简单双向@OneToOne存储null

1-使用带有Java版本8的Spring工具套件在Eclipse中创建Spring Boot应用程序 2-添加依赖MySqlDriver和Spring Web 3-将pom中的依赖项添加到spring-boot-starter-data-jpa 4-在主包(com.onetoone)下为模型，控制器和存储库创建包 5-在模型包中创建类Phone y PhoneDetails，如文档中所述包com.onetoone.models; @Entity(name = "Phone")public class Phone { @Id @GeneratedValue private Long id; @Column(name = "`number`") private String number; @OneToOne( mappedBy = "phone", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY ) private PhoneDetails details; //Getters and setters are omitted for brevity public void addDetails(PhoneDetails details) { details.setPhone( this ); this.details = details; } public void removeDetails() { if ( details != null ) { details.setPhone( null ); this.details = null; } }}@Entity(name = "PhoneDetails")public class PhoneDetails { @Id @GeneratedValue private Long id; private String provider; private String technology; @OneToOne(fetch = FetchType.LAZY) @JoinColumn(name = "phone_id") private Phone phone; //Getters and setters are omitted for brevity}在文档中，他们将这些类创建为静态类，但是我必须将其删除，因为Eclipse表示:"Phone类的非法修饰符；仅公开，抽象和最终许可".我从javax.persistence导入了所有注释(@ Entity，@ Id ...). 6-在其程序包中创建接口PhoneController package com.onetoone.repository;import org.springframework.data.jpa.repository.JpaRepository;import com.onetoone.models.Phone;public interface PhoneRepository extends JpaRepository<Phone, Long> {} 7-创建PhoneController package com.onetoone.controllers;import java.util.Optional;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.ResponseEntity;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import com.onetoone.models.Phone;import com.onetoone.repository.PhoneRepository;@RestController@RequestMapping("/phone")public class PhoneController { @Autowired PhoneRepository phoneRepository; @PostMapping("/save") public ResponseEntity<Boolean> savePhone(@RequestBody Phone phone) { phoneRepository.save(phone); return ResponseEntity.ok(true); } @PostMapping("/get") public ResponseEntity<Optional<Phone>> getPhone(@RequestBody int i) { Long id = Long.valueOf(i); Optional<Phone> phone = phoneRepository.findById(id); return ResponseEntity.ok(phone); }} 8-在文件src/main/resources下设置application.properties spring.datasource.url= jdbc:mysql://localhost:3306/test?serverTimezone=UTCspring.datasource.username= rootspring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQL5Dialectspring.jpa.hibernate.ddl-auto= update我必须将?serverTimezone = UTC添加到数据库URL中，以免发生错误. 9-在我的本地数据库中创建一个名为test的模式 10-使用Spring Boot Dashboard启动应用程序，并创建表"phone"和"phone_details"(另一个称为"hibernate_sequence"的表) 11-我使用邮递员将剩下的内容发送到该网址http://localhost:8080/phone/保存该主体{ "number": "123-456-7890", "details": { "provider": "T-Mobile", "technology": "GSM" }} 12-这是问题所在.它会在电话表中创建一个条目(ID，号码) '1', '123-456-7890'和phone_details表中的其他内容(id，提供商，技术，phone_id)'2', 'T-Mobile', 'GSM', NULL 13-当然，如果我在网址1:http://localhost:8080/phone/get上贴上主体1，我会收信{ "id": 1, "number": "123-456-7890", "details": null}我希望任何人都可以帮助我，因为我尝试将代码减少到遵循文档的最低要求，但仍然存在问题:-( @JavaMan提供的解决方案足以满足示例要求，但不适用于复杂对象.我希望有人能帮助我！解决方案在PhoneController中，您必须添加以下行phone.getDetails().setPhone(phone);否则，Details对象将没有对电话的引用.像这样@PostMapping("/save")public ResponseEntity<Boolean> savePhone(@RequestBody Phone phone) { phone.getDetails().setPhone(phone); phoneRepository.save(phone); return ResponseEntity.ok(true);}此外，要使代码运行，请在PhoneDetails类的Phone字段中添加@JsonIgnore批注.I try to follow the @OneToOne bidrectional example from documetation but I always have a null reference in the PhoneDetails phone_id colum, and obtein a Phone with null details when do a get.I follow the documentation creating Phone and PhoneDetails Classes as is say.But because the documentation don't specify how to test and I need to develop an Spring Boot app, I create one to test and maybe, in any step of this I have the error.Here are my steps, and the code I update to github hoping someone can review it1 - Create a Spring Boot App in Eclipse with Spring tool suite with Java Version 82 - Add dependencies MySqlDriver and Spring Web3 - Add dependency in the pom to spring-boot-starter-data-jpa4 - Create packages under the main package (com.onetoone) for models, controllers and repository5 - Create in the model package the classes Phone y PhoneDetails as say in documentationpackage com.onetoone.models;@Entity(name = "Phone")public class Phone { @Id @GeneratedValue private Long id; @Column(name = "`number`") private String number; @OneToOne( mappedBy = "phone", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY ) private PhoneDetails details; //Getters and setters are omitted for brevity public void addDetails(PhoneDetails details) { details.setPhone( this ); this.details = details; } public void removeDetails() { if ( details != null ) { details.setPhone( null ); this.details = null; } }}@Entity(name = "PhoneDetails")public class PhoneDetails { @Id @GeneratedValue private Long id; private String provider; private String technology; @OneToOne(fetch = FetchType.LAZY) @JoinColumn(name = "phone_id") private Phone phone; //Getters and setters are omitted for brevity}In documentation they create this classes as static, but I have to remove it because Eclipse says: "Illegal modifier for the class Phone; only public, abstract & final are permitted".I import all the anotations (@Entity, @Id...) from javax.persistence.6 - Create interface PhoneController in his packagepackage com.onetoone.repository;import org.springframework.data.jpa.repository.JpaRepository;import com.onetoone.models.Phone;public interface PhoneRepository extends JpaRepository<Phone, Long> {}7 - Create PhoneControllerpackage com.onetoone.controllers;import java.util.Optional;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.ResponseEntity;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import com.onetoone.models.Phone;import com.onetoone.repository.PhoneRepository;@RestController@RequestMapping("/phone")public class PhoneController { @Autowired PhoneRepository phoneRepository; @PostMapping("/save") public ResponseEntity<Boolean> savePhone(@RequestBody Phone phone) { phoneRepository.save(phone); return ResponseEntity.ok(true); } @PostMapping("/get") public ResponseEntity<Optional<Phone>> getPhone(@RequestBody int i) { Long id = Long.valueOf(i); Optional<Phone> phone = phoneRepository.findById(id); return ResponseEntity.ok(phone); }}8 - Set the application.properties in his file under src/main/resourcesspring.datasource.url= jdbc:mysql://localhost:3306/test?serverTimezone=UTCspring.datasource.username= rootspring.jpa.properties.hibernate.dialect= org.hibernate.dialect.MySQL5Dialectspring.jpa.hibernate.ddl-auto= updateI have to add the ?serverTimezone=UTC to the database url to avoid an error.9 - Create an schema in my local database called test10 - Start the app with Spring Boot Dashboard, and it create the tables 'phone' and 'phone_details' (also another one called 'hibernate_sequence')11- I use postman to send a rest to this url http://localhost:8080/phone/save whit this body{ "number": "123-456-7890", "details": { "provider": "T-Mobile", "technology": "GSM" }}12 - And here is the problem. It create an entry in the phone table (id, number)'1', '123-456-7890'and other in the phone_details table (id, provider, technology, phone_id)'2', 'T-Mobile', 'GSM', NULL13 - Of course, if I do a post to url http://localhost:8080/phone/get with body 1 I recibe{ "id": 1, "number": "123-456-7890", "details": null}I hope anybody can help me because I try to reduce the code to the minimun to follow the documentation and still I have the issue :-(The solution gives by @JavaMan is enought for the example, but not for a complex object. I hope someoneelse can help me!!! 解决方案 In your PhoneController, you have to add the linephone.getDetails().setPhone(phone); otherwise the details object will not have a reference to the phone.So like this@PostMapping("/save")public ResponseEntity<Boolean> savePhone(@RequestBody Phone phone) { phone.getDetails().setPhone(phone); phoneRepository.save(phone); return ResponseEntity.ok(true);}Also, to get the code running add the @JsonIgnore annotation to your Phone field in your PhoneDetails class. 这篇关于简单双向@OneToOne存储null的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！