Spring Boot的Jpa ManytoMany问题 [英] Jpa ManytoMany issue with Spring Boot

问题描述

我有一个postgres数据库，我试图用Spring Boot做一个简单的REST服务。

个人实体：

  @Entity 
 @Table（name =person，schema =persons）
 public class Person实现Serializable {
 @Id 
 @GeneratedValue（strategy = GenerationType.IDENTITY ）
私人整数ID; 
 
 @Column（nullable = false）
私有字符串名称; 
 
 @Column（nullable = false）
 private String email; 
 
 @Column 
私人整数年龄; 
 
 @ManyToOne 
 @JoinColumn（name =country_id，referencedColumnName =id）
 private国家countryOfBirth; 
 
 @ManyToMany 
 @JoinTable（
 name =persons_countries_residence，
 joinColumns = @ JoinColumn（name =person_id，referencedColumnName =id），
 inverseJoinColumns = @ JoinColumn（name =country_id，referencedColumnName =id））
 private List< Country> countriesOfResidence; 
 
 // getters和setters和String方法重载
} 
  

国家实体：

  @Entity 
 @Table（name =country，schema =persons） 
 public class Country实现Serializable {
 @Id 
 @GeneratedValue（strategy = GenerationType.IDENTITY）
 private Integer id; 
 
 @Column（name =country_name）
私人字符串名称; 
 
 @Column（name =country_code）
私人字符串代码; 
 
 // getters和setters和String方法重载
} 
  

< Postgres架构如下：

Person Table：

  CREATE TABLE persons.person 
（
 id序列NOT NULL，
名称字符变化（50）NOT NULL，
电子邮件字符变化（40）NOT NULL，
年龄整数，
 country_id序列NOT NULL，
 CONSTRAINT ID PRIMARY KEY（id），
 CONSTRAINT country_id FOREIGN KEY（id）
 REFERENCES persons.country（id）MATCH SIMPLE 
 ON UPDATE NO ACTION ON DELETE NO ACTION 
）
  

国家/地区表：

  CREATE TABLE persons.country 
（
 id序列NOT NULL，
 country_name character varying（45） NOT NULL，
 country_code character varying（10）NOT NULL，
 CONSTRAINT country_id PRIMARY KEY（id）
）
  

加入表：

  CREATE TABLE persons.persons_ countries_residence 
（
 person_id integer NOT NULL，
 country_id integer NOT NULL，
 CONSTRAINT person_country_id PRIMARY KEY（person_id，country_id），
 CONSTRAINT persons_countries_residence_country_id_fkey FOREIGN KEY（country_id）
 REFERENCES persons.country（id）MATCH SIMPLE 
 ON UPDATE CASCADE ON DELETE NO ACTION，
 CONSTRAINT persons_countries_residence_person_id_fkey FOREIGN KEY（person_id）
 REFERENCES persons.person（id）MATCH SIMPLE 
 ON UPDATE CASCADE ON DELETE CASCADE 
）
  

当我进行HTTP方法调用时，

服务代码：

  @RequestMapping（method = RequestMethod.GET，产生= {MediaType.APPLICATION_JSON_VALUE，MediaType.APPLICATION_XML_VALUE}）
 public List< Person> getAllPersons（）{
 retutn jpaPersonRepository.findAll（）; 
} 
  

任何帮助表示赞赏。

  @ManyToMany 
 @JoinTable解决方案

（
name =persons_countries_residence，schema =persons，
joinColumns = @ JoinColumn（name =person_id，referencedColumnName =id），
inverseJoinColumns = @ JoinColumn（name = country_id，referencedColumnName =id））
私人列表< Country> countriesOfResidence;


架构必须在 @JoinTable 注释。

I have a postgres database and I am trying to make a simple REST service with Spring Boot. I have a problem with jpa ManytoMany relationship.

Person Entity:

@Entity
@Table(name = "person", schema = "persons")
public class Person implements Serializable {
@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
private Integer id;

@Column(nullable = false)
private String name;

@Column(nullable = false)
private String email;

@Column
private Integer age;

@ManyToOne
@JoinColumn(name = "country_id", referencedColumnName = "id")
private Country countryOfBirth;

@ManyToMany
@JoinTable(
        name="persons_countries_residence",
        joinColumns=@JoinColumn(name="person_id", referencedColumnName="id"),
        inverseJoinColumns=@JoinColumn(name="country_id", referencedColumnName="id"))
private List<Country> countriesOfResidence;

// getters and setters and to String method overriden
}

Country Entity:

@Entity
@Table(name = "country", schema = "persons")
public class Country implements Serializable {
@Id
@GeneratedValue(strategy= GenerationType.IDENTITY)
private Integer id;

@Column(name = "country_name")
private String name;

@Column(name = "country_code")
private String code;

 // getters and setters and to String method overriden
}

The postgres schema is the following:

Person Table:

CREATE TABLE persons.person
(
  id serial NOT NULL,
  name character varying(50) NOT NULL,
  email character varying(40) NOT NULL,
  age integer,
  country_id serial NOT NULL,
  CONSTRAINT id PRIMARY KEY (id),
  CONSTRAINT country_id FOREIGN KEY (id)
  REFERENCES persons.country (id) MATCH SIMPLE
  ON UPDATE NO ACTION ON DELETE NO ACTION
 )

Country table:

CREATE TABLE persons.country
(
  id serial NOT NULL,
  country_name character varying(45) NOT NULL,
  country_code character varying(10) NOT NULL,
  CONSTRAINT country_id PRIMARY KEY (id)
)

Join table:

CREATE TABLE persons.persons_countries_residence
(
  person_id integer NOT NULL,
  country_id integer NOT NULL,
  CONSTRAINT person_country_id PRIMARY KEY (person_id, country_id),
  CONSTRAINT persons_countries_residence_country_id_fkey FOREIGN KEY (country_id)
  REFERENCES persons.country (id) MATCH SIMPLE
  ON UPDATE CASCADE ON DELETE NO ACTION,
  CONSTRAINT persons_countries_residence_person_id_fkey FOREIGN KEY (person_id)
  REFERENCES persons.person (id) MATCH SIMPLE
  ON UPDATE CASCADE ON DELETE CASCADE
 )

When i make an HTTP method call, I don't get the Countries of residence.

Service code:

 @RequestMapping(method = RequestMethod.GET, produces =   {MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE})
 public List<Person> getAllPersons() {
     retutn jpaPersonRepository.findAll();
 }

Any help appreciated.

解决方案

The solution is this:

  @ManyToMany
  @JoinTable(
        name="persons_countries_residence", schema = "persons",
        joinColumns=@JoinColumn(name="person_id", referencedColumnName="id"),
        inverseJoinColumns=@JoinColumn(name="country_id", referencedColumnName="id"))
private List<Country> countriesOfResidence;

The schema had to be specified at the @JoinTable annotation as well.

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