Spring数据jpa和具有某种关系的实体

Question

I'm writing a sample app using the HR schema on an Oracle db 18c.

I'm using Spring boot 2, Spring Data Jpa and Spring Rest. I'm working on Regions ' table (that contains two fields: region_id and region_name ) and countries table (that contains three fields: country_id , country_name and region_id ).

I can manage all CRUD operation on Regions' table if its entity doesn't contain the relationship @OneToMany with Country's entity when I add it the application return me a 415 error (non supported method) that have no sense! Here it is my code:

Region Entity:

package it.aesys.springhr.entities;

import javax.persistence.*;

import com.fasterxml.jackson.annotation.JsonBackReference;

import java.util.List;


/**
 * The persistent class for the REGIONS database table.
 * 
 */
@Entity
@Table(name="REGIONS")
@NamedQuery(name="Region.findAll", query="SELECT r FROM Region r")
public class Region  {

    @Id
    @GeneratedValue(generator="REGIONS_SEQ", strategy=GenerationType.SEQUENCE)
    @SequenceGenerator(name="REGIONS_SEQ", sequenceName="REGIONS_SEQ", allocationSize=0)
    @Column(name="REGION_ID", unique=true, nullable=false)
    private int regionId;

    @Column(name="REGION_NAME", nullable=false, length=50)
    private String regionName;

    //bi-directional many-to-one association to Country
    @OneToMany(mappedBy="region", cascade = CascadeType.ALL)
// this annotation help me to not retrieve all countries when I find all Regions but I tried also without it and anything change
    @JsonBackReference
    private List<Country> countries;
// constructor, getters and setters as usual
}

Country Entity:

package it.aesys.springhr.entities;


import javax.persistence.*;

import com.fasterxml.jackson.annotation.JsonBackReference;
import com.fasterxml.jackson.annotation.JsonManagedReference;

import java.util.List;


/**
 * The persistent class for the COUNTRIES database table.
 * 
 */
@Entity
@Table(name="COUNTRIES")
@NamedQuery(name="Country.findAll", query="SELECT c FROM Country c")
public class Country  {

    @Id
    @Column(name="COUNTRY_ID", unique=true, nullable=false, length=2)
    private String countryId;

    @Column(name="COUNTRY_NAME", nullable=false, length=40)
    private String countryName;

    //bi-directional many-to-one association to Region
    @ManyToOne
    @JoinColumn(name="REGION_ID")
    @JsonManagedReference
    private Region region;
// constructor, getters and setters as usual
}

The RegionRepository Interface is simply:

package it.aesys.springhr.dao;
import java.util.List;

import org.springframework.data.jpa.repository.JpaRepository;

import it.aesys.springhr.entities.Region;

public interface RegionRepository extends JpaRepository<Region, Integer> {
}

and the RegionService contains this method:

public void save(Region theRegion) {
    regionRepository.save(theRegion);
}

and finally the RegionRestController contains this method:

@PostMapping( value= "/regions", consumes = "application/json;charset=UTF-8", produces = "application/json;charset=UTF-8")
public Region addRegion(@RequestBody Region theRegion) {

    // also just in case they pass an id in JSON ... set id to 0
    // this is to force a save of new item ... instead of update

    theRegion.setRegionId(0);

    regionService.save(theRegion);

    return theRegion;
}

I'm using CURL to test this app and I tried to pass countries in different ways but no one works!

Can I resolve without using some external framework like Map Struct? Or, in this case I MUST create a new object that mapping what I receive with what I must persist?

[Edit]: I modify the last method with this code: @PostMapping( value= "/regions", consumes = "application/json;charset=UTF-8", produces = "application/json;charset=UTF-8") public Region addRegion(@RequestBody HashMap) { Region theRegion= new Region(); theRegion.setRegionId(0); theRegion.setRegionName(map.get("regionName"));

    regionService.save(theRegion);

    return theRegion;
}

and now it works but I'm not sure that this solution is secure because it seems so simply and so generic ...

Answer 1

As I edited, I modify the last method with this code:

@PostMapping( value= "/regions", consumes = "application/json;charset=UTF-8", produces = "application/json;charset=UTF-8")
public Region addRegion(@RequestBody HashMap<String, String>) {
    Region theRegion= new Region(); 
    theRegion.setRegionId(0);
    theRegion.setRegionName(map.get("regionName"));

    regionService.save(theRegion);

    return theRegion;
}

and now it works but I'm not sure that this solution is secure because it seems so simply and so generic so if you think that it is not sure please answer and tell me another better solution!

Answer 2

您可以在服务类和控制器类中使用@Component在主类中使用@Component @ComponentScan(basePackages = "<full package name>" 。问题可能会得到解决。