return (ConversionService) converterRegistry;
    }

}

Answer 2

创建一个转换器扩展EnumStringConverter，如下所示：

package com.noopu.pyramid.domain.model.converter;

import com..pyramid.common.UserType;
import org.neo4j.ogm.typeconversion.EnumStringConverter;
public class UserTypeStringConverter extends EnumStringConverter {

    public UserTypeStringConverter ( ) {
        super ( UserType.class );
    }
}

并使用@Converter注释，例如：

package com.noopu.pyramid.domain.model;

import com.noopu.pyramid.common.UserType;
import com.noopu.pyramid.domain.model.converter.UserTypeStringConverter;
import lombok.Data;
import org.neo4j.ogm.annotation.GraphId;
import org.neo4j.ogm.annotation.Index;
import org.neo4j.ogm.annotation.NodeEntity;
import org.neo4j.ogm.annotation.typeconversion.Convert;

import java.io.Serializable;


@NodeEntity
@Data
public class User  implements Serializable {

    private static final long serialVersionUID = 8979348201709416439L;

    @GraphId
    private Long graphId;

    @Index
    protected Long id;

    @Index(unique = true)
    private Long uid;

    @Index(unique = true)
    private String phone;

    @Index
    @Convert(UserTypeStringConverter.class)
    private UserType type;

}

枚举转换为String不在@Indexed唯一字段上工作

2 个答案: