在RESTful web服务中接收带有@JoinColumn的Spring实体

Question

我有这些桌子：

CREATE TABLE ref.doc (
    id       serial PRIMARY KEY,
    iddoc    integer NOT NULL UNIQUE,
    docname  varchar(254) NOT NULL
);

CREATE TABLE person (
    id       serial PRIMARY KEY,
    name     varchar(40) DEFAULT NULL, 
    doctype  integer DEFAULT NULL REFERENCES ref.doc(iddoc)
);

我需要使用Spring构建一个RESTful Web服务，它接收JSON并在验证后将它们保存到数据库中。例如，在ref.doc中有一条带有iddoc=2的记录。因此人的JSON如下所示：

{
    "name": "John",
    "doctype": 2
}

我想这样做：

@RestController
public class PersonController {

    @Autowired
    PersonRepository personRepository;

    @Transactional
    @RequestMapping(value = "/add", method = RequestMethod.POST)
    @ResponseBody
    public Person add(@RequestBody Person person) {
        // some logic
        personRepository.saveAndFlush(person);
        return person;
    }
}

我拥有以下实体：

@Entity
@Table(schema = "ref")
public class Doc {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @JsonIgnore
    private long id;

    private Integer iddoc;
    private String docname;

    ...
}

@Entity
public class Person {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @JsonIgnore
    private long id;

    private String name;

    @ManyToOne
    @JoinColumn(name = "doctype", referencedColumnName = "iddoc", nullable = false)
    private Doc doc;

    ...
}

在这种情况下，person中的doc总是为null，这很容易理解。但是如何实现我需要的行为呢？

Answer 1

        @RestController
        public class PersonController {

            @Autowired
            PersonRepository personRepository;

            @Autowired
            DocRepository docRepository;

            @Transactional
            @RequestMapping("/add")
            @ResponseBody
            public void add(@RequestBody Person person) {
                Doc doc=docRepository.findByIddoc(person.getDoc().getIddoc());
                if(!(doc==null)){
                Person personAdd=new Person();
                personAdd.setName("name");
                personAdd.setDoc(doc);
                personRepository.saveAndFlush(person);
                }
            }
        }



    @Entity
    public class Person {

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        @JsonIgnore
        private long id;

        private String name;

        @ManyToOne(cascade=CascadeType.ALL)
        @JoinColumn(name = "doctype", referencedColumnName = "iddoc", nullable = false)
        private Doc doc;






@Entity
@Table(schema = "demo")
public class Doc {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @JsonIgnore
    private long id;

    private Integer iddoc;
    private String docname;

Answer 2

看到这个链接了吗？

http://www.javaworld.com/article/2077819/java-se/understanding-jpa-part-2-relationships-the-jpa-way.html

特别是查看订单表和客户表之间的关系。

据我所知，您需要一个人拥有多个文档。所以试着改变定义

private Doc doc;

到

@OneToMany(mappedBy="person", fetch=FetchType.EAGER)
   private List<Doc> docs;

并在Doc类中尝试添加以下内容：

 @ManyToOne(optional=false)
 @JoinColumn(name="doctype",referencedColumnName="iddoc")
   private Person person;

这应该是实现您需要的行为的正确方法，而不是100%确定。这是另一个解释如何实现您需要的解决方案的链接：

https://en.wikibooks.org/wiki/Java_Persistence/OneToMany