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我正在使用 Spring Boot 测试 Neo4j，当我尝试使用 Rest API 插入元素时发现以下问题，我收到无法将 JSON 序列化为实体的错误。如果有人可以帮助我或解释如何更改我的代码或如何序列化该实体，我将非常感激。我的课程是......用户实体

@NodeEntity
public class User extends AbstractEntity{

    @Id
    @GeneratedValue
    private Long id;

    private String firstname, lastname;


    @NotNull @NotBlank @Email
    @Index(unique = true)
    private String email;

    @Index(unique = true)
    private String phone;

    @Relationship(type = "ADDRESS")
    private Set<Address> addresses = new HashSet<>();

    public User() {
    }
    //get & set & const....
    }

地址实体

@NodeEntity
public class Address extends AbstractEntity{
    /*Update the OMG [https://neo4j.com/developer/neo4j-ogm] and remove de id.
     Keep the id in AbstractEntity*/
    @Id
    @GeneratedValue
    private Long id;

    private String street, city;

    @Relationship(type = "COUNTRY")
    private Country country;

    public Address(String street, String city, Country country) {
        this.street = street;
        this.city = city;
        this.country = country;
    }

    public Address() {
    }
    //get & set & const...
    }

国家实体

@NodeEntity
public class Country extends AbstractEntity {
    /*Update the OMG [https://neo4j.com/developer/neo4j-ogm] and remove de id.
     Keep the id in AbstractEntity*/
    @Id
    @GeneratedValue
    private Long id;

    @Index(unique=true)
    private String code;

    private String name;

    public Country(String code, String name) {
        this.code = code;
        this.name = name;
    }

    public Country() {
    } 
  }

抽象实体

@EnableNeo4jAuditing
public abstract class AbstractEntity {

    public abstract Long getId();

    @Transient
    private SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy");

    private Date created = new Date();

    public Date getCreated() {
        return created;
    }

    public void setCreated(Date created) {
        this.created = created;
    }

    @Override
    public boolean equals(Object obj) {

        if (this == obj) {
            return true;
        }

        if (getId() == null || obj == null || !getClass().equals(obj.getClass())) {
            return false;
        }
        return getId().equals(((AbstractEntity) obj).getId());

    }

    @Override
    public int hashCode() {
        return getId() == null ? 0 : getId().hashCode();
    }
}

我的商店用户的简单存储库类

public interface UserRepository extends Neo4jRepository<User, Long> {

    User findByFirstname(String name);

    @Override
    void delete(User deleted);
}

我的服务类

@Service
public class UserService {
     private UserRepository userRepository;
    @Autowired
    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }
    public Iterable<User> contact() {
        return userRepository.findAll();
    }
    public User save(User user) {
            userRepository.save(user);
            return user;
    }
    public User show(Long id) {
        return userRepository.findById(id).get();
    }
    public User update(Long id, User user) {
        User c = userRepository.findById(id).get();
        if(user.getFirstname()!=null && !user.getFirstname().trim().isEmpty())
            c.setFirstname(user.getFirstname().trim());
        if(user.getLastname()!=null && !user.getLastname().trim().isEmpty())
            c.setLastname(user.getLastname().trim());
        if(user.getEmail()!=null && !user.getEmail().trim().isEmpty())
            c.setEmail(user.getEmail().trim());
        userRepository.save(c);
        return user;
    }
    public String delete(Long id) {
        User user = userRepository.findById(id).get();
        userRepository.delete(user);

        return "";
    }
}

我的控制器类

@RestController
public class UserController {
    @Autowired
    UserService userService;

    @RequestMapping(method = RequestMethod.GET, value = "/users")
    public Iterable<User> user() {
        return userService.contact();
    }

    @RequestMapping(method = RequestMethod.POST, value = "/users")
    public String save(@RequestBody User user) {
        try {
            userService.save(user);
        }catch (org.neo4j.driver.v1.exceptions.ClientException ex){
            System.err.println("******||||||||||||[{   The User exist with the same email   }]||||||||||||******");
        return "The User exist with the same email";
        }
        return user.toString();
    }
    @RequestMapping(method=RequestMethod.GET, value="/users/{id}")
    public User show(@PathVariable Long id) {
        try{
        return userService.show(id);}
        catch (java.util.NoSuchElementException ex){
            System.err.println("******||||||||||||[{   The User do not exist    }]||||||||||||******");
        }
        return null;
    }
    @RequestMapping(method=RequestMethod.PUT, value="/users/{id}")
    public User update(@PathVariable Long id, @RequestBody User user) {
        return userService.update(id, user);
    }
    @RequestMapping(method=RequestMethod.DELETE, value="/users/{id}")
    public String delete(@PathVariable Long id) {
        return userService.delete(id);
    }

}

这是我尝试建模的简单方案（Neo4j 是一个 NoSQL 数据库，没有大纲，但我尝试建模一个简单的应用程序） 在此处输入图像描述

当它尝试测试 api rest 的方法时，它对我有用，但 Country 实体未序列化为 json。

我已经将数据插入到数据库中，我使用测试方法声明了对象并使用方法保存它。当我使用 json 格式时会出现问题。当我运行 curl 命令测试 Rest API 时，它不返回国家/地区

$ curl -i -H "Accept: application/json" localhost:8088/users/1
HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Date: Thu, 27 Sep 2018 20:38:31 GMT

{"created":"2018-09-27T19:55:21.578+0000","id":1,"firstname":"Yuniel","lastname":"Acosta Pérez","email":"yuniel.acosta@someserver.com","phone":"+999999999999","addresses":[{"created":"2018-09-27T19:55:21.578+0000","id":0,"street":"Some Stree","city":"Some City","country":null}]}

如您所见，国家将其作为空值返回，如果它存在于数据库中。

当我尝试使用 API 插入一个元素时，它感叹一个错误，即我无法将国家对象序列化为 JSON。

$ curl -i -X POST -H "Content-Type: application/json" -d '{"firstname":"Yuniel","lastname":"Acosta Pérez","email":"yuniel.acosta@someserver.com","phone":"+999999999999","addresses":[{"street":"Some Stree","city":"Some City","country":[{"code":"OO","name":"ANYCOUNTRY"}]}]}' localhost:8088/users

下一个错误是抛出我的那个

{"timestamp":"2018-09-27T21:07:56.365+0000","status":400,"error":"Bad Request","message":"JSON 解析错误：无法反序列com.syskayzen.hypercube.domain.Address化 START_ARRAY 的实例令牌；嵌套异常是 com.fasterxml.jackson.databind.exc.MismatchedInputException：无法com.syskayzen.hypercube.domain.Address在 [Source: (PushbackInputStream); line: 1, column: 122] 处反序列化 START_ARRAY token\n 之外的实例（通过引用链：com. syskayzen.hypercube.domain.User[\"addresses\"])","path":"/users"}

如果您能告诉我如何解决如何序列化国家实体的问题，或者是否是由于其他原因导致错误。

我正在使用 Spring Boot 2.0.5 和 Spring Data Neo4j

4

1 回答 1

1

我相信 Country 在您的 curl 命令中返回 null 的原因是因为查询仅在数据库中深入 1 跳。因此，它正在拉用户，然后走 1 跳以拉地址节点，但随后它停止了。要让它沿路径拉更多的跃点，您需要指定深度。

您可以通过在 curl 命令中指定深度并为“int depth”添加参数来传递存储库调用来完成此操作。这将允许您拥有动态深度，以防您向要检索的应用程序添加更多跃点。

服务方法看起来像这样......

public User show(Long id, int depth) {
        return userRepository.findById(id, depth).get();
}

相关文档位于以下链接：https ://docs.spring.io/spring-data/neo4j/docs/5.1.0.RELEASE/reference/html/#reference:session:persisting-entities:save-depth

于 2018-10-05T16:32:48.047 回答