我正在尝试在两个实体之间实现一对多Map。在这里，名称有一个位置，而位置有多个名称。一旦我添加了名称，它就Map得很好，但它会更新位置表，除了id之外为空。
这里我使用的是Microsoft SQL服务器。应用程序属性

#for ms server
spring.datasource.url = jdbc:sqlserver://localhost\\sqlexpress;databaseName=nifs_database;encrypt=true;trustServerCertificate=true
spring.datasource.username = viranga
spring.datasource.password = ********

spring.jpa.hibernate.ddl-auto=update
spring.jpa.properties.hibernate.format_sql = true
spring.jpa.hibernate.dialect=org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.properties.hibernate.globally_quoted_identifiers=true
#spring.main.allow-circular-references=true
spring.jackson.serialization.fail-on-empty-beans=false

主标识

package com.nifs.backend.Admin.EmployeeDesignation;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.nifs.backend.Admin.Locations.Locations;
import jakarta.persistence.*;
import lombok.*;
import java.util.Date;

@Entity
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@Table(name = "designation_master")
public class DesignationMaster {

    @Id
    @Column(name = "id", nullable = false, length = 10)
    private String id;

    @Column(name = "designation_name", length = 255)
    private String designationName;

    @ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.MERGE})
    @JoinColumn(name = "location_id", referencedColumnName = "location_id", nullable = false)
    @JsonIgnoreProperties("designations")
    private Locations location;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="date_created")
    private Date dateCreated;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="date_updated")
    private Date dateUpdated;
}

位置管理器

package com.nifs.backend.Admin.Locations;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.nifs.backend.Admin.EmployeeDesignation.DesignationMaster;
import com.nifs.backend.Admin.OtherData.District;
import jakarta.persistence.*;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import java.util.Date;
import java.util.List;
import java.util.Set;

@Entity
@Setter
@Getter
@NoArgsConstructor
@AllArgsConstructor
@Table(name = "locations_master")
public class Locations {

    @Id
    @Column(name = "location_id", nullable = false, length = 10)
    private String locationId;

    @Column(name = "location_name", length = 100)
    private String locationName;

    @Column(name = "address", length = 255)
    private String address;

    @Column(name = "tel_no", length = 15)
    private String telNo;

    @Column(name = "fax_no", length = 15)
    private String faxNo;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="date_created")
    private Date dateCreated;

    @Temporal(TemporalType.TIMESTAMP)
    @Column(name="date_updated")
    private Date dateUpdated;

//    relationships

    @OneToMany(mappedBy = "location", cascade = {CascadeType.MERGE}, fetch = FetchType.LAZY)
    @JsonIgnoreProperties("location")
    private List<DesignationMaster> designations;

}

指定的服务等级

@Service
public class DesignationService {

    @Autowired
    private DesignationRepostory desRepo;

    @Autowired
    private LocationRepository locRepo;

//    get all designations
    public List<DesignationMaster> getAllDesignations() {
        return desRepo.findAll();
    }

    public Boolean createDesignation(DesignationMaster desData) {
        if(desRepo.returnDesignation(desData.getId()) == null){
            Date d = new Date();
            desData.setDateCreated(d);
            desRepo.save(desData);
            return true;
        }
        return false;
    }
}

名称的控制器类别

@RestController
@RequestMapping("admin/designation")
public class DesignationController {

    @Autowired
    private DesignationService desService;

//    get all designations
    @GetMapping
    private List<DesignationMaster> getAllDesignations(){
        return desService.getAllDesignations();
    }

    @GetMapping("/newid")
    private String returnNewId(){
        return desService.returnNewId();
    }
//    create designation
    @PostMapping
    private Boolean createDesignation(@RequestBody DesignationMaster desData){
        return desService.createDesignation(desData);
    }

我将数据传递到后端，如下所示

{
    "id": "DM1003",
    "designationName": "Driver",
    "location": {
          "locationId": "LM1001"
    }
}

它更新了数据库，但将location表中的其他值更改为null，并获得如下请求

{
        "id": "DM1001",
        "designationName": "Lecturer",
        "location": {
            "locationId": "LM1001",
            "locationName": null,
            "address": null,
            "telNo": null,
            "faxNo": null,
            "dateCreated": null,
            "dateUpdated": null,
            "hibernateLazyInitializer": {}
        },
        "dateCreated": "2022-12-21T13:56:32.429+00:00",
        "dateUpdated": null
    }

与数据库中相同-位置表x1c 0d1x

• 名称表
  

我尝试了很多方法，但没有一种对我有效。有没有人能让我的一天过得更好？