java - @Id 注释是什么？

Question

我有一个类有这个注释，@Id，它有什么用？

package oknok.validacao.resources;

import org.jongo.marshall.jackson.oid.Id;

public class Validacao {

    @Id
    String id;
    String email;
    String instancia;
    String dataCriacao;
    String dataAtualizacao;

}

Answer 1

此注释将字段标记为 Mongo 文档标识符。

unique identifier available on every Mongo document. If it isn't setted, it is generated. To handle it with Jongo, one attribute has to be named _id or annotated with @Id (alias for @JsonProperty("_id"))

引自jongo spec

您可以阅读更多有关 Mongo 文档 ID here 的信息.