Java Spring引导Rest API空Post属性

我是SpringBoot新手，我想编写我的第一个RESTAPI

首先，我的模型：

package entity;

import base.BaseEntityAudit;
import lombok.Data;

import javax.persistence.*;
import java.util.List;

@Data
@Entity
public class Country extends BaseEntityAudit {

    @Column(nullable = false)
    private String countryName;

    @Column(nullable = false)
    private String alpha2Code;
@OneToMany(mappedBy = "country", cascade = CascadeType.ALL, fetch = FetchType.EAGER)
private List<League> leagues;

public Country(String countryName, String alpha2Code) {
    this.countryName = countryName;
    this.alpha2Code = alpha2Code;
}

public Country() {
}


}

这一个有一个单一的协会。所以每个联赛都有一个国家

我认为重要的是联盟实体的控制者。有一个Post端点。如果我创建了一个新的联盟，我想发送一个国家Id来将联盟与一个国家关联起来，但我的问题是，“国家”属性始终为空，尽管我在post请求中发送了它

    import org.springframework.web.bind.annotation.*;
import repository.CountryRepository;
import repository.LeagueRepository;
import response.StandardResponse;

import java.util.List;

@RestController
@RequestMapping(path = "/api/v1")
public class LeagueController {
    Logger logger = LoggerFactory.getLogger(LeagueController.class);

    private final LeagueRepository dataRepo;
    private final CountryRepository countryRepository;

    public LeagueController(@Autowired LeagueRepository datarepo, CountryRepository countryRepository) {
        this.dataRepo = datarepo;
        this.countryRepository = countryRepository;
    }

    @GetMapping(path = "/league", produces = MediaType.APPLICATION_JSON_VALUE)
    public StandardResponse getAllLeagues() {
        List<League> leagues = this.dataRepo.findAll();

        return new StandardResponse(HttpStatus.OK, leagues);
    }

    @PostMapping(path = "/league/add", consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
    public StandardResponse createLeague(League l) {
        System.out.println(l);
        League league = this.dataRepo.save(l);

        return new StandardResponse(HttpStatus.OK, league);
    }
}

这是我的基本审计。我使用它为每个实体自动设置updatedAt和createdAt字段：

    package base;

import org.springframework.data.jpa.domain.support.AuditingEntityListener;

import javax.persistence.*;
import java.util.Date;

@EntityListeners(AuditingEntityListener.class)
@MappedSuperclass
public abstract class BaseEntityAudit extends BaseEntity {
    @Column(name = "createdAt")
    @Temporal(TemporalType.TIMESTAMP)
private Date createdAt = new Date();

@Column(name = "updatedAt")
@Temporal(TemporalType.TIMESTAMP)
private Date updatedAt = new Date();

public Date getCreatedAt() {
    return createdAt;
}

public void setCreatedAt(Date createdAt) {
    this.createdAt = createdAt;
}

public Date getUpdatedAt() {
    return updatedAt;
}

public void setUpdatedAt(Date updatedAt) {
    this.updatedAt = updatedAt;
}

@PrePersist
public void setCreationDate() {
    this.createdAt = new Date();
}

/**
 * Sets updatedAt before update
 */
@PreUpdate
public void setChangeDate() {
    this.updatedAt = new Date();
}
}

---

在RESTAPI中，如果要发布对象，需要使用

@RequestBody

注释。所以修改你的控制器

 @PostMapping(path = "/league/add" , consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
    public StandardResponse createLeague(League l) {
        System.out.println(l);
        League league = this.dataRepo.save(l);

        return new StandardResponse(HttpStatus.OK, league);
    }

到

现在在联赛课上评论这一部分

  @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "country_id", referencedColumnName = "id")
    private Country country;

---

现在，在邮递员发布的数据中，如下图所示，我认为您的装饰标签不正确。我的RESTful API请求如下所示：

@RequestMapping(value = "/something", method = RequestMethod.POST)
    private @ResponseBody Antenna someMethod(@RequestBody Object o) {
        o.doSomthing();
    return o;
    }

看

---

是国家为空，还是整个联盟（l）对象为空？国家为空null@b0ss你查过我的答案了吗？对不起，我没有时间。现在我收到了这样一条消息：“JSON解析错误：无法构造

实体.Country

的实例（尽管至少存在一个创建者）：没有int/int参数构造函数/工厂方法从数值（1）反序列化；嵌套异常为com.fasterxml.jackson.databind.exc.MismatchedInputException:无法构造

实体.Country

的实例（尽管至少存在一个创建者）：在[Source:（PushbackInputStream）；第4行，第13列]没有int/int参数构造函数/工厂方法从数值（1）反序列化（通过引用链：entity.League[\“country\”]），这给了我：“Content type'application/x-www-form-urlencoded；charset=UTF-8'不受支持”@b0ss您可以检查数据库是否保存了数据吗？@b0ss您可以尝试从

@PostMapping（path=“/League/add”）中删除所有参数吗

。请尝试在我编写时编写控制器。它不会保存，如果我删除了我获取的参数：“无法执行语句；SQL[n/a]；约束[null]；嵌套异常为org.hibernate.exception.ConstraintViolationException:无法执行语句”@b0ss您收到错误，因为您的某些实体值在发布期间可能为null。因此，请尝试删除“@Column（nullable=false）`此类型验证。或者确保所有具有验证的实体值均不为null。错误：“Content type”application/x-www-form-urlencoded；charset=UTF-8“不支持”

 @PostMapping(path = "/league/add")
    public StandardResponse createLeague(@RequestBody League l) {
        System.out.println(l);
        League league = this.dataRepo.save(l);

        return new StandardResponse(HttpStatus.OK, league);
    }

  @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "country_id", referencedColumnName = "id")
    private Country country;

@RequestMapping(value = "/something", method = RequestMethod.POST)
    private @ResponseBody Antenna someMethod(@RequestBody Object o) {
        o.doSomthing();
    return o;
    }