Question

这就是我想要做的事情，它无法正常工作。

@DBRef( db = "employee")
    private Map<Role, List<Employee>> rolesByGroup;

Answer 1

你应该这样做：

public class EmployeeList {
    @DBRef public List<Employee> employees = new ArrayList<>();
}

private Map<Role, EmployeeList> rolesByGroup;

Answer 2

我不知道这是不是真的，但是目前我使用Spring Converter来解决这个问题。如果您的对象不太复杂，则可以执行相同的操作或进行改进，使它们更通用：

@WritingConverter
public class ChildWriteConverter implements Converter<Child, Document> {

@Override
public Document convert(Child source) {
    //TODO: Think about generic solution
    Document document = new Document();
    document.put("_id", source.getId());
    Map<String, List<Child>> children = source.getChildren();
    Document subdocument = new Document();
    if(children != null) {
        children.forEach((key, childList) -> {
            List<DBRef> dbList = new ArrayList<>(childList.size());
            childList.forEach(child -> {
                DBRef dbref = new DBRef("Child", child.getId());
                dbList.add(dbref);
            });
            subdocument.put(key, dbList);
        });
        document.put("children", subdocument);
    }
    return document;
}
}

还通过添加自定义转换来更新mongo的配置：

@Configuration
@EnableConfigurationProperties(MongoProperties.class)
@EnableMongoRepositories(basePackages = "com.my.repository")
public class MongoConfig extends AbstractMongoConfiguration {

private MongoProperties properties;

public MongoConfig(MongoProperties properties) {
    this.properties = properties;
}

@Override
public MongoClient mongoClient() {
    return new MongoClient(properties.getHost());
}

@Override
protected String getDatabaseName() {
    return properties.getDatabase();
}

@Bean
@Override
public CustomConversions customConversions() {
    List<Converter<?, ?>> converterList = new ArrayList<>();
    converterList.add(new ChildWriteConverter());
    return new MongoCustomConversions(converterList);
}
}

您还可以找到与此票有关的票证：https://jira.spring.io/browse/DATAMONGO-2132

如何使用带有列表作为值的映射的@DbRef？

2 个答案: