发行

大家好，请帮我解决这个问题。我已经开始构建restapi，在测试我创建的url时遇到了一个问题。示例：当我发送请求以获取一个对象的列表时，请求工作正常，但是json返回的数据语法很难看：我得到的是结果嵌套数组，而不是一个包含json对象的全局数组。请检查我的代码，我现在有两个实体，其中一个依赖于另一个，我用@onetomany建立了它们之间的关系，没有发生错误。提前谢谢。

解决方案

问题是：我的查询在默认情况下返回一个列表列表，因此我必须通过添加构造函数调用来修改查询。请检查以下链接：在hql查询中使用new关键字
此外，我还添加了@jsonignore注解来忽略实体中的一些属性，以防止它们显示出来。现在数据显示为我想要的格式：d谢谢你的帮助。在这里检查新结果

更新

您好，我最近意识到，使用@jsonignore注解来阻止在json响应中发送某些属性是不好的，自定义要发送哪些属性的最好方法是使用dtos类。再次感谢kj007
实体1

import java.util.List;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;

import lombok.Data;

 @Data
    @Table(name = "x_assureurs") // this is the table name in DB
    @Entity(name = "Assureurs") // This tells Hibernate to make a table out of this class
    public class Assureurs {

        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        @Column(name = "n_assureur")
        private String id;

        @Column(name = "nom_assureur")
        private String name;

        @OneToMany(mappedBy="assureur",fetch = FetchType.LAZY)
        private List<Contrats> contrats;

    }

实体2

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

import lombok.Data;

@Data
@Table(name = "contrats") // this is the table name in DB
@Entity(name = "Contrats") // This tells Hibernate to make a table out of this class
public class Contrats {

    @Id
    @Column(name = "id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @Column(name = "num_contrat")
    private String num;

    @Column(name = "nom_police")
    private String nomPolice;

    @ManyToOne
    @JoinColumn(name = "courtier")
    private Courtiers courtier;

    @ManyToOne
    @JoinColumn(name = "assureur")
    private Assureurs assureur;

}

存储库

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;

import tn.igase.gestdoc.models.entities.Assureurs;

// This will be AUTO IMPLEMENTED by Spring into a Bean called assureurRepository

@Repository
public interface AssureurRepository extends JpaRepository<Assureurs, String> {

    // CONSTANTS
    String FIND_ALL_BY_CONTRATS = "SELECT DISTINCT(contrat.assureur.id) as n_assureur, assureur.name \n"
            + " FROM Contrats contrat \n" + " JOIN Assureurs assureur ON contrat.assureur.id = assureur.id ";
    String BY_ONE_COURTIER = "WHERE contrat.courtier.id = :idCourtier";

    // QUERIES
    @Query(FIND_ALL_BY_CONTRATS)
    Iterable<Assureurs> findAllByContrats();

    @Query(FIND_ALL_BY_CONTRATS + BY_ONE_COURTIER)
    Iterable<Object> findAllByContratsAndCourtier(@Param("idCourtier") int idCourtier);

}

服务

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import tn.igase.gestdoc.daos.AssureurRepository;
import tn.igase.gestdoc.models.entities.Assureurs;

@Service
public class AssureurService {

   @Autowired
   AssureurRepository assureurRepository;   

   public Iterable<Assureurs> findAllByContrats() {
        return assureurRepository.findAllByContrats();
    }
}

控制器

import java.util.ArrayList;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import tn.igase.gestdoc.models.entities.Assureurs;
import tn.igase.gestdoc.service.AssureurService;
import tn.igase.gestdoc.service.ContratService;

/**
 * 
 * Assureur controller
 * 
 * @author fre
 */
@RestController
@RequestMapping(path = "/api/assureurs")
public class AssureurController extends MainController {

    @Autowired
    private AssureurService assureurService;
    /**
     * Revert all assureurs that all have contrats
     * 
     * @return list
     */
    @RequestMapping(path = "/all", produces=MediaType.APPLICATION_JSON_VALUE)
    public Iterable<Assureurs> getAll() {
        // This returns a JSON or XML with the users

        Iterable<Assureurs> assureurs = new ArrayList<>();
        assureurs = assureurService.findAllByContrats();
        return assureurs;
    }
}

结果检查此处返回的json数据