春季数据中的本机查询联接答案

【问题标题】：native query join in spring data春季数据中的本机查询联接
【发布时间】：2016-12-04 16:29:29
【问题描述】：

我有课：

@Entity
public class User {
    @Id
    Long id;
    String name;

    @ManyToMany
    List<Mission> missions;
}

@Entity
public class Mission {
    @Id
    Long id;
    String name;

    @ManyToMany
    List<User> users;
}

public interface MissionRepository extends CrudRepository<Mission, Long> {
    @Query(nativeQuery = true, "select * from mission join user on id = user_id where name = ?1")
    public List<Mission> findByname(String name);
}

我想知道是否可以在 Spring Data JPA 中使用本机查询连接，以及查询结果是否正确映射到上述示例中的实体。

谁能给我一个完整的例子来使用它。在我的情况下，我必须使用本机查询，但我不确定它是否有效。

【问题讨论】：

标签： java spring spring-data spring-data-jpa

【解决方案1】：

您可以通过使用命名的本机查询和结果集映射来做到这一点这是一个完整的例子

任务实体

package com.ntg.crm.internal.entites;

import java.math.BigInteger;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.EntityResult;
import javax.persistence.FetchType;
import javax.persistence.FieldResult;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.NamedNativeQuery;
import javax.persistence.SqlResultSetMapping;

@SqlResultSetMapping(name = "Mission.findAllMissionsMapping", entities = @EntityResult(entityClass = Mission.class, fields = {
        @FieldResult(name = "name", column = "mname"), @FieldResult(name = "id", column = "mid")
}))
@NamedNativeQuery(name = "Mission.findAllMissions", query = "select m.id as mid,m.name as mname , info.id uid ,info.name uname from Mission m join user_info_missions um on m.id "
        + "= um.missions_id join user_Info info on info.id = um.user_id where info.name =:userName", resultSetMapping = "Mission.findAllMissionsMapping")

@Entity
public class Mission {

    public Mission() {

    }

    public Mission(BigInteger id, String name) {
        super();
        this.id = id;
        this.name = name;
    }

    public Mission(BigInteger id, String name, List<User> users) {
        super();
        this.id = id;
        this.name = name;
        this.users = users;
    }

    @Id
    BigInteger id;
    String name;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(name = "user_info_missions", joinColumns = @JoinColumn(name = "missions_id"), inverseJoinColumns = @JoinColumn(name = "user_id"))
    List<User> users;

    public BigInteger getId() {
        return id;
    }

    public void setId(BigInteger id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<User> getUsers() {
        return users;
    }

    public void setUsers(List<User> users) {
        this.users = users;
    }

}

用户实体

package com.ntg.crm.internal.entites;

import java.util.List;

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

import com.fasterxml.jackson.annotation.JsonIgnore;

@Entity
@Table(name = "userInfo")
public class User {

    @Id
    long id;
    String name;

    @ManyToMany(targetEntity = Mission.class)
    @JoinTable(name = "user_info_missions", joinColumns = @JoinColumn(name = "user_id"), inverseJoinColumns = @JoinColumn(name = "missions_id"))
    @JsonIgnore
    List<Mission> missions;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<Mission> getMissions() {
        return missions;
    }

    public void setMissions(List<Mission> missions) {
        this.missions = missions;
    }

}

存储库功能

public List<Mission> findAllMissions(@Param("userName") String userName);

控制器功能

@Autowired
    TestRepository testRepo;

    @RequestMapping(value = "", method = RequestMethod.GET, produces = "application/json", consumes = "application/json")
    @ResponseBody
    List<Mission> getall() {
        List<Mission> missions = testRepo.findAllMissions("Test");
        return missions;
    }

这就是结果

[
  {
    "id": 1,
    "name": "Mission 1",
    "users": [
      {
        "id": 1,
        "name": "Test"
      }
    ]
  },
  {
    "id": 2,
    "name": "Mission 2",
    "users": [
      {
        "id": 1,
        "name": "Test"
      }
    ]
  }
]

【讨论】：

感谢您的回答，但我想知道查询结果是否正确映射到实体任务。换句话说，我可以在这个请求之后获得用户列表吗？
很好的例子！顺便说一句，您可以使用 Lombok 注释（如 @Data）来减少实体的 getter/setter 和其他样板。

【解决方案2】：

@middy62 你可以使用下面的查询。我已经使用您的示例来编写查询。希望它可以帮助某人。

@Query(nativeQuery = true, value = "select m from Mission join m.user u where name =:name") public List<Mission> findByname(@Param("name") String name);

请注意，当您在域实体模型上正确映射时，查询有效。

【讨论】：