spring-data-neo4j:不能用相同的标签创建两个关系属性

Question

@NodeEntity
public class Person {

    @GraphId Long id;
    public String name;

    public Person() {}
    public Person(String name) { this.name = name; }

    @RelatedTo(type="MEMBER_OF", direction=Direction.OUTGOING)
    Dojo dojo;

    @RelatedTo(type="MEMBER_OF", direction=Direction.OUTGOING)
    MailingList mailingList;

    public void setDojo(Dojo dojo) {
        this.dojo = dojo;
    }
    public void setMailingList(MailingList mailingList) {
        this.mailingList = mailingList;
    }

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

java：

@NodeEntity
public class Dojo {

    @GraphId Long id;
    public String name;

    public Dojo() { }
    public Dojo(String name) { this.name = name; }

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

MailingList.java：

@NodeEntity
public class MailingList {

    @GraphId Long id;
    public String name;

    public MailingList() { }
    public MailingList(String name) { this.name = name; }

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

}

application.java：

@Configuration
@EnableNeo4jRepositories(basePackages = "hello")
public class Application extends Neo4jConfiguration implements CommandLineRunner {

    public Application() {
        setBasePackage("hello");
    }

    @Bean
    GraphDatabaseService graphDatabaseService() {
        return new GraphDatabaseFactory().newEmbeddedDatabase("accessingdataneo4j.db");
    }

    @Autowired
    PersonRepository personRepository;

    @Autowired
    GraphDatabase graphDatabase;

    public void run(String... args) throws Exception {
        Transaction tx = graphDatabase.beginTx();
        try {
            Person linus = new Person("Linus");
            linus.setDojo(new Dojo("Coding Dojo"));
            linus.setMailingList(new MailingList("Kernel Mailing List"));

            personRepository.save(linus);

            tx.success();
        } finally {
            tx.close();
        }
    }

    public static void main(String[] args) throws Exception {
        FileUtils.deleteRecursively(new File("accessingdataneo4j.db"));

        SpringApplication.run(Application.class, args);
    }
}

@NodeEntity
public class Person {

    @GraphId Long id;
    public String name;

    public Person() {}
    public Person(String name) { this.name = name; }

    @RelatedTo(type="MEMBER_OF_DOJO", direction=Direction.OUTGOING)
    Dojo dojo;

    @RelatedTo(type="MEMBER_OF_LIST", direction=Direction.OUTGOING)
    MailingList mailingList;

    public void setDojo(Dojo dojo) {
        this.dojo = dojo;
    }
    public void setMailingList(MailingList mailingList) {
        this.mailingList = mailingList;
    }

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

从这个例子中我的理解是，spring-data-neo4j将不允许一个类拥有两个具有相同标签的属性。在某些情况下，不同的关系需要有相同的标签--例如，为了符合建模标准。是否可以在spring-data-neo4j中设置多个同名关系？如果是，怎么做？

Answer 1

我已经找到了这个问题的答案。我要查找的是文档中描述的“EnforceTargetType”属性。

我创建了一个使用此修复的存储库分支。它可以在https://github.com/spencerhrob/gs-accessing-data-neo4j/tree/same-name-enforce-target找到。

person.java：

@NodeEntity
public class Person {

    @GraphId Long id;
    public String name;

    public Person() {}
    public Person(String name) { this.name = name; }

    @RelatedTo(type="MEMBER_OF", direction=Direction.OUTGOING, enforceTargetType=true)
    Dojo dojo;

    @RelatedTo(type="MEMBER_OF", direction=Direction.OUTGOING, enforceTargetType=true)
    MailingList mailingList;

    public void setDojo(Dojo dojo) {
        this.dojo = dojo;
    }
    public void setMailingList(MailingList mailingList) {
        this.mailingList = mailingList;
    }

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